From 3982cef2558c4d98c0b7cb268643a7dafad59950 Mon Sep 17 00:00:00 2001
From: Gregory Albouy <gregoryalbouy75@gmail.com>
Date: Sat, 5 Nov 2022 13:09:56 +0100
Subject: [PATCH 01/10] feat(configio): implement Builder

---
 configio/builder.go        | 161 +++++++++++++++++++++++++++++++++++++
 configio/builder_test.go   | 148 ++++++++++++++++++++++++++++++++++
 configio/representation.go |   4 +
 3 files changed, 313 insertions(+)
 create mode 100644 configio/builder.go
 create mode 100644 configio/builder_test.go

diff --git a/configio/builder.go b/configio/builder.go
new file mode 100644
index 0000000..ad15021
--- /dev/null
+++ b/configio/builder.go
@@ -0,0 +1,161 @@
+package configio
+
+import (
+	"io"
+	"net/http"
+	"net/url"
+	"time"
+
+	"github.com/benchttp/sdk/benchttp"
+)
+
+type Builder struct {
+	// TODO: benchmark this vs []func(*benchttp.Runner)
+	modifier func(*benchttp.Runner)
+}
+
+func (b *Builder) WriteJSON(in []byte) error {
+	return b.decodeAndWrite(in, FormatJSON)
+}
+
+func (b *Builder) WriteYAML(in []byte) error {
+	return b.decodeAndWrite(in, FormatYAML)
+}
+
+func (b *Builder) decodeAndWrite(in []byte, format Format) error {
+	repr := Representation{}
+	if err := DecoderOf(format, in).Decode(&repr); err != nil {
+		return err
+	}
+	if err := repr.validate(); err != nil {
+		return err
+	}
+	b.pipe(func(dst *benchttp.Runner) {
+		_ = repr.Into(dst)
+	})
+	return nil
+}
+
+func (b *Builder) Runner() benchttp.Runner {
+	runner := benchttp.Runner{}
+	b.into(&runner)
+	return runner
+}
+
+func (b *Builder) Into(dst *benchttp.Runner) {
+	b.into(dst)
+}
+
+func (b *Builder) into(dst *benchttp.Runner) {
+	if b.modifier == nil {
+		return
+	}
+	b.modifier(dst)
+}
+
+// setters
+
+func (b *Builder) SetRequest(r *http.Request) {
+	b.pipe(func(runner *benchttp.Runner) {
+		runner.Request = r
+	})
+}
+
+func (b *Builder) SetRequestMethod(v string) {
+	b.pipe(func(runner *benchttp.Runner) {
+		if runner.Request == nil {
+			runner.Request = &http.Request{}
+		}
+		runner.Request.Method = v
+	})
+}
+
+func (b *Builder) SetRequestURL(v *url.URL) {
+	b.pipe(func(runner *benchttp.Runner) {
+		if runner.Request == nil {
+			runner.Request = &http.Request{}
+		}
+		runner.Request.URL = v
+	})
+}
+
+func (b *Builder) SetRequestHeader(v http.Header) {
+	b.SetRequestHeaderFunc(func(_ http.Header) http.Header {
+		return v
+	})
+}
+
+func (b *Builder) SetRequestHeaderFunc(f func(prev http.Header) http.Header) {
+	b.pipe(func(runner *benchttp.Runner) {
+		if runner.Request == nil {
+			runner.Request = &http.Request{}
+		}
+		runner.Request.Header = f(runner.Request.Header)
+	})
+}
+
+func (b *Builder) SetRequestBody(v io.ReadCloser) {
+	b.pipe(func(runner *benchttp.Runner) {
+		if runner.Request == nil {
+			runner.Request = &http.Request{}
+		}
+		runner.Request.Body = v
+	})
+}
+
+func (b *Builder) SetRequests(v int) {
+	b.pipe(func(runner *benchttp.Runner) {
+		runner.Requests = v
+	})
+}
+
+func (b *Builder) SetConcurrency(v int) {
+	b.pipe(func(runner *benchttp.Runner) {
+		runner.Concurrency = v
+	})
+}
+
+func (b *Builder) SetInterval(v time.Duration) {
+	b.pipe(func(runner *benchttp.Runner) {
+		runner.Interval = v
+	})
+}
+
+func (b *Builder) SetRequestTimeout(v time.Duration) {
+	b.pipe(func(runner *benchttp.Runner) {
+		runner.RequestTimeout = v
+	})
+}
+
+func (b *Builder) SetGlobalTimeout(v time.Duration) {
+	b.pipe(func(runner *benchttp.Runner) {
+		runner.GlobalTimeout = v
+	})
+}
+
+func (b *Builder) SetTests(v []benchttp.TestCase) {
+	b.pipe(func(runner *benchttp.Runner) {
+		runner.Tests = v
+	})
+}
+
+func (b *Builder) AddTests(v ...benchttp.TestCase) {
+	b.pipe(func(runner *benchttp.Runner) {
+		runner.Tests = append(runner.Tests, v...)
+	})
+}
+
+func (b *Builder) pipe(modifier func(runner *benchttp.Runner)) {
+	if modifier == nil {
+		panicInternal("Builder.pipe", "call with nil modifier")
+	}
+	if b.modifier == nil {
+		b.modifier = modifier
+		return
+	}
+	applyPreviousModifier := b.modifier
+	b.modifier = func(dst *benchttp.Runner) {
+		applyPreviousModifier(dst)
+		modifier(dst)
+	}
+}
diff --git a/configio/builder_test.go b/configio/builder_test.go
new file mode 100644
index 0000000..6dc95ee
--- /dev/null
+++ b/configio/builder_test.go
@@ -0,0 +1,148 @@
+package configio_test
+
+import (
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/benchttp/sdk/benchttp"
+	"github.com/benchttp/sdk/benchttptest"
+	"github.com/benchttp/sdk/configio"
+)
+
+func TestBuilder_WriteJSON(t *testing.T) {
+	in := []byte(`{"runner":{"requests": 5}}`)
+	dest := benchttp.Runner{Requests: 0, Concurrency: 2}
+	want := benchttp.Runner{Requests: 5, Concurrency: 2}
+
+	b := configio.Builder{}
+	if err := b.WriteJSON(in); err != nil {
+		t.Fatal(err)
+	}
+	b.Into(&dest)
+
+	benchttptest.AssertEqualRunners(t, want, dest)
+}
+
+func TestBuilder_WriteYAML(t *testing.T) {
+	in := []byte(`runner: { requests: 5 }`)
+	dest := benchttp.Runner{Requests: 0, Concurrency: 2}
+	want := benchttp.Runner{Requests: 5, Concurrency: 2}
+
+	b := configio.Builder{}
+	if err := b.WriteYAML(in); err != nil {
+		t.Fatal(err)
+	}
+	b.Into(&dest)
+
+	benchttptest.AssertEqualRunners(t, want, dest)
+}
+
+func TestBuilder_Set(t *testing.T) {
+	t.Run("basic fields", func(t *testing.T) {
+		want := benchttp.Runner{
+			Requests:       5,
+			Concurrency:    2,
+			Interval:       10 * time.Millisecond,
+			RequestTimeout: 1 * time.Second,
+			GlobalTimeout:  10 * time.Second,
+		}
+
+		b := configio.Builder{}
+		b.SetRequests(want.Requests)
+		b.SetConcurrency(-1)
+		b.SetConcurrency(want.Concurrency)
+		b.SetInterval(want.Interval)
+		b.SetRequestTimeout(want.RequestTimeout)
+		b.SetGlobalTimeout(want.GlobalTimeout)
+
+		benchttptest.AssertEqualRunners(t, want, b.Runner())
+	})
+
+	t.Run("request", func(t *testing.T) {
+		want := benchttp.Runner{
+			Request: httptest.NewRequest("GET", "https://example.com", nil),
+		}
+
+		b := configio.Builder{}
+		b.SetRequest(want.Request)
+
+		benchttptest.AssertEqualRunners(t, want, b.Runner())
+	})
+
+	t.Run("request fields", func(t *testing.T) {
+		want := benchttp.Runner{
+			Request: &http.Request{
+				Method: "PUT",
+				URL:    mustParseRequestURI("https://example.com"),
+				Header: http.Header{
+					"API_KEY": []string{"abc"},
+					"Accept":  []string{"text/html", "application/json"},
+				},
+				Body: readcloser("hello"),
+			},
+		}
+
+		b := configio.Builder{}
+		b.SetRequestMethod(want.Request.Method)
+		b.SetRequestURL(want.Request.URL)
+		b.SetRequestHeader(http.Header{"API_KEY": []string{"abc"}})
+		b.SetRequestHeaderFunc(func(prev http.Header) http.Header {
+			prev.Add("Accept", "text/html")
+			prev.Add("Accept", "application/json")
+			return prev
+		})
+		b.SetRequestBody(readcloser("hello"))
+
+		benchttptest.AssertEqualRunners(t, want, b.Runner())
+	})
+
+	t.Run("test cases", func(t *testing.T) {
+		want := benchttp.Runner{
+			Tests: []benchttp.TestCase{
+				{
+					Name:      "maximum response time",
+					Field:     "ResponseTimes.Max",
+					Predicate: "LT",
+					Target:    100 * time.Millisecond,
+				},
+				{
+					Name:      "similar response times",
+					Field:     "ResponseTimes.StdDev",
+					Predicate: "LTE",
+					Target:    20 * time.Millisecond,
+				},
+				{
+					Name:      "100% availability",
+					Field:     "RequestFailureCount",
+					Predicate: "EQ",
+					Target:    0,
+				},
+			},
+		}
+
+		b := configio.Builder{}
+		b.SetTests([]benchttp.TestCase{want.Tests[0]})
+		b.AddTests(want.Tests[1:]...)
+
+		benchttptest.AssertEqualRunners(t, want, b.Runner())
+	})
+}
+
+// helpers
+
+func mustParseRequestURI(s string) *url.URL {
+	u, err := url.ParseRequestURI(s)
+	if err != nil {
+		panic("mustParseRequestURI: " + err.Error())
+	}
+	return u
+}
+
+func readcloser(s string) io.ReadCloser {
+	return io.NopCloser(strings.NewReader(s))
+}
diff --git a/configio/representation.go b/configio/representation.go
index c668f0d..e13f2db 100644
--- a/configio/representation.go
+++ b/configio/representation.go
@@ -49,6 +49,10 @@ type Representation struct {
 	} `yaml:"tests" json:"tests"`
 }
 
+func (repr Representation) validate() error {
+	return repr.Into(&benchttp.Runner{})
+}
+
 // Into parses the Representation receiver as a benchttp.Runner
 // and stores any non-nil field value into the corresponding field
 // of dst.

From 9b8780039665a0a08ad4e6cbf01c60c275137e36 Mon Sep 17 00:00:00 2001
From: Gregory Albouy <gregoryalbouy75@gmail.com>
Date: Sun, 6 Nov 2022 17:44:16 +0100
Subject: [PATCH 02/10] doc(configio): write ExampleBuilder example

---
 configio/example_test.go | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)
 create mode 100644 configio/example_test.go

diff --git a/configio/example_test.go b/configio/example_test.go
new file mode 100644
index 0000000..4efe5b2
--- /dev/null
+++ b/configio/example_test.go
@@ -0,0 +1,40 @@
+package configio_test
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/benchttp/sdk/benchttp"
+	"github.com/benchttp/sdk/configio"
+)
+
+var jsonConfig = []byte(
+	`{"request": {"method": "GET", "url": "https://example.com"}}`,
+)
+
+var yamlConfig = []byte(
+	`{request: {method: PUT}, runner: {requests: 42}}`,
+)
+
+func ExampleBuilder() {
+	runner := benchttp.Runner{Requests: -1, Concurrency: 3}
+
+	b := configio.Builder{}
+	_ = b.WriteJSON(jsonConfig)
+	_ = b.WriteYAML(yamlConfig)
+	b.SetInterval(100 * time.Millisecond)
+
+	b.Into(&runner)
+
+	// Output:
+	// PUT
+	// https://example.com
+	// 42
+	// 3
+	// 100ms
+	fmt.Println(runner.Request.Method)
+	fmt.Println(runner.Request.URL)
+	fmt.Println(runner.Requests)
+	fmt.Println(runner.Concurrency)
+	fmt.Println(runner.Interval)
+}

From 528dd50ab2bbbf410b8e6c3be3e387b02e5e4119 Mon Sep 17 00:00:00 2001
From: Gregory Albouy <gregoryalbouy75@gmail.com>
Date: Sun, 6 Nov 2022 19:08:54 +0100
Subject: [PATCH 03/10] tmp: benchmark pipe vs append implementations for
 configio.Builder

---
 configio/builder_append.go         | 151 +++++++++++++++++++++++++++++
 configio/builder_append_test.go    | 131 +++++++++++++++++++++++++
 configio/builder_benchmark_test.go |  75 ++++++++++++++
 3 files changed, 357 insertions(+)
 create mode 100644 configio/builder_append.go
 create mode 100644 configio/builder_append_test.go
 create mode 100644 configio/builder_benchmark_test.go

diff --git a/configio/builder_append.go b/configio/builder_append.go
new file mode 100644
index 0000000..d067cd1
--- /dev/null
+++ b/configio/builder_append.go
@@ -0,0 +1,151 @@
+package configio
+
+import (
+	"io"
+	"net/http"
+	"net/url"
+	"time"
+
+	"github.com/benchttp/sdk/benchttp"
+)
+
+type Builder_append struct { // nolint:revive
+	modifiers []func(*benchttp.Runner)
+}
+
+func (b *Builder_append) WriteJSON(in []byte) error {
+	return b.decodeAndWrite(in, FormatJSON)
+}
+
+func (b *Builder_append) WriteYAML(in []byte) error {
+	return b.decodeAndWrite(in, FormatYAML)
+}
+
+func (b *Builder_append) decodeAndWrite(in []byte, format Format) error {
+	repr := Representation{}
+	if err := DecoderOf(format, in).Decode(&repr); err != nil {
+		return err
+	}
+	if err := repr.validate(); err != nil {
+		return err
+	}
+	b.append(func(dst *benchttp.Runner) {
+		_ = repr.Into(dst)
+	})
+	return nil
+}
+
+func (b *Builder_append) Runner() benchttp.Runner {
+	runner := benchttp.Runner{}
+	b.into(&runner)
+	return runner
+}
+
+func (b *Builder_append) Into(dst *benchttp.Runner) {
+	b.into(dst)
+}
+
+func (b *Builder_append) into(dst *benchttp.Runner) {
+	for _, modify := range b.modifiers {
+		modify(dst)
+	}
+}
+
+// setters
+
+func (b *Builder_append) SetRequest(r *http.Request) {
+	b.append(func(runner *benchttp.Runner) {
+		runner.Request = r
+	})
+}
+
+func (b *Builder_append) SetRequestMethod(v string) {
+	b.append(func(runner *benchttp.Runner) {
+		if runner.Request == nil {
+			runner.Request = &http.Request{}
+		}
+		runner.Request.Method = v
+	})
+}
+
+func (b *Builder_append) SetRequestURL(v *url.URL) {
+	b.append(func(runner *benchttp.Runner) {
+		if runner.Request == nil {
+			runner.Request = &http.Request{}
+		}
+		runner.Request.URL = v
+	})
+}
+
+func (b *Builder_append) SetRequestHeader(v http.Header) {
+	b.SetRequestHeaderFunc(func(_ http.Header) http.Header {
+		return v
+	})
+}
+
+func (b *Builder_append) SetRequestHeaderFunc(f func(prev http.Header) http.Header) {
+	b.append(func(runner *benchttp.Runner) {
+		if runner.Request == nil {
+			runner.Request = &http.Request{}
+		}
+		runner.Request.Header = f(runner.Request.Header)
+	})
+}
+
+func (b *Builder_append) SetRequestBody(v io.ReadCloser) {
+	b.append(func(runner *benchttp.Runner) {
+		if runner.Request == nil {
+			runner.Request = &http.Request{}
+		}
+		runner.Request.Body = v
+	})
+}
+
+func (b *Builder_append) SetRequests(v int) {
+	b.append(func(runner *benchttp.Runner) {
+		runner.Requests = v
+	})
+}
+
+func (b *Builder_append) SetConcurrency(v int) {
+	b.append(func(runner *benchttp.Runner) {
+		runner.Concurrency = v
+	})
+}
+
+func (b *Builder_append) SetInterval(v time.Duration) {
+	b.append(func(runner *benchttp.Runner) {
+		runner.Interval = v
+	})
+}
+
+func (b *Builder_append) SetRequestTimeout(v time.Duration) {
+	b.append(func(runner *benchttp.Runner) {
+		runner.RequestTimeout = v
+	})
+}
+
+func (b *Builder_append) SetGlobalTimeout(v time.Duration) {
+	b.append(func(runner *benchttp.Runner) {
+		runner.GlobalTimeout = v
+	})
+}
+
+func (b *Builder_append) SetTests(v []benchttp.TestCase) {
+	b.append(func(runner *benchttp.Runner) {
+		runner.Tests = v
+	})
+}
+
+func (b *Builder_append) AddTests(v ...benchttp.TestCase) {
+	b.append(func(runner *benchttp.Runner) {
+		runner.Tests = append(runner.Tests, v...)
+	})
+}
+
+func (b *Builder_append) append(modifier func(runner *benchttp.Runner)) {
+	if modifier == nil {
+		panicInternal("Builder.append", "call with nil modifier")
+	}
+	b.modifiers = append(b.modifiers, modifier)
+}
diff --git a/configio/builder_append_test.go b/configio/builder_append_test.go
new file mode 100644
index 0000000..0a6d2ab
--- /dev/null
+++ b/configio/builder_append_test.go
@@ -0,0 +1,131 @@
+package configio_test
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"github.com/benchttp/sdk/benchttp"
+	"github.com/benchttp/sdk/benchttptest"
+	"github.com/benchttp/sdk/configio"
+)
+
+func TestBuilder_append_WriteJSON(t *testing.T) {
+	in := []byte(`{"runner":{"requests": 5}}`)
+	dest := benchttp.Runner{Requests: 0, Concurrency: 2}
+	want := benchttp.Runner{Requests: 5, Concurrency: 2}
+
+	b := configio.Builder_append{}
+	if err := b.WriteJSON(in); err != nil {
+		t.Fatal(err)
+	}
+	b.Into(&dest)
+
+	benchttptest.AssertEqualRunners(t, want, dest)
+}
+
+func TestBuilder_append_WriteYAML(t *testing.T) {
+	in := []byte(`runner: { requests: 5 }`)
+	dest := benchttp.Runner{Requests: 0, Concurrency: 2}
+	want := benchttp.Runner{Requests: 5, Concurrency: 2}
+
+	b := configio.Builder_append{}
+	if err := b.WriteYAML(in); err != nil {
+		t.Fatal(err)
+	}
+	b.Into(&dest)
+
+	benchttptest.AssertEqualRunners(t, want, dest)
+}
+
+func TestBuilder_append_Set(t *testing.T) {
+	t.Run("basic fields", func(t *testing.T) {
+		want := benchttp.Runner{
+			Requests:       5,
+			Concurrency:    2,
+			Interval:       10 * time.Millisecond,
+			RequestTimeout: 1 * time.Second,
+			GlobalTimeout:  10 * time.Second,
+		}
+
+		b := configio.Builder_append{}
+		b.SetRequests(want.Requests)
+		b.SetConcurrency(-1)
+		b.SetConcurrency(want.Concurrency)
+		b.SetInterval(want.Interval)
+		b.SetRequestTimeout(want.RequestTimeout)
+		b.SetGlobalTimeout(want.GlobalTimeout)
+
+		benchttptest.AssertEqualRunners(t, want, b.Runner())
+	})
+
+	t.Run("request", func(t *testing.T) {
+		want := benchttp.Runner{
+			Request: httptest.NewRequest("GET", "https://example.com", nil),
+		}
+
+		b := configio.Builder_append{}
+		b.SetRequest(want.Request)
+
+		benchttptest.AssertEqualRunners(t, want, b.Runner())
+	})
+
+	t.Run("request fields", func(t *testing.T) {
+		want := benchttp.Runner{
+			Request: &http.Request{
+				Method: "PUT",
+				URL:    mustParseRequestURI("https://example.com"),
+				Header: http.Header{
+					"API_KEY": []string{"abc"},
+					"Accept":  []string{"text/html", "application/json"},
+				},
+				Body: readcloser("hello"),
+			},
+		}
+
+		b := configio.Builder_append{}
+		b.SetRequestMethod(want.Request.Method)
+		b.SetRequestURL(want.Request.URL)
+		b.SetRequestHeader(http.Header{"API_KEY": []string{"abc"}})
+		b.SetRequestHeaderFunc(func(prev http.Header) http.Header {
+			prev.Add("Accept", "text/html")
+			prev.Add("Accept", "application/json")
+			return prev
+		})
+		b.SetRequestBody(readcloser("hello"))
+
+		benchttptest.AssertEqualRunners(t, want, b.Runner())
+	})
+
+	t.Run("test cases", func(t *testing.T) {
+		want := benchttp.Runner{
+			Tests: []benchttp.TestCase{
+				{
+					Name:      "maximum response time",
+					Field:     "ResponseTimes.Max",
+					Predicate: "LT",
+					Target:    100 * time.Millisecond,
+				},
+				{
+					Name:      "similar response times",
+					Field:     "ResponseTimes.StdDev",
+					Predicate: "LTE",
+					Target:    20 * time.Millisecond,
+				},
+				{
+					Name:      "100% availability",
+					Field:     "RequestFailureCount",
+					Predicate: "EQ",
+					Target:    0,
+				},
+			},
+		}
+
+		b := configio.Builder_append{}
+		b.SetTests([]benchttp.TestCase{want.Tests[0]})
+		b.AddTests(want.Tests[1:]...)
+
+		benchttptest.AssertEqualRunners(t, want, b.Runner())
+	})
+}
diff --git a/configio/builder_benchmark_test.go b/configio/builder_benchmark_test.go
new file mode 100644
index 0000000..f4431c9
--- /dev/null
+++ b/configio/builder_benchmark_test.go
@@ -0,0 +1,75 @@
+package configio_test
+
+import (
+	"strconv"
+	"testing"
+
+	"github.com/benchttp/sdk/configio"
+)
+
+/*
+Output:
+
+Running tool: /Users/greg/sdk/go1.17.6/bin/go test -benchmem -run=^$ -bench ^(BenchmarkBuilder)$ github.com/benchttp/sdk/configio
+
+goos: darwin
+goarch: amd64
+pkg: github.com/benchttp/sdk/configio
+cpu: Intel(R) Core(TM) i5-8279U CPU @ 2.40GHz
+BenchmarkBuilder/setters/Builder_pipe-8                 12966073                97.47 ns/op           40 B/op          2 allocs/op
+BenchmarkBuilder/setters/Builder_append-8               21533343                81.65 ns/op           64 B/op          1 allocs/op
+BenchmarkBuilder/build/Builder_pipe_100-8                3044132               396.5 ns/op            96 B/op          1 allocs/op
+BenchmarkBuilder/build/Builder_append_100-8              5413728               222.9 ns/op            96 B/op          1 allocs/op
+BenchmarkBuilder/build/Builder_pipe_10000-8                25195             41284 ns/op              96 B/op          1 allocs/op
+BenchmarkBuilder/build/Builder_append_10000-8              71463             16838 ns/op              96 B/op          1 allocs/op
+BenchmarkBuilder/build/Builder_pipe_1000000-8                156           6993338 ns/op              96 B/op          1 allocs/op
+BenchmarkBuilder/build/Builder_append_1000000-8              451           2730270 ns/op              96 B/op          1 allocs/op
+*/
+func BenchmarkBuilder(b *testing.B) {
+	b.Run("setters", func(b *testing.B) {
+		b.Run("Builder_pipe", func(b *testing.B) {
+			builder := configio.Builder{}
+			for i := 0; i < b.N; i++ {
+				builder.SetConcurrency(100)
+			}
+		})
+		b.Run("Builder_append", func(b *testing.B) {
+			builder := configio.Builder_append{}
+			for i := 0; i < b.N; i++ {
+				builder.SetConcurrency(100)
+			}
+		})
+	})
+
+	b.Run("build", func(b *testing.B) {
+		for _, iter := range []int{100, 10_000, 1_000_000} {
+			b.Run("Builder_pipe_"+strconv.Itoa(iter), func(b *testing.B) {
+				builder := configio.Builder{}
+				setupBuilder(b, &builder, iter)
+				for i := 0; i < b.N; i++ {
+					_ = builder.Runner()
+				}
+			})
+			b.Run("Builder_append_"+strconv.Itoa(iter), func(b *testing.B) {
+				builder := configio.Builder_append{}
+				setupBuilder(b, &builder, iter)
+				for i := 0; i < b.N; i++ {
+					_ = builder.Runner()
+				}
+			})
+		}
+	})
+}
+
+func setupBuilder(
+	b *testing.B,
+	builder interface{ SetConcurrency(int) },
+	iter int,
+) {
+	b.Helper()
+	values := []int{-100, 100}
+	for i := 0; i < iter; i++ {
+		builder.SetConcurrency(values[i%2])
+	}
+	b.ResetTimer()
+}

From b3baa391778bfa6d0c8d2c17241215a24c518bb5 Mon Sep 17 00:00:00 2001
From: Gregory Albouy <gregoryalbouy75@gmail.com>
Date: Sun, 6 Nov 2022 19:09:29 +0100
Subject: [PATCH 04/10] Revert "tmp: benchmark pipe vs append implementations
 for configio.Builder"

This reverts commit 731547e2925a323b1c568c3c440e0aab637c58fd.
---
 configio/builder_append.go         | 151 -----------------------------
 configio/builder_append_test.go    | 131 -------------------------
 configio/builder_benchmark_test.go |  75 --------------
 3 files changed, 357 deletions(-)
 delete mode 100644 configio/builder_append.go
 delete mode 100644 configio/builder_append_test.go
 delete mode 100644 configio/builder_benchmark_test.go

diff --git a/configio/builder_append.go b/configio/builder_append.go
deleted file mode 100644
index d067cd1..0000000
--- a/configio/builder_append.go
+++ /dev/null
@@ -1,151 +0,0 @@
-package configio
-
-import (
-	"io"
-	"net/http"
-	"net/url"
-	"time"
-
-	"github.com/benchttp/sdk/benchttp"
-)
-
-type Builder_append struct { // nolint:revive
-	modifiers []func(*benchttp.Runner)
-}
-
-func (b *Builder_append) WriteJSON(in []byte) error {
-	return b.decodeAndWrite(in, FormatJSON)
-}
-
-func (b *Builder_append) WriteYAML(in []byte) error {
-	return b.decodeAndWrite(in, FormatYAML)
-}
-
-func (b *Builder_append) decodeAndWrite(in []byte, format Format) error {
-	repr := Representation{}
-	if err := DecoderOf(format, in).Decode(&repr); err != nil {
-		return err
-	}
-	if err := repr.validate(); err != nil {
-		return err
-	}
-	b.append(func(dst *benchttp.Runner) {
-		_ = repr.Into(dst)
-	})
-	return nil
-}
-
-func (b *Builder_append) Runner() benchttp.Runner {
-	runner := benchttp.Runner{}
-	b.into(&runner)
-	return runner
-}
-
-func (b *Builder_append) Into(dst *benchttp.Runner) {
-	b.into(dst)
-}
-
-func (b *Builder_append) into(dst *benchttp.Runner) {
-	for _, modify := range b.modifiers {
-		modify(dst)
-	}
-}
-
-// setters
-
-func (b *Builder_append) SetRequest(r *http.Request) {
-	b.append(func(runner *benchttp.Runner) {
-		runner.Request = r
-	})
-}
-
-func (b *Builder_append) SetRequestMethod(v string) {
-	b.append(func(runner *benchttp.Runner) {
-		if runner.Request == nil {
-			runner.Request = &http.Request{}
-		}
-		runner.Request.Method = v
-	})
-}
-
-func (b *Builder_append) SetRequestURL(v *url.URL) {
-	b.append(func(runner *benchttp.Runner) {
-		if runner.Request == nil {
-			runner.Request = &http.Request{}
-		}
-		runner.Request.URL = v
-	})
-}
-
-func (b *Builder_append) SetRequestHeader(v http.Header) {
-	b.SetRequestHeaderFunc(func(_ http.Header) http.Header {
-		return v
-	})
-}
-
-func (b *Builder_append) SetRequestHeaderFunc(f func(prev http.Header) http.Header) {
-	b.append(func(runner *benchttp.Runner) {
-		if runner.Request == nil {
-			runner.Request = &http.Request{}
-		}
-		runner.Request.Header = f(runner.Request.Header)
-	})
-}
-
-func (b *Builder_append) SetRequestBody(v io.ReadCloser) {
-	b.append(func(runner *benchttp.Runner) {
-		if runner.Request == nil {
-			runner.Request = &http.Request{}
-		}
-		runner.Request.Body = v
-	})
-}
-
-func (b *Builder_append) SetRequests(v int) {
-	b.append(func(runner *benchttp.Runner) {
-		runner.Requests = v
-	})
-}
-
-func (b *Builder_append) SetConcurrency(v int) {
-	b.append(func(runner *benchttp.Runner) {
-		runner.Concurrency = v
-	})
-}
-
-func (b *Builder_append) SetInterval(v time.Duration) {
-	b.append(func(runner *benchttp.Runner) {
-		runner.Interval = v
-	})
-}
-
-func (b *Builder_append) SetRequestTimeout(v time.Duration) {
-	b.append(func(runner *benchttp.Runner) {
-		runner.RequestTimeout = v
-	})
-}
-
-func (b *Builder_append) SetGlobalTimeout(v time.Duration) {
-	b.append(func(runner *benchttp.Runner) {
-		runner.GlobalTimeout = v
-	})
-}
-
-func (b *Builder_append) SetTests(v []benchttp.TestCase) {
-	b.append(func(runner *benchttp.Runner) {
-		runner.Tests = v
-	})
-}
-
-func (b *Builder_append) AddTests(v ...benchttp.TestCase) {
-	b.append(func(runner *benchttp.Runner) {
-		runner.Tests = append(runner.Tests, v...)
-	})
-}
-
-func (b *Builder_append) append(modifier func(runner *benchttp.Runner)) {
-	if modifier == nil {
-		panicInternal("Builder.append", "call with nil modifier")
-	}
-	b.modifiers = append(b.modifiers, modifier)
-}
diff --git a/configio/builder_append_test.go b/configio/builder_append_test.go
deleted file mode 100644
index 0a6d2ab..0000000
--- a/configio/builder_append_test.go
+++ /dev/null
@@ -1,131 +0,0 @@
-package configio_test
-
-import (
-	"net/http"
-	"net/http/httptest"
-	"testing"
-	"time"
-
-	"github.com/benchttp/sdk/benchttp"
-	"github.com/benchttp/sdk/benchttptest"
-	"github.com/benchttp/sdk/configio"
-)
-
-func TestBuilder_append_WriteJSON(t *testing.T) {
-	in := []byte(`{"runner":{"requests": 5}}`)
-	dest := benchttp.Runner{Requests: 0, Concurrency: 2}
-	want := benchttp.Runner{Requests: 5, Concurrency: 2}
-
-	b := configio.Builder_append{}
-	if err := b.WriteJSON(in); err != nil {
-		t.Fatal(err)
-	}
-	b.Into(&dest)
-
-	benchttptest.AssertEqualRunners(t, want, dest)
-}
-
-func TestBuilder_append_WriteYAML(t *testing.T) {
-	in := []byte(`runner: { requests: 5 }`)
-	dest := benchttp.Runner{Requests: 0, Concurrency: 2}
-	want := benchttp.Runner{Requests: 5, Concurrency: 2}
-
-	b := configio.Builder_append{}
-	if err := b.WriteYAML(in); err != nil {
-		t.Fatal(err)
-	}
-	b.Into(&dest)
-
-	benchttptest.AssertEqualRunners(t, want, dest)
-}
-
-func TestBuilder_append_Set(t *testing.T) {
-	t.Run("basic fields", func(t *testing.T) {
-		want := benchttp.Runner{
-			Requests:       5,
-			Concurrency:    2,
-			Interval:       10 * time.Millisecond,
-			RequestTimeout: 1 * time.Second,
-			GlobalTimeout:  10 * time.Second,
-		}
-
-		b := configio.Builder_append{}
-		b.SetRequests(want.Requests)
-		b.SetConcurrency(-1)
-		b.SetConcurrency(want.Concurrency)
-		b.SetInterval(want.Interval)
-		b.SetRequestTimeout(want.RequestTimeout)
-		b.SetGlobalTimeout(want.GlobalTimeout)
-
-		benchttptest.AssertEqualRunners(t, want, b.Runner())
-	})
-
-	t.Run("request", func(t *testing.T) {
-		want := benchttp.Runner{
-			Request: httptest.NewRequest("GET", "https://example.com", nil),
-		}
-
-		b := configio.Builder_append{}
-		b.SetRequest(want.Request)
-
-		benchttptest.AssertEqualRunners(t, want, b.Runner())
-	})
-
-	t.Run("request fields", func(t *testing.T) {
-		want := benchttp.Runner{
-			Request: &http.Request{
-				Method: "PUT",
-				URL:    mustParseRequestURI("https://example.com"),
-				Header: http.Header{
-					"API_KEY": []string{"abc"},
-					"Accept":  []string{"text/html", "application/json"},
-				},
-				Body: readcloser("hello"),
-			},
-		}
-
-		b := configio.Builder_append{}
-		b.SetRequestMethod(want.Request.Method)
-		b.SetRequestURL(want.Request.URL)
-		b.SetRequestHeader(http.Header{"API_KEY": []string{"abc"}})
-		b.SetRequestHeaderFunc(func(prev http.Header) http.Header {
-			prev.Add("Accept", "text/html")
-			prev.Add("Accept", "application/json")
-			return prev
-		})
-		b.SetRequestBody(readcloser("hello"))
-
-		benchttptest.AssertEqualRunners(t, want, b.Runner())
-	})
-
-	t.Run("test cases", func(t *testing.T) {
-		want := benchttp.Runner{
-			Tests: []benchttp.TestCase{
-				{
-					Name:      "maximum response time",
-					Field:     "ResponseTimes.Max",
-					Predicate: "LT",
-					Target:    100 * time.Millisecond,
-				},
-				{
-					Name:      "similar response times",
-					Field:     "ResponseTimes.StdDev",
-					Predicate: "LTE",
-					Target:    20 * time.Millisecond,
-				},
-				{
-					Name:      "100% availability",
-					Field:     "RequestFailureCount",
-					Predicate: "EQ",
-					Target:    0,
-				},
-			},
-		}
-
-		b := configio.Builder_append{}
-		b.SetTests([]benchttp.TestCase{want.Tests[0]})
-		b.AddTests(want.Tests[1:]...)
-
-		benchttptest.AssertEqualRunners(t, want, b.Runner())
-	})
-}
diff --git a/configio/builder_benchmark_test.go b/configio/builder_benchmark_test.go
deleted file mode 100644
index f4431c9..0000000
--- a/configio/builder_benchmark_test.go
+++ /dev/null
@@ -1,75 +0,0 @@
-package configio_test
-
-import (
-	"strconv"
-	"testing"
-
-	"github.com/benchttp/sdk/configio"
-)
-
-/*
-Output:
-
-Running tool: /Users/greg/sdk/go1.17.6/bin/go test -benchmem -run=^$ -bench ^(BenchmarkBuilder)$ github.com/benchttp/sdk/configio
-
-goos: darwin
-goarch: amd64
-pkg: github.com/benchttp/sdk/configio
-cpu: Intel(R) Core(TM) i5-8279U CPU @ 2.40GHz
-BenchmarkBuilder/setters/Builder_pipe-8                 12966073                97.47 ns/op           40 B/op          2 allocs/op
-BenchmarkBuilder/setters/Builder_append-8               21533343                81.65 ns/op           64 B/op          1 allocs/op
-BenchmarkBuilder/build/Builder_pipe_100-8                3044132               396.5 ns/op            96 B/op          1 allocs/op
-BenchmarkBuilder/build/Builder_append_100-8              5413728               222.9 ns/op            96 B/op          1 allocs/op
-BenchmarkBuilder/build/Builder_pipe_10000-8                25195             41284 ns/op              96 B/op          1 allocs/op
-BenchmarkBuilder/build/Builder_append_10000-8              71463             16838 ns/op              96 B/op          1 allocs/op
-BenchmarkBuilder/build/Builder_pipe_1000000-8                156           6993338 ns/op              96 B/op          1 allocs/op
-BenchmarkBuilder/build/Builder_append_1000000-8              451           2730270 ns/op              96 B/op          1 allocs/op
-*/
-func BenchmarkBuilder(b *testing.B) {
-	b.Run("setters", func(b *testing.B) {
-		b.Run("Builder_pipe", func(b *testing.B) {
-			builder := configio.Builder{}
-			for i := 0; i < b.N; i++ {
-				builder.SetConcurrency(100)
-			}
-		})
-		b.Run("Builder_append", func(b *testing.B) {
-			builder := configio.Builder_append{}
-			for i := 0; i < b.N; i++ {
-				builder.SetConcurrency(100)
-			}
-		})
-	})
-
-	b.Run("build", func(b *testing.B) {
-		for _, iter := range []int{100, 10_000, 1_000_000} {
-			b.Run("Builder_pipe_"+strconv.Itoa(iter), func(b *testing.B) {
-				builder := configio.Builder{}
-				setupBuilder(b, &builder, iter)
-				for i := 0; i < b.N; i++ {
-					_ = builder.Runner()
-				}
-			})
-			b.Run("Builder_append_"+strconv.Itoa(iter), func(b *testing.B) {
-				builder := configio.Builder_append{}
-				setupBuilder(b, &builder, iter)
-				for i := 0; i < b.N; i++ {
-					_ = builder.Runner()
-				}
-			})
-		}
-	})
-}
-
-func setupBuilder(
-	b *testing.B,
-	builder interface{ SetConcurrency(int) },
-	iter int,
-) {
-	b.Helper()
-	values := []int{-100, 100}
-	for i := 0; i < iter; i++ {
-		builder.SetConcurrency(values[i%2])
-	}
-	b.ResetTimer()
-}

From a849d2ed01f1eb1979b29ccbf67dc0ea355acd37 Mon Sep 17 00:00:00 2001
From: Gregory Albouy <gregoryalbouy75@gmail.com>
Date: Sun, 6 Nov 2022 19:42:44 +0100
Subject: [PATCH 05/10] perf(configio): use an array of modifiers for Builder

Previous benchmarks showed 2.5x better performance over piped modifier.
---
 configio/builder.go | 48 ++++++++++++++++++---------------------------
 1 file changed, 19 insertions(+), 29 deletions(-)

diff --git a/configio/builder.go b/configio/builder.go
index ad15021..b306f4f 100644
--- a/configio/builder.go
+++ b/configio/builder.go
@@ -10,8 +10,7 @@ import (
 )
 
 type Builder struct {
-	// TODO: benchmark this vs []func(*benchttp.Runner)
-	modifier func(*benchttp.Runner)
+	modifiers []func(*benchttp.Runner)
 }
 
 func (b *Builder) WriteJSON(in []byte) error {
@@ -30,7 +29,7 @@ func (b *Builder) decodeAndWrite(in []byte, format Format) error {
 	if err := repr.validate(); err != nil {
 		return err
 	}
-	b.pipe(func(dst *benchttp.Runner) {
+	b.append(func(dst *benchttp.Runner) {
 		_ = repr.Into(dst)
 	})
 	return nil
@@ -47,22 +46,21 @@ func (b *Builder) Into(dst *benchttp.Runner) {
 }
 
 func (b *Builder) into(dst *benchttp.Runner) {
-	if b.modifier == nil {
-		return
+	for _, modify := range b.modifiers {
+		modify(dst)
 	}
-	b.modifier(dst)
 }
 
 // setters
 
 func (b *Builder) SetRequest(r *http.Request) {
-	b.pipe(func(runner *benchttp.Runner) {
+	b.append(func(runner *benchttp.Runner) {
 		runner.Request = r
 	})
 }
 
 func (b *Builder) SetRequestMethod(v string) {
-	b.pipe(func(runner *benchttp.Runner) {
+	b.append(func(runner *benchttp.Runner) {
 		if runner.Request == nil {
 			runner.Request = &http.Request{}
 		}
@@ -71,7 +69,7 @@ func (b *Builder) SetRequestMethod(v string) {
 }
 
 func (b *Builder) SetRequestURL(v *url.URL) {
-	b.pipe(func(runner *benchttp.Runner) {
+	b.append(func(runner *benchttp.Runner) {
 		if runner.Request == nil {
 			runner.Request = &http.Request{}
 		}
@@ -86,7 +84,7 @@ func (b *Builder) SetRequestHeader(v http.Header) {
 }
 
 func (b *Builder) SetRequestHeaderFunc(f func(prev http.Header) http.Header) {
-	b.pipe(func(runner *benchttp.Runner) {
+	b.append(func(runner *benchttp.Runner) {
 		if runner.Request == nil {
 			runner.Request = &http.Request{}
 		}
@@ -95,7 +93,7 @@ func (b *Builder) SetRequestHeaderFunc(f func(prev http.Header) http.Header) {
 }
 
 func (b *Builder) SetRequestBody(v io.ReadCloser) {
-	b.pipe(func(runner *benchttp.Runner) {
+	b.append(func(runner *benchttp.Runner) {
 		if runner.Request == nil {
 			runner.Request = &http.Request{}
 		}
@@ -104,58 +102,50 @@ func (b *Builder) SetRequestBody(v io.ReadCloser) {
 }
 
 func (b *Builder) SetRequests(v int) {
-	b.pipe(func(runner *benchttp.Runner) {
+	b.append(func(runner *benchttp.Runner) {
 		runner.Requests = v
 	})
 }
 
 func (b *Builder) SetConcurrency(v int) {
-	b.pipe(func(runner *benchttp.Runner) {
+	b.append(func(runner *benchttp.Runner) {
 		runner.Concurrency = v
 	})
 }
 
 func (b *Builder) SetInterval(v time.Duration) {
-	b.pipe(func(runner *benchttp.Runner) {
+	b.append(func(runner *benchttp.Runner) {
 		runner.Interval = v
 	})
 }
 
 func (b *Builder) SetRequestTimeout(v time.Duration) {
-	b.pipe(func(runner *benchttp.Runner) {
+	b.append(func(runner *benchttp.Runner) {
 		runner.RequestTimeout = v
 	})
 }
 
 func (b *Builder) SetGlobalTimeout(v time.Duration) {
-	b.pipe(func(runner *benchttp.Runner) {
+	b.append(func(runner *benchttp.Runner) {
 		runner.GlobalTimeout = v
 	})
 }
 
 func (b *Builder) SetTests(v []benchttp.TestCase) {
-	b.pipe(func(runner *benchttp.Runner) {
+	b.append(func(runner *benchttp.Runner) {
 		runner.Tests = v
 	})
 }
 
 func (b *Builder) AddTests(v ...benchttp.TestCase) {
-	b.pipe(func(runner *benchttp.Runner) {
+	b.append(func(runner *benchttp.Runner) {
 		runner.Tests = append(runner.Tests, v...)
 	})
 }
 
-func (b *Builder) pipe(modifier func(runner *benchttp.Runner)) {
+func (b *Builder) append(modifier func(runner *benchttp.Runner)) {
 	if modifier == nil {
-		panicInternal("Builder.pipe", "call with nil modifier")
-	}
-	if b.modifier == nil {
-		b.modifier = modifier
-		return
-	}
-	applyPreviousModifier := b.modifier
-	b.modifier = func(dst *benchttp.Runner) {
-		applyPreviousModifier(dst)
-		modifier(dst)
+		panicInternal("Builder.append", "call with nil modifier")
 	}
+	b.modifiers = append(b.modifiers, modifier)
 }

From 54d5ecc68537a0aa81cef78b296b68a924911b5a Mon Sep 17 00:00:00 2001
From: Gregory Albouy <gregoryalbouy75@gmail.com>
Date: Sun, 6 Nov 2022 20:12:54 +0100
Subject: [PATCH 06/10] refactor(configio): Builder renamings

- Builder.Into -> Builder.Mutate
- Builder.modifiers -> Builder.mutations
---
 configio/builder.go      | 16 ++++++----------
 configio/builder_test.go |  4 ++--
 configio/example_test.go |  2 +-
 3 files changed, 9 insertions(+), 13 deletions(-)

diff --git a/configio/builder.go b/configio/builder.go
index b306f4f..a541896 100644
--- a/configio/builder.go
+++ b/configio/builder.go
@@ -10,7 +10,7 @@ import (
 )
 
 type Builder struct {
-	modifiers []func(*benchttp.Runner)
+	mutations []func(*benchttp.Runner)
 }
 
 func (b *Builder) WriteJSON(in []byte) error {
@@ -37,17 +37,13 @@ func (b *Builder) decodeAndWrite(in []byte, format Format) error {
 
 func (b *Builder) Runner() benchttp.Runner {
 	runner := benchttp.Runner{}
-	b.into(&runner)
+	b.Mutate(&runner)
 	return runner
 }
 
-func (b *Builder) Into(dst *benchttp.Runner) {
-	b.into(dst)
-}
-
-func (b *Builder) into(dst *benchttp.Runner) {
-	for _, modify := range b.modifiers {
-		modify(dst)
+func (b *Builder) Mutate(dst *benchttp.Runner) {
+	for _, mutate := range b.mutations {
+		mutate(dst)
 	}
 }
 
@@ -147,5 +143,5 @@ func (b *Builder) append(modifier func(runner *benchttp.Runner)) {
 	if modifier == nil {
 		panicInternal("Builder.append", "call with nil modifier")
 	}
-	b.modifiers = append(b.modifiers, modifier)
+	b.mutations = append(b.mutations, modifier)
 }
diff --git a/configio/builder_test.go b/configio/builder_test.go
index 6dc95ee..4123882 100644
--- a/configio/builder_test.go
+++ b/configio/builder_test.go
@@ -23,7 +23,7 @@ func TestBuilder_WriteJSON(t *testing.T) {
 	if err := b.WriteJSON(in); err != nil {
 		t.Fatal(err)
 	}
-	b.Into(&dest)
+	b.Mutate(&dest)
 
 	benchttptest.AssertEqualRunners(t, want, dest)
 }
@@ -37,7 +37,7 @@ func TestBuilder_WriteYAML(t *testing.T) {
 	if err := b.WriteYAML(in); err != nil {
 		t.Fatal(err)
 	}
-	b.Into(&dest)
+	b.Mutate(&dest)
 
 	benchttptest.AssertEqualRunners(t, want, dest)
 }
diff --git a/configio/example_test.go b/configio/example_test.go
index 4efe5b2..b2f86dc 100644
--- a/configio/example_test.go
+++ b/configio/example_test.go
@@ -24,7 +24,7 @@ func ExampleBuilder() {
 	_ = b.WriteYAML(yamlConfig)
 	b.SetInterval(100 * time.Millisecond)
 
-	b.Into(&runner)
+	b.Mutate(&runner)
 
 	// Output:
 	// PUT

From 0637323a444aa2d9c1ea6fe0e10af439314449bf Mon Sep 17 00:00:00 2001
From: Gregory Albouy <gregoryalbouy75@gmail.com>
Date: Sun, 6 Nov 2022 20:44:56 +0100
Subject: [PATCH 07/10] doc(configio): add documenting comments for Builder

---
 configio/builder.go | 42 +++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 41 insertions(+), 1 deletion(-)

diff --git a/configio/builder.go b/configio/builder.go
index a541896..92efe91 100644
--- a/configio/builder.go
+++ b/configio/builder.go
@@ -9,14 +9,25 @@ import (
 	"github.com/benchttp/sdk/benchttp"
 )
 
+// A Builder is used to incrementally build a benchttp.Runner
+// using Set and Write methods.
+// The zero value is ready to use.
 type Builder struct {
 	mutations []func(*benchttp.Runner)
 }
 
+// WriteJSON decodes the input bytes as a JSON benchttp configuration
+// and appends the resulting modifier to the builder.
+// It returns any encountered during the decoding process or if the
+// decoded configuration is invalid.
 func (b *Builder) WriteJSON(in []byte) error {
 	return b.decodeAndWrite(in, FormatJSON)
 }
 
+// WriteYAML decodes the input bytes as a YAML benchttp configuration
+// and appends the resulting modifier to the builder.
+// It returns any encountered during the decoding process or if the
+// decoded configuration is invalid.
 func (b *Builder) WriteYAML(in []byte) error {
 	return b.decodeAndWrite(in, FormatYAML)
 }
@@ -26,21 +37,29 @@ func (b *Builder) decodeAndWrite(in []byte, format Format) error {
 	if err := DecoderOf(format, in).Decode(&repr); err != nil {
 		return err
 	}
+	// early check for invalid configuration
 	if err := repr.validate(); err != nil {
 		return err
 	}
 	b.append(func(dst *benchttp.Runner) {
-		_ = repr.Into(dst)
+		// err is already checked via repr.validate(), so nil is expected.
+		if err := repr.Into(dst); err != nil {
+			panicInternal("Builder.decodeAndWrite", "unexpected error: "+err.Error())
+		}
 	})
 	return nil
 }
 
+// Runner successively applies the Builder's mutations
+// to a zero benchttp.Runner and returns it.
 func (b *Builder) Runner() benchttp.Runner {
 	runner := benchttp.Runner{}
 	b.Mutate(&runner)
 	return runner
 }
 
+// Mutate successively applies the Builder's mutations
+// to the benchttp.Runner value pointed to by dst.
 func (b *Builder) Mutate(dst *benchttp.Runner) {
 	for _, mutate := range b.mutations {
 		mutate(dst)
@@ -49,12 +68,14 @@ func (b *Builder) Mutate(dst *benchttp.Runner) {
 
 // setters
 
+// SetRequest adds a mutation that sets a runner's request to r.
 func (b *Builder) SetRequest(r *http.Request) {
 	b.append(func(runner *benchttp.Runner) {
 		runner.Request = r
 	})
 }
 
+// SetRequestMethod adds a mutation that sets a runner's request method to v.
 func (b *Builder) SetRequestMethod(v string) {
 	b.append(func(runner *benchttp.Runner) {
 		if runner.Request == nil {
@@ -64,6 +85,7 @@ func (b *Builder) SetRequestMethod(v string) {
 	})
 }
 
+// SetRequestURL adds a mutation that sets a runner's request URL to v.
 func (b *Builder) SetRequestURL(v *url.URL) {
 	b.append(func(runner *benchttp.Runner) {
 		if runner.Request == nil {
@@ -73,12 +95,15 @@ func (b *Builder) SetRequestURL(v *url.URL) {
 	})
 }
 
+// SetRequestHeader adds a mutation that sets a runner's request header to v.
 func (b *Builder) SetRequestHeader(v http.Header) {
 	b.SetRequestHeaderFunc(func(_ http.Header) http.Header {
 		return v
 	})
 }
 
+// SetRequestHeaderFunc adds a mutation that sets a runner's request header
+// to the result of calling f with its current request header.
 func (b *Builder) SetRequestHeaderFunc(f func(prev http.Header) http.Header) {
 	b.append(func(runner *benchttp.Runner) {
 		if runner.Request == nil {
@@ -88,6 +113,7 @@ func (b *Builder) SetRequestHeaderFunc(f func(prev http.Header) http.Header) {
 	})
 }
 
+// SetRequestBody adds a mutation that sets a runner's request body to v.
 func (b *Builder) SetRequestBody(v io.ReadCloser) {
 	b.append(func(runner *benchttp.Runner) {
 		if runner.Request == nil {
@@ -97,42 +123,56 @@ func (b *Builder) SetRequestBody(v io.ReadCloser) {
 	})
 }
 
+// SetRequests adds a mutation that sets a runner's
+// Requests field to v.
 func (b *Builder) SetRequests(v int) {
 	b.append(func(runner *benchttp.Runner) {
 		runner.Requests = v
 	})
 }
 
+// SetConcurrency adds a mutation that sets a runner's
+// Concurrency field to v.
 func (b *Builder) SetConcurrency(v int) {
 	b.append(func(runner *benchttp.Runner) {
 		runner.Concurrency = v
 	})
 }
 
+// SetInterval adds a mutation that sets a runner's
+// Interval field to v.
 func (b *Builder) SetInterval(v time.Duration) {
 	b.append(func(runner *benchttp.Runner) {
 		runner.Interval = v
 	})
 }
 
+// SetRequestTimeout adds a mutation that sets a runner's
+// RequestTimeout field to v.
 func (b *Builder) SetRequestTimeout(v time.Duration) {
 	b.append(func(runner *benchttp.Runner) {
 		runner.RequestTimeout = v
 	})
 }
 
+// SetGlobalTimeout adds a mutation that sets a runner's
+// GlobalTimeout field to v.
 func (b *Builder) SetGlobalTimeout(v time.Duration) {
 	b.append(func(runner *benchttp.Runner) {
 		runner.GlobalTimeout = v
 	})
 }
 
+// SetTests adds a mutation that sets a runner's
+// Tests field to v.
 func (b *Builder) SetTests(v []benchttp.TestCase) {
 	b.append(func(runner *benchttp.Runner) {
 		runner.Tests = v
 	})
 }
 
+// SetTests adds a mutation that appends the given benchttp.TestCases
+// to a runner's Tests field.
 func (b *Builder) AddTests(v ...benchttp.TestCase) {
 	b.append(func(runner *benchttp.Runner) {
 		runner.Tests = append(runner.Tests, v...)

From 313f8c4623f4329d9a3a5d5d37ff856cf6f41deb Mon Sep 17 00:00:00 2001
From: Gregory Albouy <gregoryalbouy75@gmail.com>
Date: Sun, 6 Nov 2022 22:06:30 +0100
Subject: [PATCH 08/10] feat(configio): make Representation private

- configio.Representation -> configio.representation
- make all representation methods private
---
 configio/builder.go        |  4 ++--
 configio/decoder.go        |  2 +-
 configio/file.go           |  4 ++--
 configio/json.go           |  8 ++++----
 configio/representation.go | 22 +++++++++++-----------
 configio/yaml.go           |  8 ++++----
 6 files changed, 24 insertions(+), 24 deletions(-)

diff --git a/configio/builder.go b/configio/builder.go
index 92efe91..ffd3a15 100644
--- a/configio/builder.go
+++ b/configio/builder.go
@@ -33,7 +33,7 @@ func (b *Builder) WriteYAML(in []byte) error {
 }
 
 func (b *Builder) decodeAndWrite(in []byte, format Format) error {
-	repr := Representation{}
+	repr := representation{}
 	if err := DecoderOf(format, in).Decode(&repr); err != nil {
 		return err
 	}
@@ -43,7 +43,7 @@ func (b *Builder) decodeAndWrite(in []byte, format Format) error {
 	}
 	b.append(func(dst *benchttp.Runner) {
 		// err is already checked via repr.validate(), so nil is expected.
-		if err := repr.Into(dst); err != nil {
+		if err := repr.parseAndMutate(dst); err != nil {
 			panicInternal("Builder.decodeAndWrite", "unexpected error: "+err.Error())
 		}
 	})
diff --git a/configio/decoder.go b/configio/decoder.go
index 0014f70..4045ec5 100644
--- a/configio/decoder.go
+++ b/configio/decoder.go
@@ -8,7 +8,7 @@ import (
 )
 
 type Decoder interface {
-	Decode(dst *Representation) error
+	Decode(dst *representation) error
 	DecodeRunner(dst *benchttp.Runner) error
 }
 
diff --git a/configio/file.go b/configio/file.go
index f0aff7d..d2fb01c 100644
--- a/configio/file.go
+++ b/configio/file.go
@@ -49,7 +49,7 @@ func UnmarshalFile(filename string, dst *benchttp.Runner) error {
 type file struct {
 	prev *file
 	path string
-	repr Representation
+	repr representation
 }
 
 // decodeAll reads f.path as a file and decodes it into f.repr.
@@ -122,7 +122,7 @@ func (f file) seen(p string) bool {
 // reprs returns a slice of Representation, starting with the receiver
 // and ending with the last child.
 func (f file) reprs() representations {
-	reprs := []Representation{f.repr}
+	reprs := []representation{f.repr}
 	if f.prev != nil {
 		reprs = append(reprs, f.prev.reprs()...)
 	}
diff --git a/configio/json.go b/configio/json.go
index debd94e..de31c1e 100644
--- a/configio/json.go
+++ b/configio/json.go
@@ -13,7 +13,7 @@ import (
 
 // UnmarshalJSON parses the JSON-encoded data and stores the result
 // in the Representation pointed to by dst.
-func UnmarshalJSON(in []byte, dst *Representation) error {
+func UnmarshalJSON(in []byte, dst *representation) error {
 	dec := NewJSONDecoder(bytes.NewReader(in))
 	return dec.Decode(dst)
 }
@@ -34,7 +34,7 @@ func NewJSONDecoder(r io.Reader) JSONDecoder {
 
 // Decode reads the next JSON-encoded value from its input
 // and stores it in the Representation pointed to by dst.
-func (d JSONDecoder) Decode(dst *Representation) error {
+func (d JSONDecoder) Decode(dst *representation) error {
 	decoder := json.NewDecoder(d.r)
 	decoder.DisallowUnknownFields()
 	return d.handleError(decoder.Decode(dst))
@@ -43,11 +43,11 @@ func (d JSONDecoder) Decode(dst *Representation) error {
 // Decode reads the next JSON-encoded value from its input
 // and stores it in the benchttp.Runner pointed to by dst.
 func (d JSONDecoder) DecodeRunner(dst *benchttp.Runner) error {
-	repr := Representation{}
+	repr := representation{}
 	if err := d.Decode(&repr); err != nil {
 		return err
 	}
-	return repr.Into(dst)
+	return repr.parseAndMutate(dst)
 }
 
 // handleError handles an error from package json,
diff --git a/configio/representation.go b/configio/representation.go
index e13f2db..6097283 100644
--- a/configio/representation.go
+++ b/configio/representation.go
@@ -14,12 +14,12 @@ import (
 	"github.com/benchttp/sdk/internal/errorutil"
 )
 
-// Representation is a raw data model for formatted runner config (json, yaml).
+// representation is a raw data model for formatted runner config (json, yaml).
 // It serves as a receiver for unmarshaling processes and for that reason
 // its types are kept simple (certain types are incompatible with certain
 // unmarshalers).
 // It exposes a method Unmarshal to convert its values into a runner.Config.
-type Representation struct {
+type representation struct {
 	Extends *string `yaml:"extends" json:"extends"`
 
 	Request struct {
@@ -49,14 +49,14 @@ type Representation struct {
 	} `yaml:"tests" json:"tests"`
 }
 
-func (repr Representation) validate() error {
-	return repr.Into(&benchttp.Runner{})
+func (repr representation) validate() error {
+	return repr.parseAndMutate(&benchttp.Runner{})
 }
 
-// Into parses the Representation receiver as a benchttp.Runner
+// parseAndMutate parses the Representation receiver as a benchttp.Runner
 // and stores any non-nil field value into the corresponding field
 // of dst.
-func (repr Representation) Into(dst *benchttp.Runner) error {
+func (repr representation) parseAndMutate(dst *benchttp.Runner) error {
 	if err := repr.parseRequestInto(dst); err != nil {
 		return err
 	}
@@ -66,7 +66,7 @@ func (repr Representation) Into(dst *benchttp.Runner) error {
 	return repr.parseTestsInto(dst)
 }
 
-func (repr Representation) parseRequestInto(dst *benchttp.Runner) error {
+func (repr representation) parseRequestInto(dst *benchttp.Runner) error {
 	if dst.Request == nil {
 		dst.Request = &http.Request{}
 	}
@@ -103,7 +103,7 @@ func (repr Representation) parseRequestInto(dst *benchttp.Runner) error {
 	return nil
 }
 
-func (repr Representation) parseRunnerInto(dst *benchttp.Runner) error {
+func (repr representation) parseRunnerInto(dst *benchttp.Runner) error {
 	if requests := repr.Runner.Requests; requests != nil {
 		dst.Requests = *requests
 	}
@@ -139,7 +139,7 @@ func (repr Representation) parseRunnerInto(dst *benchttp.Runner) error {
 	return nil
 }
 
-func (repr Representation) parseTestsInto(dst *benchttp.Runner) error {
+func (repr representation) parseTestsInto(dst *benchttp.Runner) error {
 	testSuite := repr.Tests
 	if len(testSuite) == 0 {
 		return nil
@@ -254,7 +254,7 @@ func requireConfigFields(fields map[string]interface{}) error {
 	return nil
 }
 
-type representations []Representation
+type representations []representation
 
 // mergeInto successively parses the given representations into dst.
 //
@@ -265,7 +265,7 @@ func (reprs representations) mergeInto(dst *benchttp.Runner) error {
 	}
 
 	for _, repr := range reprs {
-		if err := repr.Into(dst); err != nil {
+		if err := repr.parseAndMutate(dst); err != nil {
 			return errorutil.WithDetails(ErrFileParse, err)
 		}
 	}
diff --git a/configio/yaml.go b/configio/yaml.go
index d1130c3..7b13b90 100644
--- a/configio/yaml.go
+++ b/configio/yaml.go
@@ -14,7 +14,7 @@ import (
 
 // UnmarshalYAML parses the YAML-encoded data and stores the result
 // in the Representation pointed to by dst.
-func UnmarshalYAML(in []byte, dst *Representation) error {
+func UnmarshalYAML(in []byte, dst *representation) error {
 	dec := NewYAMLDecoder(bytes.NewReader(in))
 	return dec.Decode(dst)
 }
@@ -35,7 +35,7 @@ func NewYAMLDecoder(r io.Reader) YAMLDecoder {
 
 // Decode reads the next YAML-encoded value from its input
 // and stores it in the Representation pointed to by dst.
-func (d YAMLDecoder) Decode(dst *Representation) error {
+func (d YAMLDecoder) Decode(dst *representation) error {
 	decoder := yaml.NewDecoder(d.r)
 	decoder.KnownFields(true)
 	return d.handleError(decoder.Decode(dst))
@@ -44,11 +44,11 @@ func (d YAMLDecoder) Decode(dst *Representation) error {
 // Decode reads the next YAML-encoded value from its input
 // and stores it in the benchttp.Runner pointed to by dst.
 func (d YAMLDecoder) DecodeRunner(dst *benchttp.Runner) error {
-	repr := Representation{}
+	repr := representation{}
 	if err := d.Decode(&repr); err != nil {
 		return err
 	}
-	return repr.Into(dst)
+	return repr.parseAndMutate(dst)
 }
 
 // handleError handles a raw yaml decoder.Decode error, filters it,

From 39fb4a61b356f38eba5fb3c13fd9c92ba88914c3 Mon Sep 17 00:00:00 2001
From: Gregory Albouy <gregoryalbouy75@gmail.com>
Date: Sun, 6 Nov 2022 22:25:49 +0100
Subject: [PATCH 09/10] feat(configio): remove public references to
 representation

- remove Decode methods from interface Decoder and its implementations
- rename DecodeRunner methods to Decode
- remove UnmarshalXXXX functions
- rename UnmarshalXXXXRunner functions to UnmarshalXXXX
---
 configio/builder.go   |  2 +-
 configio/decoder.go   | 18 +++++++++++++-----
 configio/file.go      |  2 +-
 configio/json.go      | 39 +++++++++++++++++----------------------
 configio/json_test.go |  4 ++--
 configio/yaml.go      | 39 +++++++++++++++++----------------------
 configio/yaml_test.go |  2 +-
 7 files changed, 52 insertions(+), 54 deletions(-)

diff --git a/configio/builder.go b/configio/builder.go
index ffd3a15..bb7d08e 100644
--- a/configio/builder.go
+++ b/configio/builder.go
@@ -34,7 +34,7 @@ func (b *Builder) WriteYAML(in []byte) error {
 
 func (b *Builder) decodeAndWrite(in []byte, format Format) error {
 	repr := representation{}
-	if err := DecoderOf(format, in).Decode(&repr); err != nil {
+	if err := decoderOf(format, in).decodeRepr(&repr); err != nil {
 		return err
 	}
 	// early check for invalid configuration
diff --git a/configio/decoder.go b/configio/decoder.go
index 4045ec5..41ca421 100644
--- a/configio/decoder.go
+++ b/configio/decoder.go
@@ -7,11 +7,6 @@ import (
 	"github.com/benchttp/sdk/benchttp"
 )
 
-type Decoder interface {
-	Decode(dst *representation) error
-	DecodeRunner(dst *benchttp.Runner) error
-}
-
 type Format string
 
 const (
@@ -19,9 +14,22 @@ const (
 	FormatYAML Format = "yaml"
 )
 
+type Decoder interface {
+	Decode(dst *benchttp.Runner) error
+}
+
 // DecoderOf returns the appropriate Decoder for the given Format.
 // It panics if the format is not a Format declared in configio.
 func DecoderOf(format Format, in []byte) Decoder {
+	return decoderOf(format, in)
+}
+
+type decoder interface {
+	Decoder
+	decodeRepr(dst *representation) error
+}
+
+func decoderOf(format Format, in []byte) decoder {
 	r := bytes.NewReader(in)
 	switch format {
 	case FormatYAML:
diff --git a/configio/file.go b/configio/file.go
index d2fb01c..8a73d1e 100644
--- a/configio/file.go
+++ b/configio/file.go
@@ -88,7 +88,7 @@ func (f *file) decode() (err error) {
 		return err
 	}
 
-	if err := DecoderOf(ext, b).Decode(&f.repr); err != nil {
+	if err := decoderOf(ext, b).decodeRepr(&f.repr); err != nil {
 		return errorutil.WithDetails(ErrFileParse, f.path, err)
 	}
 
diff --git a/configio/json.go b/configio/json.go
index de31c1e..9d83a11 100644
--- a/configio/json.go
+++ b/configio/json.go
@@ -11,45 +11,40 @@ import (
 	"github.com/benchttp/sdk/benchttp"
 )
 
-// UnmarshalJSON parses the JSON-encoded data and stores the result
-// in the Representation pointed to by dst.
-func UnmarshalJSON(in []byte, dst *representation) error {
-	dec := NewJSONDecoder(bytes.NewReader(in))
-	return dec.Decode(dst)
-}
+// JSONDecoder implements Decoder
+type JSONDecoder struct{ r io.Reader }
+
+var _ decoder = (*JSONDecoder)(nil)
 
-// UnmarshalJSONRunner parses the JSON-encoded data and stores the result
+// UnmarshalJSON parses the JSON-encoded data and stores the result
 // in the benchttp.Runner pointed to by dst.
-func UnmarshalJSONRunner(in []byte, dst *benchttp.Runner) error {
+func UnmarshalJSON(in []byte, dst *benchttp.Runner) error {
 	dec := NewJSONDecoder(bytes.NewReader(in))
-	return dec.DecodeRunner(dst)
+	return dec.Decode(dst)
 }
 
-// JSONDecoder implements Decoder
-type JSONDecoder struct{ r io.Reader }
-
 func NewJSONDecoder(r io.Reader) JSONDecoder {
 	return JSONDecoder{r: r}
 }
 
-// Decode reads the next JSON-encoded value from its input
-// and stores it in the Representation pointed to by dst.
-func (d JSONDecoder) Decode(dst *representation) error {
-	decoder := json.NewDecoder(d.r)
-	decoder.DisallowUnknownFields()
-	return d.handleError(decoder.Decode(dst))
-}
-
 // Decode reads the next JSON-encoded value from its input
 // and stores it in the benchttp.Runner pointed to by dst.
-func (d JSONDecoder) DecodeRunner(dst *benchttp.Runner) error {
+func (d JSONDecoder) Decode(dst *benchttp.Runner) error {
 	repr := representation{}
-	if err := d.Decode(&repr); err != nil {
+	if err := d.decodeRepr(&repr); err != nil {
 		return err
 	}
 	return repr.parseAndMutate(dst)
 }
 
+// decodeRepr reads the next JSON-encoded value from its input
+// and stores it in the Representation pointed to by dst.
+func (d JSONDecoder) decodeRepr(dst *representation) error {
+	decoder := json.NewDecoder(d.r)
+	decoder.DisallowUnknownFields()
+	return d.handleError(decoder.Decode(dst))
+}
+
 // handleError handles an error from package json,
 // transforms it into a user-friendly standardized format
 // and returns the resulting error.
diff --git a/configio/json_test.go b/configio/json_test.go
index c04bba2..d21a98b 100644
--- a/configio/json_test.go
+++ b/configio/json_test.go
@@ -57,7 +57,7 @@ func TestMarshalJSON(t *testing.T) {
 	for _, tc := range testcases {
 		t.Run(tc.name, func(t *testing.T) {
 			gotRunner := benchttp.DefaultRunner()
-			gotError := configio.UnmarshalJSONRunner(tc.input, &gotRunner)
+			gotError := configio.UnmarshalJSON(tc.input, &gotRunner)
 
 			if !tc.isValidRunner(benchttp.DefaultRunner(), gotRunner) {
 				t.Errorf("unexpected runner:\n%+v", gotRunner)
@@ -103,7 +103,7 @@ func TestJSONDecoder(t *testing.T) {
 				runner := benchttp.Runner{}
 				decoder := configio.NewJSONDecoder(bytes.NewReader(tc.in))
 
-				gotErr := decoder.DecodeRunner(&runner)
+				gotErr := decoder.Decode(&runner)
 
 				if tc.exp == "" {
 					if gotErr != nil {
diff --git a/configio/yaml.go b/configio/yaml.go
index 7b13b90..9bc604b 100644
--- a/configio/yaml.go
+++ b/configio/yaml.go
@@ -12,45 +12,40 @@ import (
 	"github.com/benchttp/sdk/benchttp"
 )
 
-// UnmarshalYAML parses the YAML-encoded data and stores the result
-// in the Representation pointed to by dst.
-func UnmarshalYAML(in []byte, dst *representation) error {
-	dec := NewYAMLDecoder(bytes.NewReader(in))
-	return dec.Decode(dst)
-}
+// YAMLDecoder implements Decoder
+type YAMLDecoder struct{ r io.Reader }
+
+var _ decoder = (*YAMLDecoder)(nil)
 
-// UnmarshalYAMLRunner parses the YAML-encoded data and stores the result
+// UnmarshalYAML parses the YAML-encoded data and stores the result
 // in the benchttp.Runner pointed to by dst.
-func UnmarshalYAMLRunner(in []byte, dst *benchttp.Runner) error {
+func UnmarshalYAML(in []byte, dst *benchttp.Runner) error {
 	dec := NewYAMLDecoder(bytes.NewReader(in))
-	return dec.DecodeRunner(dst)
+	return dec.Decode(dst)
 }
 
-// YAMLDecoder implements Decoder
-type YAMLDecoder struct{ r io.Reader }
-
 func NewYAMLDecoder(r io.Reader) YAMLDecoder {
 	return YAMLDecoder{r: r}
 }
 
-// Decode reads the next YAML-encoded value from its input
-// and stores it in the Representation pointed to by dst.
-func (d YAMLDecoder) Decode(dst *representation) error {
-	decoder := yaml.NewDecoder(d.r)
-	decoder.KnownFields(true)
-	return d.handleError(decoder.Decode(dst))
-}
-
 // Decode reads the next YAML-encoded value from its input
 // and stores it in the benchttp.Runner pointed to by dst.
-func (d YAMLDecoder) DecodeRunner(dst *benchttp.Runner) error {
+func (d YAMLDecoder) Decode(dst *benchttp.Runner) error {
 	repr := representation{}
-	if err := d.Decode(&repr); err != nil {
+	if err := d.decodeRepr(&repr); err != nil {
 		return err
 	}
 	return repr.parseAndMutate(dst)
 }
 
+// decodeRepr reads the next YAML-encoded value from its input
+// and stores it in the Representation pointed to by dst.
+func (d YAMLDecoder) decodeRepr(dst *representation) error {
+	decoder := yaml.NewDecoder(d.r)
+	decoder.KnownFields(true)
+	return d.handleError(decoder.Decode(dst))
+}
+
 // handleError handles a raw yaml decoder.Decode error, filters it,
 // and return the resulting error.
 func (d YAMLDecoder) handleError(err error) error {
diff --git a/configio/yaml_test.go b/configio/yaml_test.go
index 2f191cf..4bff966 100644
--- a/configio/yaml_test.go
+++ b/configio/yaml_test.go
@@ -69,7 +69,7 @@ func TestYAMLDecoder(t *testing.T) {
 				runner := benchttp.Runner{}
 				decoder := configio.NewYAMLDecoder(bytes.NewReader(tc.in))
 
-				gotErr := decoder.DecodeRunner(&runner)
+				gotErr := decoder.Decode(&runner)
 
 				if tc.expErr == nil {
 					if gotErr != nil {

From da00b0bf8da66ab52f147224dddd59d46a12c7c1 Mon Sep 17 00:00:00 2001
From: Gregory Albouy <gregoryalbouy75@gmail.com>
Date: Tue, 28 Mar 2023 23:49:03 +0200
Subject: [PATCH 10/10] refactor(configio): rename builder methods

Write -> Decode
---
 configio/builder.go      | 16 ++++++++--------
 configio/builder_test.go |  4 ++--
 configio/example_test.go |  4 ++--
 3 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/configio/builder.go b/configio/builder.go
index bb7d08e..400ba95 100644
--- a/configio/builder.go
+++ b/configio/builder.go
@@ -16,23 +16,23 @@ type Builder struct {
 	mutations []func(*benchttp.Runner)
 }
 
-// WriteJSON decodes the input bytes as a JSON benchttp configuration
+// DecodeJSON decodes the input bytes as a JSON benchttp configuration
 // and appends the resulting modifier to the builder.
 // It returns any encountered during the decoding process or if the
 // decoded configuration is invalid.
-func (b *Builder) WriteJSON(in []byte) error {
-	return b.decodeAndWrite(in, FormatJSON)
+func (b *Builder) DecodeJSON(in []byte) error {
+	return b.decode(in, FormatJSON)
 }
 
-// WriteYAML decodes the input bytes as a YAML benchttp configuration
+// DecodeYAML decodes the input bytes as a YAML benchttp configuration
 // and appends the resulting modifier to the builder.
 // It returns any encountered during the decoding process or if the
 // decoded configuration is invalid.
-func (b *Builder) WriteYAML(in []byte) error {
-	return b.decodeAndWrite(in, FormatYAML)
+func (b *Builder) DecodeYAML(in []byte) error {
+	return b.decode(in, FormatYAML)
 }
 
-func (b *Builder) decodeAndWrite(in []byte, format Format) error {
+func (b *Builder) decode(in []byte, format Format) error {
 	repr := representation{}
 	if err := decoderOf(format, in).decodeRepr(&repr); err != nil {
 		return err
@@ -44,7 +44,7 @@ func (b *Builder) decodeAndWrite(in []byte, format Format) error {
 	b.append(func(dst *benchttp.Runner) {
 		// err is already checked via repr.validate(), so nil is expected.
 		if err := repr.parseAndMutate(dst); err != nil {
-			panicInternal("Builder.decodeAndWrite", "unexpected error: "+err.Error())
+			panicInternal("Builder.decode", "unexpected error: "+err.Error())
 		}
 	})
 	return nil
diff --git a/configio/builder_test.go b/configio/builder_test.go
index 4123882..4665d0d 100644
--- a/configio/builder_test.go
+++ b/configio/builder_test.go
@@ -20,7 +20,7 @@ func TestBuilder_WriteJSON(t *testing.T) {
 	want := benchttp.Runner{Requests: 5, Concurrency: 2}
 
 	b := configio.Builder{}
-	if err := b.WriteJSON(in); err != nil {
+	if err := b.DecodeJSON(in); err != nil {
 		t.Fatal(err)
 	}
 	b.Mutate(&dest)
@@ -34,7 +34,7 @@ func TestBuilder_WriteYAML(t *testing.T) {
 	want := benchttp.Runner{Requests: 5, Concurrency: 2}
 
 	b := configio.Builder{}
-	if err := b.WriteYAML(in); err != nil {
+	if err := b.DecodeYAML(in); err != nil {
 		t.Fatal(err)
 	}
 	b.Mutate(&dest)
diff --git a/configio/example_test.go b/configio/example_test.go
index b2f86dc..e9f9f61 100644
--- a/configio/example_test.go
+++ b/configio/example_test.go
@@ -20,8 +20,8 @@ func ExampleBuilder() {
 	runner := benchttp.Runner{Requests: -1, Concurrency: 3}
 
 	b := configio.Builder{}
-	_ = b.WriteJSON(jsonConfig)
-	_ = b.WriteYAML(yamlConfig)
+	_ = b.DecodeJSON(jsonConfig)
+	_ = b.DecodeYAML(yamlConfig)
 	b.SetInterval(100 * time.Millisecond)
 
 	b.Mutate(&runner)