Remove the Postgres storage backend

.github/workflows/test.yml

@@ -9,18 +9,6 @@ on:
 jobs:
   test:
     runs-on: ubuntu-latest
-    services:
-      postgres:
-        image: postgres
-        env:
-          POSTGRES_PASSWORD: postgres
-        options: >-
-          --health-cmd pg_isready
-          --health-interval 10s
-          --health-timeout 5s
-          --health-retries 5
-        ports:
-          - 5432:5432
     steps:
       - uses: actions/checkout@v2
       - name: Set up Go
@@ -29,14 +17,7 @@ jobs:
           go-version: 1.25.x
       - name: Build
         run: go build -v ./...
-      - name: Create Table
-        run: |
-          psql postgres://postgres:postgres@localhost:5432/postgres -a -c '\i links.sql'
       - name: Test
-        env:
-          DATABASE_URL: postgres://postgres:postgres@localhost:5432/postgres
         run: go test -v ./...
       - name: Integration Test
-        env:
-          DATABASE_URL: postgres://postgres:postgres@localhost:5432/postgres
         run: ./test.sh

README.md

@@ -20,27 +20,25 @@ The server maintains a database of friendly names to URI redirect templates. For
 
 ## Storage
 
-The server picks its backing store from the environment, in this order:
+Links live in a SQLite database at `SQLITE_PATH`, which the server requires
+unless `--ephemeral` is passed for a throwaway in-memory store:
 
 | Condition | Store |
 | --- | --- |
 | `--ephemeral` | in-memory, discarded on exit |
-| `SQLITE_PATH` set | SQLite database at that path |
-| otherwise | Postgres at `DATABASE_URL` |
+| otherwise | SQLite database at `SQLITE_PATH` |
 
-SQLite keeps the whole link table in a single file, which is enough for this
-workload and avoids paying for a managed Postgres instance. The tradeoff is
-that the file lives on one volume, so the app is pinned to a single machine
-in a single region and there is no replication. Postgres remains supported:
-unset `SQLITE_PATH` to switch back.
+The whole link table is a single three-column relation, so a file on a
+mounted volume serves it comfortably and there is no database server to run.
+The tradeoff is that the file lives on one volume, pinning the app to a
+single machine in a single region with no replication.
 
-The schema is applied automatically when the SQLite database is opened, so a
-freshly provisioned volume needs no manual setup.
+The schema is applied automatically when the database is opened, so a freshly
+provisioned volume needs no manual setup.
 
 ### Backup and restore
 
-The client can dump the whole link database to a file and load it back,
-which doubles as the migration path between storage backends:
+The client can dump the whole link database to a file and load it back:
 
 ```
 $ client --export links-backup.json
@@ -52,23 +50,14 @@ returns, indented for readability. `--import` posts it back. Both accept `-`
 for stdout/stdin. Importing is additive and idempotent, so re-running it is
 safe.
 
-### Migrating Postgres to SQLite
-
-No database access is needed -- export from the running server, point it at
-an empty SQLite file, and import:
-
-1. `client --export links-backup.json` against the Postgres-backed server.
-2. Restart with `SQLITE_PATH` set, which creates and initializes an empty
-   database file.
-3. `client --import links-backup.json`.
-
-Keep the backup, and keep Postgres around until you're satisfied; unsetting
-`SQLITE_PATH` reverts to it with the original data untouched.
+Since the database is a single file, a volume snapshot works too -- but an
+export is portable, diffable, and does not depend on the host.
 
 ### Tests
 
-`./sqlite_test.sh` runs the full suite against SQLite and needs no database
-server. `./docker_test.sh` does the same against Postgres in a container.
+`go test ./...` covers the packages. `./test.sh` runs the end-to-end suite
+against a real server; it provisions its own SQLite file in a scratch
+directory, so it needs no database server and leaves nothing behind.
 
 ## REST API
 

cmd/links/links.go

@@ -16,7 +16,7 @@ import (
 )
 
 var (
-	ephemeral = flag.Bool("ephemeral", false, "If true, don't connect to DATABASE_URL and use in-memory storage")
+	ephemeral = flag.Bool("ephemeral", false, "If true, ignore SQLITE_PATH and use in-memory storage")
 )
 
 func main() {
@@ -46,31 +46,25 @@ func main() {
 	}
 	log.Printf("loaded keyset:\n%s", keyset)
 
-	// Storage precedence: -ephemeral wins, then SQLITE_PATH, then
-	// DATABASE_URL. Unsetting SQLITE_PATH reverts to Postgres.
+	// Storage is the SQLite database at SQLITE_PATH, unless -ephemeral asks
+	// for a throwaway in-memory store.
 	var store links.Store
 	ctx := context.Background()
-	sqlitePath := os.Getenv("SQLITE_PATH")
-	switch {
-	case *ephemeral:
+	if *ephemeral {
 		log.Printf("Running in ephemeral mode!")
 		store = links.NewMemStore()
-	case sqlitePath != "":
+	} else {
+		sqlitePath := os.Getenv("SQLITE_PATH")
+		if sqlitePath == "" {
+			log.Fatal("SQLITE_PATH environment variable must be set (or pass -ephemeral)")
+		}
 		sqliteStore, err := links.NewSQLiteStore(ctx, sqlitePath)
 		if err != nil {
 			log.Fatalf("links.NewSQLiteStore failed: %v", err)
 		}
 		log.Printf("Opened SQLite database at %s", sqlitePath)
 		store = sqliteStore
 		defer sqliteStore.Close()
-	default:
-		pgStore, err := links.NewPostgresStore(ctx, os.Getenv("DATABASE_URL"))
-		if err != nil {
-			log.Fatalf("links.NewPostgresStore failed: %v", err)
-		}
-		log.Print("Connected to Postgres")
-		store = pgStore
-		defer pgStore.Close()
 	}
 
 	skew := time.Duration(0)

dev/Dockerfile

@@ -1,4 +1,4 @@
-FROM golang:1.24-alpine AS builder
+FROM golang:1.25-alpine AS builder
 
 WORKDIR /app
 COPY go.mod .

dev/README.md

@@ -2,11 +2,10 @@
 
 This directory contains a docker compose file config that can be used to test locally end-to-end. Running `docker compose up` will:
 
-- Start postgres.
-- Start a links server on port 8080.
+- Start a links server on port 8080, backed by a SQLite database on the `links_data` volume.
 - Start a links web client on port 9090.
 
-Connect directly to the postgres instance using `postgres://postgres:postgres@localhost:15432/postgres`, or use the `psql.sh` script. Note that port is 15432 so that it doesn't conflict with any local postgres installation.
+The database persists across restarts in that volume. To start from an empty database, run `docker compose down -v`.
 
 Add a link to the server using the frontend at http://localhost:9090.
 

dev/docker-compose.yml

@@ -1,18 +1,4 @@
 services:
-  db:
-    image: postgres
-    user: postgres
-    volumes:
-      - ../links.sql:/docker-entrypoint-initdb.d/links.sql
-    ports:
-      - 15432:5432
-    environment:
-      POSTGRES_PASSWORD: postgres
-    healthcheck:
-      test: ["CMD-SHELL", "pg_isready"]
-      interval: 1s
-      timeout: 5s
-      retries: 5
   links:
     build:
       context: ..
@@ -21,10 +7,9 @@ services:
       - 8080:8080
     environment:
       LINKS_KEYSET: ${KEYSET}
-      DATABASE_URL: postgres://postgres:postgres@db:5432/postgres
-    depends_on:
-      db:
-        condition: service_healthy
+      SQLITE_PATH: /data/links.db
+    volumes:
+      - links_data:/data
   links-client:
     build:
       context: ..
@@ -37,3 +22,6 @@ services:
       LINKS_ADDR: http://links:8080
     depends_on:
       - links
+
+volumes:
+  links_data:

go.mod

@@ -4,7 +4,6 @@ go 1.25.0
 
 require (
 	github.com/go-chi/chi/v5 v5.3.1
-	github.com/jackc/pgx/v5 v5.10.0
 	github.com/skip2/go-qrcode v0.0.0-20200617195104-da1b6568686e
 	google.golang.org/protobuf v1.36.10
 	jdtw.dev/token v0.1.6
@@ -14,15 +13,11 @@ require (
 require (
 	github.com/dustin/go-humanize v1.0.1 // indirect
 	github.com/google/uuid v1.6.0 // indirect
-	github.com/jackc/pgpassfile v1.0.0 // indirect
-	github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 // indirect
-	github.com/jackc/puddle/v2 v2.2.2 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
 	github.com/ncruces/go-strftime v1.0.0 // indirect
 	github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec // indirect
 	golang.org/x/sync v0.22.0 // indirect
 	golang.org/x/sys v0.46.0 // indirect
-	golang.org/x/text v0.40.0 // indirect
 	modernc.org/libc v1.74.1 // indirect
 	modernc.org/mathutil v1.7.1 // indirect
 	modernc.org/memory v1.11.0 // indirect

go.sum

@@ -1,6 +1,3 @@
-github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
-github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/dustin/go-humanize v1.0.1 h1:GzkhY7T5VNhEkwH0PVJgjz+fX1rhBrR7pRT3mDkpeCY=
 github.com/dustin/go-humanize v1.0.1/go.mod h1:Mu1zIs6XwVuF/gI1OepvI0qD18qycQx+mFykh5fBlto=
 github.com/go-chi/chi/v5 v5.3.1 h1:3j4HZLGZQ3JpMCrPJF/Jl3mYJfWLKBfNJ6quurUGCf8=
@@ -13,46 +10,25 @@ github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
 github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/hashicorp/golang-lru/v2 v2.0.7 h1:a+bsQ5rvGLjzHuww6tVxozPZFVghXaHOwFs4luLUK2k=
 github.com/hashicorp/golang-lru/v2 v2.0.7/go.mod h1:QeFd9opnmA6QUJc5vARoKUSoFhyfM2/ZepoAG6RGpeM=
-github.com/jackc/pgpassfile v1.0.0 h1:/6Hmqy13Ss2zCq62VdNG8tM1wchn8zjSGOBJ6icpsIM=
-github.com/jackc/pgpassfile v1.0.0/go.mod h1:CEx0iS5ambNFdcRtxPj5JhEz+xB6uRky5eyVu/W2HEg=
-github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 h1:iCEnooe7UlwOQYpKFhBabPMi4aNAfoODPEFNiAnClxo=
-github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761/go.mod h1:5TJZWKEWniPve33vlWYSoGYefn3gLQRzjfDlhSJ9ZKM=
-github.com/jackc/pgx/v5 v5.10.0 h1:VhSvgU2jSli8o3AqIEOTJr7rZwAEUVo4E4XhR94Zfr0=
-github.com/jackc/pgx/v5 v5.10.0/go.mod h1:mal1tBGAFfLHvZzaYh77YS/eC6IX9OWbRV1QIIM0Jn4=
-github.com/jackc/puddle/v2 v2.2.2 h1:PR8nw+E/1w0GLuRFSmiioY6UooMp6KJv0/61nB7icHo=
-github.com/jackc/puddle/v2 v2.2.2/go.mod h1:vriiEXHvEE654aYKXXjOvZM39qJ0q+azkZFrfEOc3H4=
 github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
 github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
 github.com/ncruces/go-strftime v1.0.0 h1:HMFp8mLCTPp341M/ZnA4qaf7ZlsbTc+miZjCLOFAw7w=
 github.com/ncruces/go-strftime v1.0.0/go.mod h1:Fwc5htZGVVkseilnfgOVb9mKy6w1naJmn9CehxcKcls=
-github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
-github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec h1:W09IVJc94icq4NjY3clb7Lk8O1qJ8BdBEF8z0ibU0rE=
 github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec/go.mod h1:qqbHyh8v60DhA7CoWK5oRCqLrMHRGoxYCSS9EjAz6Eo=
 github.com/skip2/go-qrcode v0.0.0-20200617195104-da1b6568686e h1:MRM5ITcdelLK2j1vwZ3Je0FKVCfqOLp5zO6trqMLYs0=
 github.com/skip2/go-qrcode v0.0.0-20200617195104-da1b6568686e/go.mod h1:XV66xRDqSt+GTGFMVlhk3ULuV0y9ZmzeVGR4mloJI3M=
-github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
-github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
-github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
-github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
 golang.org/x/mod v0.37.0 h1:vF1DjpVEshcIqoEaauuHebaLk1O1forxjxBaVn884JQ=
 golang.org/x/mod v0.37.0/go.mod h1:m8S8VeM9r4dzDwjrKO0a1sZP3YjeMamRRlD+fmR2Q/0=
 golang.org/x/sync v0.22.0 h1:SZjpbeLmrCk4xhRSZFNZW5gFUeCeFgjekvI/+gfScek=
 golang.org/x/sync v0.22.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.46.0 h1:noSf2Fq6F8DBgS+LysIkx7rIExoNHJsxOAtPp4rthXw=
 golang.org/x/sys v0.46.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
-golang.org/x/text v0.40.0 h1:Ub2Z6/xjgF1WrYQz2nuITOEegKFtiIy+rieRJ5lHZKs=
-golang.org/x/text v0.40.0/go.mod h1:hpnzDAfGV753zIKo+wk3u1bVKCGPbrnF7+7LBF/UHVY=
 golang.org/x/tools v0.47.0 h1:7Kn5x/d1svx/PzryTsqeoZN4TZwqeH5pGWjefhLi/1Q=
 golang.org/x/tools v0.47.0/go.mod h1:dFHnyTvFWY212G+h7ZY4Vsp/K3U4/7W9TyVaAul8uCA=
 google.golang.org/protobuf v1.36.10 h1:AYd7cD/uASjIL6Q9LiTjz8JLcrh/88q5UObnmY3aOOE=
 google.golang.org/protobuf v1.36.10/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
-gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
-gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
-gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 jdtw.dev/token v0.1.6 h1:EzvBOo0s+O4cudJqZob1ynhyIjtWfS85Oxfk/b0iqP4=
 jdtw.dev/token v0.1.6/go.mod h1:qr+zsFbOixxkv7T5Jb7rar/5Gs2yhw27vyNX0Q7pBA4=
 modernc.org/cc/v4 v4.29.0 h1:CXgwL8cvxmyzBQZzbSl/6xFtMCryb6u8IOqDci39cgc=

pkg/links/bulk_test.go

@@ -190,7 +190,7 @@ func TestBulkPutRequiresAuth(t *testing.T) {
 }
 
 // Export then import must reproduce the original set exactly -- this is the
-// property the Postgres -> SQLite migration relies on.
+// property backup and restore relies on.
 func TestExportImportRoundTrip(t *testing.T) {
 	keyset, priv := tokentest.GenerateKey(t, "test")
 	ctx := context.Background()