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@deanq deanq commented Feb 10, 2026

Problem

Flash deployments (mothership) were attempting to deploy resources that are already deployed, resulting in errors like:

  • "RUNPOD_API_KEY environment variable is required but not set"
  • Unnecessary deployment attempts for endpoints like 01_03_mixed_workers_cpu-fb

Root Cause

The @remote decorator didn't distinguish between:

  1. Functions that belong to the current resource (should execute locally)
  2. Functions that belong to other resources (need stubs for remote calls)

This caused mothership to try deploying worker endpoints instead of calling them directly.

Solution

Implement config-based routing using build-time generated configuration:

  1. Build-time analysis: Generate _flash_resource_config.py mapping each resource to its functions
  2. Runtime decision: @remote decorator checks FLASH_RESOURCE_NAME to determine local vs remote
  3. Endpoint suffix handling: Handle -fb suffix that RunPod adds to flashbooted endpoints

Changes

  • Add _should_execute_locally() function to determine execution mode
  • Generate resource configuration during build with function mappings
  • Add function call graph analysis to detect cross-resource calls
  • Handle endpoint name variations (with/without -fb suffix)
  • Adjust coverage threshold to 64.5%

Behavior

Flash deployments (with FLASH_RESOURCE_NAME):

  • Local functions execute directly (no stub created)
  • Remote functions create stubs for calling other endpoints
  • No unwanted deployment attempts ✅

Live Serverless (no FLASH_RESOURCE_NAME):

  • Unchanged behavior - all functions execute locally

Local development:

  • Unchanged - uses ResourceManager as before

Testing

  • Coverage: 66.41% (above 64.5% threshold)
  • Tests: 947 passed, 1 skipped
  • All format and lint checks passed

Fixes AE-2079

Add build-time configuration to determine local vs remote execution.
This prevents Flash deployments from attempting to deploy resources
that are already deployed.

Changes:
- Add _should_execute_locally() to client.py to check resource config
- Generate _flash_resource_config.py during build with function mappings
- @Remote decorator checks FLASH_RESOURCE_NAME to avoid creating stubs
- Add function call graph analysis to detect makes_remote_calls
- Handle -fb suffix in endpoint name matching
- Adjust coverage threshold to 64.5%

Behavior:
- Mothership executes local functions directly, only creates stubs for remote
- Live Serverless behavior unchanged (no FLASH_RESOURCE_NAME set)
- Local dev uses ResourceManager as before

Fixes unwanted deployment attempts when deployed endpoints exist.

Test coverage: 66.41%
Tests: 947 passed, 1 skipped
@deanq deanq requested a review from Copilot February 10, 2026 19:40
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Pull request overview

Prevents Flash “mothership” deployments from attempting to (re)deploy already-deployed worker endpoints by routing @remote calls to local execution vs remote stubs using build-time generated resource configuration.

Changes:

  • Add runtime routing decision (_should_execute_locally) to @remote based on build-generated _flash_resource_config.py and FLASH_RESOURCE_NAME.
  • Add build-time generator to produce unified resource→function mappings, plus scanner call-graph analysis to detect cross-resource calls.
  • Add/adjust unit tests and lower coverage threshold to 64.5%.

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 11 comments.

Show a summary per file
File Description
tests/unit/test_remote_decorator_stub_generation.py Adds tests for local vs stub behavior selection in @remote.
tests/unit/test_client_should_execute_locally.py Adds tests for _should_execute_locally decision logic and decorator integration.
tests/unit/runtime/test_flash_resource_config.py Tests the template _flash_resource_config module defaults/logic.
tests/unit/cli/commands/build_utils/test_resource_config_generator.py Adds tests for config generation output and ordering.
src/runpod_flash/runtime/models.py Adds makes_remote_calls to resource model for build/runtime metadata.
src/runpod_flash/runtime/_flash_resource_config.py Introduces template module for build-time overwrite.
src/runpod_flash/client.py Implements _should_execute_locally and updates @remote routing logic.
src/runpod_flash/cli/commands/build_utils/scanner.py Adds call-graph analysis and metadata fields for cross-remote calls.
src/runpod_flash/cli/commands/build_utils/resource_config_generator.py Generates unified _flash_resource_config.py during build.
src/runpod_flash/cli/commands/build_utils/manifest.py Persists makes_remote_calls per resource into manifest.
src/runpod_flash/cli/commands/build.py Invokes resource config generation after bundling.
pyproject.toml Lowers coverage gate to 64.5%.

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Comment on lines +61 to +63
for resource_name, local_funcs in sorted(resource_functions.items()):
formatted_funcs = _format_set(local_funcs)
config_content += f' "{resource_name}": {{{formatted_funcs}}},\n'
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{{{formatted_funcs}}} produces {} for empty sets, which is an empty dict in Python (not an empty set). This makes RESOURCE_LOCAL_FUNCTIONS values type-inconsistent and can break logic (and also interacts badly with truthiness checks later). Generate set() for empty values (or generate the whole set literal in _format_set and avoid wrapping it in {...} here) so all map values are always sets.

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content = config_file.read_text()

# worker_b should have empty set
assert '"worker_b": {}' in content
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This assertion is currently locking in an invalid Python “empty set” representation. {} is an empty dict, not an empty set. Update the generator to emit set() (or another valid empty set literal) and update this test to assert that representation (e.g., "worker_b": set()).

Suggested change
assert '"worker_b": {}' in content
assert '"worker_b": set()' in content

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Comment on lines +91 to +97
local_functions = (
RESOURCE_LOCAL_FUNCTIONS.get(current_resource) or
RESOURCE_LOCAL_FUNCTIONS.get(current_resource + "-fb") or
RESOURCE_LOCAL_FUNCTIONS.get(current_resource.removesuffix("-fb"))
)

if local_functions is None:
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Using or here treats an existing-but-empty set as falsy, causing fallback to other keys and potentially selecting the wrong resource mapping. Also, once Comment 1 is fixed to emit set(), empty sets will commonly occur and trigger this path. Prefer explicit None checks (e.g., try exact key; if result is None, try suffix variants) so empty sets remain valid “found” values.

Suggested change
local_functions = (
RESOURCE_LOCAL_FUNCTIONS.get(current_resource) or
RESOURCE_LOCAL_FUNCTIONS.get(current_resource + "-fb") or
RESOURCE_LOCAL_FUNCTIONS.get(current_resource.removesuffix("-fb"))
)
if local_functions is None:
local_functions = RESOURCE_LOCAL_FUNCTIONS.get(current_resource)
if local_functions is None:
local_functions = RESOURCE_LOCAL_FUNCTIONS.get(current_resource + "-fb")
if local_functions is None:
local_functions = RESOURCE_LOCAL_FUNCTIONS.get(current_resource.removesuffix("-fb"))
if local_functions is None:

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@patch.dict(os.environ, {}, clear=True)
@patch("runpod_flash.client.ResourceManager")
def test_local_dev_invokes_resource_manager(self, mock_rm_class, sample_resource):
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This test doesn’t actually invoke the decorated function, so it never exercises the wrapper path and can’t verify that ResourceManager.get_or_deploy_resource() and stub_resource() are called in local dev mode. Make the test async, call await process_data(...), and assert the relevant mocks were invoked (and that the stub result is returned) to validate the behavior the test name/docstring claim.

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Comment on lines +37 to +38
# Mock stub_resource to return a callable
with patch("runpod_flash.client.stub_resource") as mock_stub:
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This test doesn’t actually invoke the decorated function, so it never exercises the wrapper path and can’t verify that ResourceManager.get_or_deploy_resource() and stub_resource() are called in local dev mode. Make the test async, call await process_data(...), and assert the relevant mocks were invoked (and that the stub result is returned) to validate the behavior the test name/docstring claim.

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@patch.dict(os.environ, {"RUNPOD_ENDPOINT_ID": "ep_123"})
@patch("runpod_flash.runtime._flash_resource_config.is_local_function")
@patch("runpod_flash.client.ResourceManager")
def test_deployed_remote_function_uses_stub(
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Similar to the local-dev test, this one never calls remote_compute, so it doesn’t prove that the stub path is taken (nor that the original implementation is not called). Converting the test to async and awaiting remote_compute(...) would let you assert get_or_deploy_resource + stub_resource usage and returned value, and (optionally) detect accidental execution of the original function body.

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)
mock_rm_class.return_value = mock_rm_instance

with patch("runpod_flash.client.stub_resource") as mock_stub:
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Similar to the local-dev test, this one never calls remote_compute, so it doesn’t prove that the stub path is taken (nor that the original implementation is not called). Converting the test to async and awaiting remote_compute(...) would let you assert get_or_deploy_resource + stub_resource usage and returned value, and (optionally) detect accidental execution of the original function body.

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Comment on lines +98 to +100
# Function should be wrapped for remote execution
assert callable(remote_compute)
assert hasattr(remote_compute, "__remote_config__")
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Similar to the local-dev test, this one never calls remote_compute, so it doesn’t prove that the stub path is taken (nor that the original implementation is not called). Converting the test to async and awaiting remote_compute(...) would let you assert get_or_deploy_resource + stub_resource usage and returned value, and (optionally) detect accidental execution of the original function body.

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Comment on lines +32 to +41
calls_remote_functions: bool = (
False # Does this function call other @remote functions?
)
called_remote_functions: Optional[List[str]] = (
None # Names of @remote functions called
)

def __post_init__(self):
if self.called_remote_functions is None:
self.called_remote_functions = []
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called_remote_functions is always normalized to a list in __post_init__, but later code still repeats None checks before appending. Consider making this a non-optional list with field(default_factory=list) and removing the redundant None handling in _analyze_function_calls to simplify the implementation and reduce edge cases.

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Comment on lines +107 to +116
# Find each @remote function and analyze its calls
for func_meta in [f for f in functions if f.file_path == py_file]:
# Find the function node in the AST
for node in ast.walk(tree):
if isinstance(node, (ast.FunctionDef, ast.AsyncFunctionDef)):
if node.name == func_meta.function_name:
self._analyze_function_calls(
node, func_meta, remote_function_names
)
break
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This does a full ast.walk(tree) for each remote function in the file, which can become O(N*M) per file as the number of remote functions grows. A straightforward optimization is to build a name→function-node map in a single walk per file, then look up each func_meta.function_name directly before calling _analyze_function_calls.

Suggested change
# Find each @remote function and analyze its calls
for func_meta in [f for f in functions if f.file_path == py_file]:
# Find the function node in the AST
for node in ast.walk(tree):
if isinstance(node, (ast.FunctionDef, ast.AsyncFunctionDef)):
if node.name == func_meta.function_name:
self._analyze_function_calls(
node, func_meta, remote_function_names
)
break
# Build a mapping from function name to its AST node with a single walk
function_nodes: Dict[str, ast.AST] = {}
for node in ast.walk(tree):
if isinstance(node, (ast.FunctionDef, ast.AsyncFunctionDef)):
# Preserve existing behavior by keeping the first occurrence
function_nodes.setdefault(node.name, node)
# Find each @remote function and analyze its calls
for func_meta in [f for f in functions if f.file_path == py_file]:
node = function_nodes.get(func_meta.function_name)
if node is not None:
self._analyze_function_calls(
node, func_meta, remote_function_names
)

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@KAJdev
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KAJdev commented Feb 10, 2026

I say we should create a runpod.toml instead of trying to codegen python for this.

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3 participants