Add new step type: step.static_file for serving files from disk by Copilot · Pull Request #250 · GoCodeAlone/workflow

Copilot · 2026-03-03T19:22:56Z

Original prompt

This section details on the original issue you should resolve

<issue_title>New step type: step.static_file for serving files from disk</issue_title>
<issue_description>## Use Case

Pipelines sometimes need to serve static files (OpenAPI specs, HTML pages, configuration files) as HTTP responses. Currently step.raw_response only supports inline body strings or body_from pipeline context references — it cannot read from a file on disk.

Proposed Solution

A new step.static_file step type:
- name: serve_spec
  type: step.static_file
  config:
    file: ./specs/chimera-api.yaml    # resolved relative to config file
    content_type: "application/yaml"
    cache_control: "public, max-age=3600"  # optional
Features:

Reads file at init time (not per-request) for performance

File path resolved relative to the config file's directory (using config.ResolvePathInConfig)

Content-Type must be specified

Optional Cache-Control header

Returns the file content as the HTTP response body

Alternatively, this could be a file or body_file config option on the existing step.raw_response:
- name: serve_spec
  type: step.raw_response
  config:
    content_type: "application/yaml"
    body_file: ./specs/chimera-api.yaml   # NEW: read body from file
Context

Chimera needs to serve an OpenAPI spec file at /openapi.yaml for Swagger UI consumption. The openapi module can do this but also registers routes that conflict with pipeline triggers (see #247). A step.static_file would allow serving the spec via a simple pipeline without route conflicts.

🤖 Generated with Claude Code</issue_description>

<agent_instructions>This would be a simple alternative to the full static.fileserver module that we have existing, by being able to more simply serve a smaller static file use case</agent_instructions>

Comments on the Issue (you are @copilot in this section)

Fixes New step type: step.static_file for serving files from disk #248

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.

intel352 · 2026-03-03T20:38:01Z

@copilot retry

…disk Co-authored-by: intel352 <77607+intel352@users.noreply.github.com>

Copilot · 2026-03-03T20:52:07Z

@copilot retry

Implemented step.static_file in commit 97951e5.

The new step type:

Reads the file at factory creation time (init, not per-request) for performance
Resolves file path relative to the config file directory via config.ResolvePathInConfig
Requires content_type config
Supports optional cache_control header
Sets _response_handled and Stop: true after writing the HTTP response

Example usage:

- name: serve_spec
  type: step.static_file
  config:
    file: ./specs/chimera-api.yaml
    content_type: "application/yaml"
    cache_control: "public, max-age=3600"

Copilot

Pull request overview

Adds a new built-in pipeline step type, step.static_file, to serve a single file from disk as an HTTP response (with init-time file loading and config-relative path resolution), intended as a lightweight alternative to static.fileserver for simple one-file routes.

Changes:

Implement step.static_file step factory + execution behavior (HTTP-writer mode + no-writer fallback).
Register the new step type across plugin manifests/factories, schema registries, and wfctl type registry.
Add unit tests and update plugin step factory expectations.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
`module/pipeline_step_static_file.go`	Implements the new `step.static_file` step (init-time file read; writes HTTP response or returns body in output when no writer).
`module/pipeline_step_static_file_test.go`	Adds unit tests for serving content, no-writer output mode, and config validation/error cases.
`plugins/pipelinesteps/plugin.go`	Registers `step.static_file` in `StepTypes` and `StepFactories`.
`plugins/pipelinesteps/plugin_test.go`	Updates `expectedSteps` list to include `step.static_file`.
`schema/schema.go`	Adds `step.static_file` to `coreModuleTypes`.
`schema/module_schema.go`	Registers the module schema for `step.static_file` (config fields + description).
`cmd/wfctl/type_registry.go`	Adds `step.static_file` to wfctl known step types/config keys.

Copilot · 2026-03-03T21:04:37Z

module/pipeline_step_static_file_test.go

+func TestStaticFileStep_MissingContentType(t *testing.T) {
+	dir := t.TempDir()
+	filePath := filepath.Join(dir, "data.txt")
+	_ = os.WriteFile(filePath, []byte("hello"), 0o600)


os.WriteFile errors are ignored here. If the write fails, this test may pass/fail for the wrong reason (it will later error on missing content_type rather than setup failure). Please assert the write succeeded (like the other tests in this file).

Suggested change

_ = os.WriteFile(filePath, []byte("hello"), 0o600)

if err := os.WriteFile(filePath, []byte("hello"), 0o600); err != nil {

t.Fatalf("write temp file: %v", err)

}

Copilot · 2026-03-03T21:04:37Z

schema/module_schema.go

+		Category:    "pipeline",
+		Description: "Serves a static file from disk as an HTTP response; file is read at init time for performance",
+		Inputs:      []ServiceIODef{{Name: "context", Type: "PipelineContext", Description: "Pipeline context (HTTP response writer)"}},
+		Outputs:     []ServiceIODef{{Name: "result", Type: "StepResult", Description: "HTTP response with file content"}},


The schema output description is a bit misleading/inconsistent with other response steps: when an HTTP writer is present, the file content is written to the response but is not present in StepResult.Output. Consider wording this like step.json_response (e.g., “writes an HTTP response and stops the pipeline”; optionally mention the no-writer fallback returns body).

Suggested change

Outputs: []ServiceIODef{{Name: "result", Type: "StepResult", Description: "HTTP response with file content"}},

Outputs: []ServiceIODef{{Name: "result", Type: "StepResult", Description: "Writes an HTTP response with file content and stops the pipeline; if no HTTP writer is available, returns the file content in StepResult.Output as body"}},

Copilot · 2026-03-03T21:04:37Z

module/pipeline_step_static_file_test.go

+	factory := NewStaticFileStepFactory()
+	step, err := factory("serve_spec", map[string]any{
+		"file":          filePath,
+		"content_type":  "application/yaml",
+		"cache_control": "public, max-age=3600",
+	}, nil)
+	if err != nil {
+		t.Fatalf("factory error: %v", err)


The tests don’t cover the advertised config-relative path resolution via _config_dir/config.ResolvePathInConfig (i.e., passing a relative file path and setting _config_dir in the step config). Adding a test for this would guard the primary feature this step is introducing.

Copilot · 2026-03-03T21:04:38Z

module/pipeline_step_static_file_test.go

+	resp := recorder.Result()
+	if resp.StatusCode != 200 {
+		t.Errorf("expected status 200, got %d", resp.StatusCode)
+	}
+	if ct := resp.Header.Get("Content-Type"); ct != "application/yaml" {
+		t.Errorf("expected Content-Type application/yaml, got %q", ct)
+	}
+	if cc := resp.Header.Get("Cache-Control"); cc != "public, max-age=3600" {
+		t.Errorf("expected Cache-Control header, got %q", cc)
+	}
+
+	body, _ := io.ReadAll(resp.Body)
+	if string(body) != content {
+		t.Errorf("expected body %q, got %q", content, string(body))


Avoid ignoring I/O errors in tests: io.ReadAll(resp.Body) drops the returned error, and resp.Body isn’t closed. Checking the read error and closing the body will prevent false positives and resource leaks if the response body can’t be read for some reason.

intel352 · 2026-03-03T21:11:53Z

@copilot apply changes based on the comments in this thread

Co-authored-by: intel352 <77607+intel352@users.noreply.github.com>

Copilot · 2026-03-03T21:18:39Z

@copilot apply changes based on the comments in this thread

Applied all 4 review changes in commit c159f2b:

Fixed ignored os.WriteFile error in TestStaticFileStep_MissingContentType
Fixed dropped io.ReadAll error and added resp.Body.Close() in TestStaticFileStep_ServesFile
Added TestStaticFileStep_ConfigRelativePath test covering _config_dir-relative path resolution via config.ResolvePathInConfig
Updated schema output description to accurately describe both HTTP-writer and no-writer behavior

Initial plan

0b1dcf1

Copilot AI assigned Copilot and intel352 Mar 3, 2026

Copilot started work on behalf of intel352 March 3, 2026 19:23 View session

Copilot stopped work on behalf of intel352 due to an error March 3, 2026 19:25
The "Checkout code" custom setup step from your .github/workflows/copilot-setup-steps.yml file failed.

Copilot started work on behalf of intel352 March 3, 2026 20:38 View session

feat: add step.static_file pipeline step type for serving files from …

97951e5

…disk Co-authored-by: intel352 <77607+intel352@users.noreply.github.com>

Copilot AI changed the title ~~[WIP] Add new step type: step.static_file for serving files from disk~~ Add new step type: step.static_file for serving files from disk Mar 3, 2026

Copilot finished work on behalf of intel352 March 3, 2026 20:52

Merge branch 'main' into copilot/add-static-file-step-type

080c9f6

intel352 marked this pull request as ready for review March 3, 2026 21:00

Copilot AI review requested due to automatic review settings March 3, 2026 21:00

Copilot started reviewing on behalf of intel352 March 3, 2026 21:01 View session

Copilot AI reviewed Mar 3, 2026

View reviewed changes

Copilot started work on behalf of intel352 March 3, 2026 21:12 View session

fix: address PR review comments on step.static_file tests and schema

c159f2b

Co-authored-by: intel352 <77607+intel352@users.noreply.github.com>

Copilot finished work on behalf of intel352 March 3, 2026 21:20

Merge branch 'main' into copilot/add-static-file-step-type

c9bc3cf

intel352 merged commit ef8b897 into main Mar 3, 2026
14 checks passed

intel352 deleted the copilot/add-static-file-step-type branch March 3, 2026 22:41

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Add new step type: step.static_file for serving files from disk#250

Add new step type: step.static_file for serving files from disk#250
intel352 merged 5 commits intomainfrom
copilot/add-static-file-step-type

Copilot AI commented Mar 3, 2026 •

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-	_ = os.WriteFile(filePath, []byte("hello"), 0o600)
+	if err := os.WriteFile(filePath, []byte("hello"), 0o600); err != nil {
+		t.Fatalf("write temp file: %v", err)
+	}

	Outputs: []ServiceIODef{{Name: "result", Type: "StepResult", Description: "HTTP response with file content"}},
	Outputs: []ServiceIODef{{Name: "result", Type: "StepResult", Description: "Writes an HTTP response with file content and stops the pipeline; if no HTTP writer is available, returns the file content in StepResult.Output as body"}},

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Proposed Solution

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Copilot AI commented Mar 3, 2026 •

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