feat: add --target flag for target-specific visualization#810
Merged
patrickhoefler merged 5 commits intomainfrom Mar 13, 2026
Merged
feat: add --target flag for target-specific visualization#810patrickhoefler merged 5 commits intomainfrom
patrickhoefler merged 5 commits intomainfrom
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Adds a --target flag that limits the graph to stages transitively needed to build the specified targets, eliding everything else. Also includes three refactorings that fit naturally with this change: - Introduce ParseOptions and BuildOptions structs to replace the growing positional parameter lists on LoadAndParseDockerfile and BuildDotFile - Move ScratchModeFromString into the dockerfile2dot package next to the ScratchMode type it converts to - Extract a shared findStageIndex helper to eliminate duplicate stage lookup logic between convert.go and build.go Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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Pull request overview
Adds target-scoped graph generation so users can visualize only the stages needed to build one or more specified targets, instead of always rendering the full multi-stage Dockerfile graph.
Changes:
- Introduces
--targetCLI flag and target filtering in the Dockerfile parsing pipeline. - Refactors parsing/rendering APIs to use
ParseOptions/BuildOptionsstructs instead of long parameter lists. - Consolidates stage lookup logic via
findStageIndexand relocatesScratchModeFromStringintodockerfile2dot.
Reviewed changes
Copilot reviewed 12 out of 12 changed files in this pull request and generated 3 comments.
Show a summary per file
| File | Description |
|---|---|
| internal/dockerfile2dot/structs.go | Adds option structs + shared helpers (findStageIndex, ScratchModeFromString). |
| internal/dockerfile2dot/load.go | Threads ParseOptions through parsing and applies filterToTargets when Targets are set. |
| internal/dockerfile2dot/load_test.go | Updates tests to call LoadAndParseDockerfile with ParseOptions. |
| internal/dockerfile2dot/filter.go | Implements reachability-based stage filtering + numeric WaitFor remapping + external image filtering. |
| internal/dockerfile2dot/filter_test.go | Adds focused unit tests for target filtering behavior and remapping. |
| internal/dockerfile2dot/convert.go | Updates converter to accept ParseOptions; refactors external-image resolution to use shared stage lookup. |
| internal/dockerfile2dot/convert_test.go | Adds tests for ScratchModeFromString and findStageIndex; updates converter tests for ParseOptions. |
| internal/dockerfile2dot/build.go | Updates DOT builder to accept BuildOptions; refactors stage node ID resolution using findStageIndex. |
| internal/dockerfile2dot/build_test.go | Updates tests to call BuildDotFile with BuildOptions. |
| internal/cmd/root.go | Adds --target flag wiring; switches to ParseOptions/BuildOptions and package-level ScratchModeFromString. |
| internal/cmd/root_test.go | Updates help output and adds CLI integration coverage for --target. |
| README.md | Documents the new --target flag in examples and the full flags list. |
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… from external image filter Two correctness fixes from code review: - Trim whitespace from --target values so "--target a, b" works (consistent with how --separate normalizes its inputs) - In filterExternalImages, skip WaitFor IDs that resolve to an internal stage so a kept stage named "alpine" doesn't incorrectly retain an unrelated external image with the same ID from an elided stage Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
The comment claimed -1 is returned for out-of-range numeric indices, but the implementation returns the parsed index value. Update the comment to accurately describe both the numeric out-of-range and name-not-found cases. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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Pull request overview
Adds a --target CLI flag to visualize only the stages transitively required to build selected Dockerfile targets, aligning the graph output with target-focused workflows (issue #686). This is supported by internal parsing/build API refactors and shared helpers.
Changes:
- Add
--targetflag and stage filtering logic (filterToTargets) to elide unrelated stages and external images. - Refactor dockerfile2dot entrypoints to use
ParseOptions/BuildOptionsstructs instead of long positional parameter lists. - Consolidate shared helpers (
findStageIndex,ScratchModeFromString, stage node ID building) to reduce duplicated stage lookup logic.
Reviewed changes
Copilot reviewed 12 out of 12 changed files in this pull request and generated 2 comments.
Show a summary per file
| File | Description |
|---|---|
| internal/dockerfile2dot/structs.go | Adds shared helpers and introduces ParseOptions/BuildOptions. |
| internal/dockerfile2dot/load.go | Plumbs ParseOptions through parsing and applies optional target filtering. |
| internal/dockerfile2dot/load_test.go | Updates tests for the new ParseOptions API. |
| internal/dockerfile2dot/filter.go | Implements filtering to requested targets, including index remapping and external image pruning. |
| internal/dockerfile2dot/filter_test.go | Adds comprehensive unit tests for target filtering behavior and edge cases. |
| internal/dockerfile2dot/convert.go | Updates parsing pipeline to accept ParseOptions and uses shared stage lookup for dependency handling. |
| internal/dockerfile2dot/convert_test.go | Adds tests for ScratchModeFromString and findStageIndex; updates parse tests for ParseOptions. |
| internal/dockerfile2dot/build.go | Updates build API to BuildOptions and refactors stage node ID resolution. |
| internal/dockerfile2dot/build_test.go | Updates tests for the new BuildOptions API. |
| internal/cmd/root.go | Wires --target into CLI and passes options structs to dockerfile2dot APIs. |
| internal/cmd/root_test.go | Updates CLI usage text and adds end-to-end tests covering --target behavior. |
| README.md | Documents the new --target flag and updates the flags list. |
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- resolveTargetIndices now returns an error when all target entries are
empty or whitespace-only, preventing a silent empty graph
- Fix grammar in ScratchModeFromString doc comment ("returns" → "return")
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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Pull request overview
Adds target-specific Dockerfile graph rendering so users can visualize only the stages required to build one or more selected targets, aligning with #686.
Changes:
- Add
--targetCLI flag and implement stage graph filtering to only keep stages transitively required by the specified targets. - Refactor
dockerfile2dotAPIs to useParseOptions/BuildOptionsstructs and centralize helper logic (ScratchModeFromString,findStageIndex). - Add comprehensive unit/integration tests for target filtering behavior and the new helpers.
Reviewed changes
Copilot reviewed 12 out of 12 changed files in this pull request and generated 4 comments.
Show a summary per file
| File | Description |
|---|---|
| internal/dockerfile2dot/structs.go | Adds ParseOptions/BuildOptions, findStageIndex, and ScratchModeFromString. |
| internal/dockerfile2dot/load.go | Plumbs ParseOptions and applies filterToTargets when targets are provided. |
| internal/dockerfile2dot/filter.go | Implements target reachability filtering + WaitFor ID remapping + external image pruning. |
| internal/dockerfile2dot/convert.go | Refactors parsing to take ParseOptions; updates external image resolution logic. |
| internal/dockerfile2dot/build.go | Refactors rendering to take BuildOptions; deduplicates stage lookup via findStageIndex. |
| internal/dockerfile2dot/load_test.go | Updates tests to call LoadAndParseDockerfile with ParseOptions. |
| internal/dockerfile2dot/convert_test.go | Adds tests for ScratchModeFromString and findStageIndex; updates parse tests for ParseOptions. |
| internal/dockerfile2dot/build_test.go | Updates tests to call BuildDotFile with BuildOptions. |
| internal/dockerfile2dot/filter_test.go | Adds unit tests covering target filtering, remapping, and external image pruning. |
| internal/cmd/root.go | Adds --target flag; plumbs new options structs into dockerfile2dot calls. |
| internal/cmd/root_test.go | Extends CLI tests to validate --target output and error behavior. |
| README.md | Documents the new --target flag in usage + options list. |
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Add a NOTE comment explaining that findStageIndex searches all stages regardless of definition order, which differs from Docker's behavior of only allowing references to previously-defined stages. This is a pre-existing limitation affecting multiple call sites across the codebase, not introduced by the --target feature. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Adds a --target flag that limits the graph to stages transitively needed to build the specified targets, eliding everything else.
Also includes three refactorings that fit naturally with this change:
Closes #686