dockerfile: expose TARGETSTAGE as builtin argument

Allows capturing what build stage is currently being built for patterns with better base stage reuse. Signed-off-by: Tonis Tiigi <[email protected]>
moby · Oct 19, 2024 · 6a31a78 · 6a31a78
1 parent f835dd4
commit 6a31a78
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Showing 3 changed files with 128 additions and 5 deletions.
diff --git a/frontend/dockerfile/dockerfile2llb/convert.go b/frontend/dockerfile/dockerfile2llb/convert.go
@@ -227,10 +227,6 @@ func toDispatchState(ctx context.Context, dt []byte, opt ConvertOpt) (*dispatchS
  opt.LLBCaps = &caps
  }
 
- platformOpt := buildPlatformOpt(&opt)
-
- globalArgs := platformArgs(platformOpt, opt.BuildArgs)
-
  dockerfile, err := parser.Parse(bytes.NewReader(dt))
  if err != nil {
  return nil, err
@@ -261,6 +257,13 @@ func toDispatchState(ctx context.Context, dt []byte, opt ConvertOpt) (*dispatchS
  validateStageNames(stages, lint)
  validateCommandCasing(stages, lint)
 
+ platformOpt := buildPlatformOpt(&opt)
+ targetName := opt.Target
+ if targetName == "" {
+ targetName = stages[len(stages)-1].Name
+ }
+ globalArgs := defaultArgs(platformOpt, opt.BuildArgs, targetName)
+
  shlex := shell.NewLex(dockerfile.EscapeToken)
  outline := newOutlineCapture()
 

diff --git a/frontend/dockerfile/dockerfile2llb/platform.go b/frontend/dockerfile/dockerfile2llb/platform.go
@@ -36,9 +36,12 @@ func buildPlatformOpt(opt *ConvertOpt) *platformOpt {
  }
 }
 
-func platformArgs(po *platformOpt, overrides map[string]string) *llb.EnvList {
+func defaultArgs(po *platformOpt, overrides map[string]string, target string) *llb.EnvList {
  bp := po.buildPlatforms[0]
  tp := po.targetPlatform
+ if target == "" {
+ target = "default"
+ }
  s := [...][2]string{
  {"BUILDPLATFORM", platforms.Format(bp)},
  {"BUILDOS", bp.OS},
@@ -48,6 +51,7 @@ func platformArgs(po *platformOpt, overrides map[string]string) *llb.EnvList {
  {"TARGETOS", tp.OS},
  {"TARGETARCH", tp.Architecture},
  {"TARGETVARIANT", tp.Variant},
+ {"TARGETSTAGE", target},
  }
  env := &llb.EnvList{}
  for _, kv := range s {

diff --git a/frontend/dockerfile/dockerfile_test.go b/frontend/dockerfile/dockerfile_test.go
@@ -207,6 +207,7 @@ var allTests = integration.TestFuncs(
  testHistoryFinalizeTrace,
  testEmptyStages,
  testLocalCustomSessionID,
+ testTargetStageNameArg,
 )
 
 // Tests that depend on the `security.*` entitlements
@@ -1791,6 +1792,121 @@ COPY Dockerfile .
  }
 }
 
+func testTargetStageNameArg(t *testing.T, sb integration.Sandbox) {
+ integration.SkipOnPlatform(t, "windows")
+ f := getFrontend(t, sb)
+
+ dockerfile := []byte(`
+FROM alpine AS base
+WORKDIR /out
+RUN echo -n "value:$TARGETSTAGE" > /out/first
+ARG TARGETSTAGE
+RUN echo -n "value:$TARGETSTAGE" > /out/second
+
+FROM scratch AS foo
+COPY --from=base /out/ /
+
+FROM scratch
+COPY --from=base /out/ /
+`)
+
+ dir := integration.Tmpdir(
+ t,
+ fstest.CreateFile("Dockerfile", dockerfile, 0600),
+ )
+
+ destDir := t.TempDir()
+
+ c, err := client.New(sb.Context(), sb.Address())
+ require.NoError(t, err)
+ defer c.Close()
+
+ _, err = f.Solve(sb.Context(), c, client.SolveOpt{
+ LocalMounts: map[string]fsutil.FS{
+ dockerui.DefaultLocalNameDockerfile: dir,
+ dockerui.DefaultLocalNameContext: dir,
+ },
+ FrontendAttrs: map[string]string{
+ "target": "foo",
+ },
+ Exports: []client.ExportEntry{
+ {
+ Type: client.ExporterLocal,
+ OutputDir: destDir,
+ },
+ },
+ }, nil)
+ require.NoError(t, err)
+
+ dt, err := os.ReadFile(filepath.Join(destDir, "first"))
+ require.NoError(t, err)
+ require.Equal(t, "value:", string(dt))
+
+ dt, err = os.ReadFile(filepath.Join(destDir, "second"))
+ require.NoError(t, err)
+ require.Equal(t, "value:foo", string(dt))
+
+ destDir = t.TempDir()
+
+ _, err = f.Solve(sb.Context(), c, client.SolveOpt{
+ LocalMounts: map[string]fsutil.FS{
+ dockerui.DefaultLocalNameDockerfile: dir,
+ dockerui.DefaultLocalNameContext: dir,
+ },
+ Exports: []client.ExportEntry{
+ {
+ Type: client.ExporterLocal,
+ OutputDir: destDir,
+ },
+ },
+ }, nil)
+ require.NoError(t, err)
+
+ dt, err = os.ReadFile(filepath.Join(destDir, "first"))
+ require.NoError(t, err)
+ require.Equal(t, "value:", string(dt))
+
+ dt, err = os.ReadFile(filepath.Join(destDir, "second"))
+ require.NoError(t, err)
+ require.Equal(t, "value:default", string(dt))
+
+ // stage name defined in Dockerfile but not passed in request
+ dockerfile = append(dockerfile, []byte(`
+ 
+ FROM scratch AS final
+ COPY --from=base /out/ /
+ `)...)
+
+ dir = integration.Tmpdir(
+ t,
+ fstest.CreateFile("Dockerfile", dockerfile, 0600),
+ )
+
+ destDir = t.TempDir()
+
+ _, err = f.Solve(sb.Context(), c, client.SolveOpt{
+ LocalMounts: map[string]fsutil.FS{
+ dockerui.DefaultLocalNameDockerfile: dir,
+ dockerui.DefaultLocalNameContext: dir,
+ },
+ Exports: []client.ExportEntry{
+ {
+ Type: client.ExporterLocal,
+ OutputDir: destDir,
+ },
+ },
+ }, nil)
+ require.NoError(t, err)
+
+ dt, err = os.ReadFile(filepath.Join(destDir, "first"))
+ require.NoError(t, err)
+ require.Equal(t, "value:", string(dt))
+
+ dt, err = os.ReadFile(filepath.Join(destDir, "second"))
+ require.NoError(t, err)
+ require.Equal(t, "value:final", string(dt))
+}
+
 func testExportMultiPlatform(t *testing.T, sb integration.Sandbox) {
  integration.SkipOnPlatform(t, "windows")
  workers.CheckFeatureCompat(t, sb, workers.FeatureOCIExporter, workers.FeatureMultiPlatform)