cmd/build: expose new configurable via --prune-unused

Signed-off-by: Stephan Renatus <stephan.renatus@gmail.com>

cmd/build.go

@@ -27,6 +27,7 @@ type buildParams struct {
 	capabilities       *capabilitiesFlag
 	target             *util.EnumFlag
 	bundleMode         bool
+	pruneUnused        bool
 	optimizationLevel  int
 	entrypoints        repeatedStringFlag
 	outputFile         string
@@ -114,6 +115,11 @@ The 'build' command supports targets (specified by -t):
             the input files for each specified entrypoint. The bundle may contain the
             original policy or data files.
 
+    plan    The plan target emits a bundle containing a plan, i.e., an intermediate
+			representation compiled from the input files for each specified entrypoint.
+			This is for further processing, OPA cannot evaluate a "plan bundle" like it
+			can evaluate a wasm or rego bundle.
+
 The -e flag tells the 'build' command which documents will be queried by the software
 asking for policy decisions, so that it can focus optimization efforts and ensure
 that document is not eliminated by the optimizer.
@@ -218,7 +224,8 @@ against OPA v0.22.0:
 	}
 
 	buildCommand.Flags().VarP(buildParams.target, "target", "t", "set the output bundle target type")
-	buildCommand.Flags().BoolVarP(&buildParams.debug, "debug", "", false, "enable debug output")
+	buildCommand.Flags().BoolVar(&buildParams.pruneUnused, "prune-unused", false, "exclude dependents of entrypoints")
+	buildCommand.Flags().BoolVar(&buildParams.debug, "debug", false, "enable debug output")
 	buildCommand.Flags().IntVarP(&buildParams.optimizationLevel, "optimize", "O", 0, "set optimization level")
 	buildCommand.Flags().VarP(&buildParams.entrypoints, "entrypoint", "e", "set slash separated entrypoint path")
 	buildCommand.Flags().VarP(&buildParams.revision, "revision", "r", "set output bundle revision")
@@ -273,6 +280,7 @@ func dobuild(params buildParams, args []string) error {
 		WithCapabilities(capabilities).
 		WithTarget(params.target.String()).
 		WithAsBundle(params.bundleMode).
+		WithPruneUnused(params.pruneUnused).
 		WithOptimizationLevel(params.optimizationLevel).
 		WithOutput(buf).
 		WithEntrypoints(params.entrypoints.v...).

cmd/build_test.go

@@ -220,3 +220,71 @@ func TestBuildVerificationConfigError(t *testing.T) {
 		}
 	})
 }
+
+func TestBuildPlanWithPruneUnused(t *testing.T) {
+
+	files := map[string]string{
+		"test.rego": `
+			package test
+			
+			p[1]
+			
+			f(x) { p[x] }
+		`,
+	}
+
+	test.WithTempFS(files, func(root string) {
+		params := newBuildParams()
+		if err := params.target.Set("plan"); err != nil {
+			t.Fatal(err)
+		}
+		params.pruneUnused = true
+		params.entrypoints.v = []string{"test"}
+		params.outputFile = path.Join(root, "bundle.tar.gz")
+
+		err := dobuild(params, []string{root})
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		_, err = loader.NewFileLoader().AsBundle(params.outputFile)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		// Check that manifest is not written given no input manifest and no other flags
+		f, err := os.Open(params.outputFile)
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer f.Close()
+
+		gr, err := gzip.NewReader(f)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		tr := tar.NewReader(gr)
+
+		found := false // for plan.json
+
+		for {
+			f, err := tr.Next()
+			if err == io.EOF {
+				break
+			} else if err != nil {
+				t.Fatal(err)
+			}
+			switch {
+			case f.Name == "/plan.json":
+				found = true
+			case f.Name == "/data.json" || strings.HasSuffix(f.Name, "/test.rego"): // expected
+			default:
+				t.Errorf("unexpected file: %s", f.Name)
+			}
+		}
+		if !found {
+			t.Error("plan.json not found")
+		}
+	})
+}