json output for schema

Signed-off-by: Kartikay <kartikay_2101ce32@iitp.ac.in>

Author: kartikaysaxena

internal/cmd/preview.go

@@ -11,4 +11,4 @@ func registerPreviewCmd(rootCmd *cobra.Command) {
 	}
 
 	rootCmd.AddCommand(previewCmd)
-}
+}

internal/cmd/schema.go

@@ -2,6 +2,7 @@ package cmd
 
 import (
 	"context"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"io"
@@ -105,6 +106,7 @@ func registerAdditionalSchemaCmds(schemaCmd *cobra.Command) {
 
 	schemaCmd.AddCommand(schemaCompileCmd)
 	schemaCompileCmd.Flags().String("out", "", "output filepath; omitting writes to stdout")
+	schemaCompileCmd.Flags().Bool("json", false, "output schema as JSON")
 }
 
 func schemaDiffCmdFunc(_ *cobra.Command, args []string) error {
@@ -392,6 +394,7 @@ func determinePrefixForSchema(ctx context.Context, specifiedPrefix string, clien
 
 func schemaCompileOuter(cmd *cobra.Command, args []string) (bool, error) {
 	outputFilepath := cobrautil.MustGetString(cmd, "out")
+	asJson := cobrautil.MustGetBool(cmd, "json")
 
 	var outputFile *os.File
 	var toStdout bool
@@ -413,12 +416,12 @@ func schemaCompileOuter(cmd *cobra.Command, args []string) (bool, error) {
 		}()
 	}
 
-	return toStdout, schemaCompileInner(cmd.Context(), args, outputFile)
+	return toStdout, schemaCompileInner(cmd.Context(), args, asJson, outputFile)
 }
 
 // Compiles an input schema written in the new composable schema syntax
 // and produces it as a fully-realized schema
-func schemaCompileInner(ctx context.Context, args []string, writer io.Writer) error {
+func schemaCompileInner(ctx context.Context, args []string, asJson bool, writer io.Writer) error {
 	inputFilepath := args[0]
 	inputSourceFolder := filepath.Dir(inputFilepath)
 	schemaBytes, err := os.ReadFile(inputFilepath)
@@ -449,6 +452,21 @@ func schemaCompileInner(ctx context.Context, args []string, writer io.Writer) er
 	// Add a newline at the end for hygiene's sake
 	terminated := generated + "\n"
 
+	if asJson {
+		output := struct {
+			SchemaText string `json:"schemaText"`
+		}{
+			SchemaText: terminated,
+		}
+
+		jsonOutput, err := json.Marshal(output)
+		if err != nil {
+			return err
+		}
+
+		terminated = string(jsonOutput)
+	}
+
 	_, err = fmt.Fprint(writer, terminated)
 	if err != nil {
 		return fmt.Errorf("failed to write schema: %w", err)

internal/cmd/schema_test.go

@@ -201,7 +201,7 @@ definition resource {
 	var buf []byte
 	writer := &testWriter{buffer: &buf}
 
-	err := schemaCompileInner(t.Context(), files, writer)
+	err := schemaCompileInner(t.Context(), files, false, writer)
 
 	require.NoError(err)
 	require.Equal(expected, string(buf))
@@ -213,7 +213,7 @@ func TestSchemaCompileFileNotFound(t *testing.T) {
 
 	files := []string{filepath.Join("preview-test", "nonexistent.zed")}
 
-	err := schemaCompileInner(t.Context(), files, io.Discard)
+	err := schemaCompileInner(t.Context(), files, false, io.Discard)
 	require.Error(err)
 	require.ErrorIs(err, fs.ErrNotExist)
 }
@@ -225,7 +225,7 @@ func TestSchemaCompileFailureFromReservedKeyword(t *testing.T) {
 	files := []string{filepath.Join("preview-test", "composable-schema-invalid-root.zed")}
 	var expectedErr compiler.BaseCompilerError
 
-	err := schemaCompileInner(t.Context(), files, io.Discard)
+	err := schemaCompileInner(t.Context(), files, false, io.Discard)
 	require.Error(err)
 	require.ErrorAs(err, &expectedErr)
 }
@@ -236,7 +236,7 @@ func TestSchemaCompileWriteError(t *testing.T) {
 
 	files := []string{filepath.Join("preview-test", "composable-schema-root.zed")}
 
-	err := schemaCompileInner(t.Context(), files, &failingWriter{err: errors.New("simulated write failure")})
+	err := schemaCompileInner(t.Context(), files,false,  &failingWriter{err: errors.New("simulated write failure")})
 
 	require.Error(err)
 	require.ErrorContains(err, "failed to write schema")
@@ -253,7 +253,7 @@ func TestSchemaCompileEmptySchema(t *testing.T) {
 
 	files := []string{emptySchemaFile}
 
-	err = schemaCompileInner(t.Context(), files, io.Discard)
+	err = schemaCompileInner(t.Context(), files, false, io.Discard)
 
 	require.Error(err)
 	require.ErrorContains(err, "attempted to compile empty schema")