feat(cli): copy python-executor into gateway-runtime image

Gateway-builder now emits a python-executor/ directory alongside the
gateway-runtime build context. Stage it into the runtime context and
add a COPY step in the runtime Dockerfile template so the custom
python-executor replaces the one baked into the base image, matching
the existing policy-engine binary pattern.

Author: renuka-fernando

cli/src/internal/gateway/docker_build.go

@@ -74,6 +74,10 @@ func BuildGatewayImages(config DockerBuildConfig) error {
 		return err
 	}
 
+	if err := ensurePythonExecutorInRuntimeContext(config.TempDir); err != nil {
+		return err
+	}
+
 	fmt.Println("  ✓ Gateway-builder completed")
 
 	// Step 2: Build the two images
@@ -121,6 +125,30 @@ func ensureBuildLockInControllerContext(tempDir string) error {
 	return nil
 }
 
+// ensurePythonExecutorInRuntimeContext stages the python-executor directory
+// produced by gateway-builder into the gateway-runtime Docker build context
+// so the Dockerfile's `COPY python-executor/ ...` can resolve it.
+func ensurePythonExecutorInRuntimeContext(tempDir string) error {
+	pythonExecutorSrc := filepath.Join(tempDir, "output", "python-executor")
+	if _, err := os.Stat(pythonExecutorSrc); err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			return nil
+		}
+		return fmt.Errorf("failed to access python-executor output: %w", err)
+	}
+
+	pythonExecutorDst := filepath.Join(tempDir, "output", "gateway-runtime", "python-executor")
+	if err := os.RemoveAll(pythonExecutorDst); err != nil {
+		return fmt.Errorf("failed to clear existing python-executor in gateway-runtime build context: %w", err)
+	}
+
+	if err := utils.CopyDir(pythonExecutorSrc, pythonExecutorDst); err != nil {
+		return fmt.Errorf("failed to copy python-executor into gateway-runtime build context: %w", err)
+	}
+
+	return nil
+}
+
 // runGatewayBuilder runs the gateway-builder container
 func runGatewayBuilder(config DockerBuildConfig, logFile *os.File) error {
 	args := []string{"run", "--rm", "-v", config.TempDir + ":/workspace", config.GatewayBuilder,

gateway/gateway-builder/templates/Dockerfile.gateway-runtime.tmpl

@@ -24,6 +24,10 @@ USER root
 COPY policy-engine /app/policy-engine
 RUN chmod +x /app/policy-engine
 
+# Replace python-executor with custom-compiled version containing user Python policies
+RUN rm -rf /app/python-executor
+COPY python-executor/ /app/python-executor/
+
 USER wso2
 
 # Metadata labels