run build from root for monorepos

Author: blidd-google

packages/@apphosting/adapter-nextjs/src/bin/build.ts

@@ -16,13 +16,19 @@ if (process.env.FIREBASE_APP_DIRECTORY) {
   projectRoot = projectRoot.concat("/", process.env.FIREBASE_APP_DIRECTORY);
 }
 
-// Determine which build runner to use
-let cmd = DEFAULT_COMMAND;
-if (process.env.MONOREPO_COMMAND) {
-  cmd = process.env.MONOREPO_COMMAND;
+// Determine which command to run the build
+const cmd = process.env.MONOREPO_COMMAND || DEFAULT_COMMAND;
+
+// Parse args to pass to the build command
+let cmdArgs: string[] = [];
+if (process.env.MONOREPO_BUILD_ARGS) {
+  cmdArgs = process.env.MONOREPO_BUILD_ARGS.split(",");
 }
 
-build(projectRoot, cmd);
+// Run build command from the subdirectory if specified.
+// N.B. We run the build command from the root for monorepo builds, so that the build process can
+// locate necessary files outside the project directory.
+build(process.env.MONOREPO_CMD ? root : projectRoot, cmd, ...cmdArgs);
 
 const outputBundleOptions = populateOutputBundleOptions(root, projectRoot);
 const { distDir } = await loadConfig(root, projectRoot);

packages/@apphosting/adapter-nextjs/src/utils.ts

@@ -70,12 +70,12 @@ export function populateOutputBundleOptions(rootDir: string, appDir: string): Ou
 }
 
 // Run build command
-export function build(cwd: string, cmd = DEFAULT_COMMAND): void {
+export function build(cwd: string, cmd = DEFAULT_COMMAND, ...argv: string[]): void {
   // Set standalone mode
   process.env.NEXT_PRIVATE_STANDALONE = "true";
   // Opt-out sending telemetry to Vercel
   process.env.NEXT_TELEMETRY_DISABLED = "1";
-  spawnSync(cmd, ["run", "build"], { cwd, shell: true, stdio: "inherit" });
+  spawnSync(cmd, ["run", "build", ...argv], { cwd, shell: true, stdio: "inherit" });
 }
 
 /**