feat: add --ci flag to grow install

grow/commands/subcommands/install.py

@@ -22,7 +22,10 @@
                    'known Gerrit host amongst the remotes in your repository.')
 @click.option('--force', '-f', default=False, is_flag=True,
              help='Whether to force install even when no changes found.')
-def install(pod_path, gerrit, force):
+@click.option('--ci/--no-ci', default=False,
+              help='Whether to use the `npm ci` command instead of the '
+                   '`npm install` command.')
+def install(pod_path, gerrit, force, ci):
     """Checks whether the pod depends on npm, bower, and gulp and installs them
     if necessary. Then, runs install commands. Also optionally installs the
     Gerrit Code Review commit hook."""
@@ -33,6 +36,7 @@ def install(pod_path, gerrit, force):
         config = base_config.BaseConfig()
         config.set('gerrit', gerrit)
         config.set('force', force)
+        config.set('ci', ci)
         built_in_installers = []
         for installer_class in installers.BUILT_IN_INSTALLERS:
             built_in_installers.append(installer_class(pod, config))

grow/sdk/installers/npm_installer.py

@@ -97,14 +97,16 @@ def _generate_hashes(self):
 
     def _install_npm(self):
         """Install dependencies using npm."""
-        install_command = self._nvm_command('npm install')
+        command = 'npm install' if not self.config.get('ci') else 'npm ci'
+        install_command = self._nvm_command(command)
+        self.pod.logger.info('Running: {}'.format(install_command))
         process = subprocess.Popen(install_command, **self.subprocess_args(shell=True))
         code = process.wait()
         if not code:
             self.pod.write_file(INSTALL_HASH_FILE, self._generate_hashes())
             return
         raise base_installer.InstallError(
-            'There was an error running `npm install`.')
+            'There was an error running `{}`.'.format(command))
 
     def _install_yarn(self):
         """Install dependencies using npm."""