Managing App Engine Applications

Cloud SDK includes the gcloud preview app command for managing App Engine applications. You can use this command to upload new versions of application code, configuration, and static files for your app to App Engine. You can also use the command to manage datastore indexes and download log data.

Table of Contents

1. Installation
2. Running the app locally
3. Deploying an app
4. Listing app versions
5. Deploying datastore indexes
6. Deploying Task Queue configuration
7. Deploying the DoS protection configuration
8. Managing scheduled tasks
9. Downloading source code
10. Downloading logs

Installation

In order to use gcloud preview app , you need to install the app component:

$ gcloud components update app

If you have not already installed the Cloud SDK, follow the installation instructions in the Quick Start guide.

Running the app locally

Once you have authenticated into Google Cloud Platform and created a directory for your app containing app.yaml configuration file, you can run your app in a local development web server.

$ gcloud preview app run DIRECTORY

The web server listens on port 8080 by default. You can visit the application at this URL: http://localhost:8080 .

To change which port the web server uses, use the --host flag:

$ gcloud preview app run --host localhost:9999 DIRECTORY

To stop the web server in Mac OS X or Unix, press Control-C, or Control-Break in your command prompt window if you are running in Windows.

Deploying an app

To deploy application files, run gcloud preview app with the deploy command and the name of your application's root directory. The root directory should contain the app.yaml file for the application.

$ gcloud preview app deploy DIRECTORY

gcloud preview app deploy deploys all application code and modules as well as indexes, cron jobs, denial of service settings, and queues. You can deploy some of the configuration settings of your app separately. For example, to deploy just indexes, see Deploying datastore indexes .

Only application owners and the developer who uploaded the code can download it. If anyone else attempts to download the app, they'll see an error message.

Listing app versions

You can maintain multiple versions of you App Engine application. To list the versions of the default module for your application, use the command:

$ gcloud preview app list-versions default

To list all versions for all modules, use gcloud preview app list-versions without specifying a module.

Deploying datastore indexes

When you deploy an application using gcloud preview app deploy , it includes the app's index.yaml file, if it exists. If the index.yaml file defines an index that doesn't exist yet on App Engine, App Engine creates the new index. Depending on how much data is already in the datastore that needs to be mentioned in the new index, the process of creating the index may take a while. If the app performs a query that requires an index that hasn't finished building yet, the query will raise an exception.

To prevent this, you must ensure that the new version of the app that requires a new index is not the live version of the application until the indexes finish building. One way to do this is to give the app a new version number in app.yaml whenever you add or change an index in index.yaml . The app is uploaded as a new version, and does not become the default version automatically. When your indexes have finished building, you change the default version to the new one using the "Versions" section of the Admin Console .

Another way to ensure that new indexes are built before the new app goes live is to deploy the index.yaml configuration separately before deploying the app. To deployg only the index configuration for an app, use the following command:

$ gcloud preview app deploy DIRECTORY/index.yaml

You can check the status of the app's indexes from the "Indexes" section of the Admin Console . For more information about indexes, see Datastore Index Configuration .

Deploying Task Queue configuration

You can deploy just the configuration for an app's task queues without uploading the full application. To upload the queue.yaml file, use the command:

$ gcloud preview app deploy DIRECTORY/queue.yaml

For more information, see Task Queue Configuration .

Deploying the DoS protection configuration

You can deploy just the configuration for the DoS Protection for an app without uploading the full application. To upload the dos.yaml file, use the command:

$ gcloud preview app deploy DIRECTORY/dos.yaml

For more information, see DoS Protection Service .

Managing scheduled tasks

App Engine supports scheduled tasks (known as cron jobs). You can deploy just the cron jobs configuration for an app without uploading the full application. To upload the cron.yaml file, use the command:

$ gcloud preview app deploy DIRECTORY/cron.yaml

For more information, see the Scheduled Tasks With Cron documentation.

Downloading source code

You can download an application's source code for the default module with the command:

$ gcloud preview app download --version VERSION --output-dir OUTPUT_DIR MODULE default

Only the developer who uploaded the code and the application owner(s) can download it. If anyone other than these parties attempts to download the app, they will see an error message.

Downloading logs

App Engine maintains a log of messages that your application emits using the standard library of the language the app uses, as well as other messages printed to the standard error stream.

App Engine also records each request in the log. Each log level has a fixed buffer size that controls the amount of log information you can access. Normally, you use logging features more at lower log levels; thus, the time window is smaller for log events at these levels. You can browse your app's logs of the last 90 days from the "Logs" section of the Admin Console .

If you wish to perform more detailed analysis of your application's logs, you can download the log data to a file on your computer. To download logs to a file named mylogs.txt , use the following command:

$ gcloud preview app get-logs --version 1 default mylogs.txt

By default, the command downloads log messages from the current calendar day (since midnight Pacific Time) with a log level of INFO or higher (omitting DEBUG level messages). The command overwrites the local log file. You can adjust the number of days, the minimum log level, and whether to overwrite or append to the local log file using command-line options. See below for more information on these options.

You can limit the log messages that are downloaded to just those emitted during request on a given domain name using the --vhost VHOST option. You can use this to download the logs for your live app using a Google Apps domain or http://your_app_id.appspot.com , excluding log messages emitted by versions you are testing on URLs such as http://2.latest.your_app_id.appspot.com . Or you can use it to download just the log messages for a given test domain.

Using an HTTP proxy

If you are running gcloud preview app behind an HTTP proxy, you must tell gcloud preview app the name of the proxy. To set an HTTP proxy for gcloud preview app , set the http_proxy and https_proxy environment variables.

Using Windows (in Command Prompt):

$ set HTTP_PROXY=http://cache.mycompany.com:3128
$ set HTTPS_PROXY=http://cache.mycompany.com:3128
$ gcloud preview app deploy --env-vars HTTP_PROXY,HTTPS_PROXY DIRECTORY

Using the command line in Mac OS X (in Terminal) or Linux:

$ export http_proxy="http://cache.mycompany.com:3128"
$ gcloud preview app deploy --env-vars HTTP_PROXY,HTTPS_PROXY DIRECTORY

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Last updated August 11, 2014.