Configuring the application process with a Procfile - AWS Elastic Beanstalk
Using a Procfile on Amazon Linux AMI (preceding Amazon Linux 2)
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Configuring the application process with a Procfile

To specify custom commands to start a Go application, include a file called Procfile at the root of your source bundle.

For details about writing and using a Procfile, expand the Buildfile and Procfile section in Extending Elastic Beanstalk Linux platforms.

Example Procfile

web: bin/server
queue_process: bin/queue_processor
foo: bin/fooapp

You must call the main application web, and list it as the first command in your Procfile. Elastic Beanstalk exposes the main web application on the root URL of the environment; for example, http://my-go-env.elasticbeanstalk.com.

Elastic Beanstalk also runs any application whose name does not have the web_ prefix, but these applications are not available from outside of your instance.

Elastic Beanstalk expects processes run from the Procfile to run continuously. Elastic Beanstalk monitors these applications and restarts any process that terminates. For short-running processes, use a Buildfile command.

Using a Procfile on Amazon Linux AMI (preceding Amazon Linux 2)

If your Elastic Beanstalk Go environment uses an Amazon Linux AMI platform version (preceding Amazon Linux 2), read the additional information in this section.

Elastic Beanstalk configures the nginx proxy to forward requests to your application on the port number specified in the PORT environment property for your application. Your application should always listen on that port. You can access this variable within your application by calling the os.Getenv("PORT") method.

Elastic Beanstalk uses the port number specified in the PORT environment property for the port for the first application in the Procfile, and then increments the port number for each subsequent application in the Procfile by 100. If the PORT environment property is not set, Elastic Beanstalk uses 5000 for the initial port.

In the preceding example, the PORT environment property for the web application is 5000, the queue_process application is 5100, and the foo application is 5200.

You can specify the initial port by setting the PORT option with the aws:elasticbeanstalk:application:environment namespace, as shown in the following example. 

option_settings:
  - namespace:  aws:elasticbeanstalk:application:environment
    option_name:  PORT
    value:  <first_port_number>

For more information about setting environment properties for your application, see Option settings.