App Log streaming in Cloud Foundry

When you bind an application to an instance of an applicable service, Cloud Foundry streams logs for the bound application to the service instance.

• Logs for all apps bound to a log consuming service instance are streamed to that instance.
• Logs for an app bound to multiple log consuming service instances are streamed to all instances.

To enable this functionality, a service broker must implement the following:

1. In the catalog endpoint, the broker must include requires: syslog_drain. This minor security measure validates that a service returning a syslog_drain_url in response to the bind operation has also declared that it expects log streaming. If the broker does not include requires: syslog_drain, and the bind request returns a value for syslog_drain_url, Cloud Foundry will return an error for the bind operation.

2. In response to a bind request, the broker should return a value for syslog_drain_url. The syslog URL has a scheme of syslog, syslog-tls, or https and can include a port number. For example:

   "syslog_drain_url": "syslog://logs.example.com:1234"

How does it work?

1. Service broker returns a value for syslog_drain_url in response to bind.
2. Loggregator periodically polls an internal Cloud Controller endpoint for updates.
3. Upon discovering a new syslog_drain_url, Loggregator identifies the associated app.
4. Loggregator streams app logs for that app to the locations specified by the service instances’ syslog_drain_urls.

You can manually configure app logs to be streamed to a location of your choice using user-provided service instances.

For details, see Using Third-Party Log Management Services.