Software Architect's Handbook

Logs

Logs give development and operations staff visibility into the application, its behavior, and its exceptions. Logs are an important part of an application and will be discussed further in Chapter 9, Cross-Cutting Concerns.

Cloud-native applications should not be responsible for the routing and storage of its output stream. Rather than writing to or managing log files, each process should treat logs as event streams and simply write its event stream to standard output (stdout) and standard error (stderr).

In a development environment, developers can view the stream to gain insight into the application's behavior. In a production environment, the stream should be captured by the execution environment and then routed to its final destination. ...