runtime

runtime

Global logging

Additional to the (global) --log= option, the runtime also has the concept of a global logfile.

The purpose of this secondary logfile is twofold:

• To allow all log output to be recorded in a non-container-specific path.

  This is particularly useful under container managers such as Docker where if a container fails to start, the container-specific directory (which contains the --log= logfile) will be deleted on error, making debugging a challenge.

• To collate the log output from all runtimes in a single place.

The global logfile comprises one line per entry. Each line contains the following fields separated by colons:

• timestamp
• PID
• program name
• log level
• log message

The global logfile records all log output sent to the standard logfile.

Note that if output is disabled for the standard logfile, the global log will still record all logging calls the runtime makes.

The global logfile is disabled by default. It can be enabled either in the configuration.toml configuration file or by setting the CC_RUNTIME_GLOBAL_LOG environment variable to a suitable path. The environment variable takes priority over the configuration file.

The global logfile path must be specified as an absolute path. If the directory specified by the logfile path does not exist, the runtime will attempt to create it.

It is the Administrator's responsibility to ensure there is sufficient space for the global log.