Log Output
The log output of the OpenTalk SMTP Mailer can be configured, allowing administrators to control the verbosity and granularity of log messages.
Log level
The verbosity of the log output of the OpenTalk SMTP Mailer is configured by setting a log level. The available log levels are: "error", "warn", "info", "debug" and "trace". Next to those its also possible to set the log level to "off" which completely turns of the logging. By default the log level of the OpenTalk SMTP Mailer is set to "warn". For more information on these log levels see the documentation of the log crate.
Setting the log level
The log level of the OpenTalk SMTP Mailer can be configured with the RUST_LOG environment variable. So for example, if you
want to set the global log level to "debug" you could start the OpenTalk SMTP Mailer with this command:
RUST_LOG=debug opentalk-smtp-mailer
Next to the global log level you can set the log level of specific modules. This is done by providing a key-value pair, where
the key is the name of the module and the key is the log level you want to set for this module. These pairs can be chained
together in a comma seperated list, if you want to set the log level for multiple modules. So for example, if you want to start
the OpenTalk SMTP Mailer with the global log level set to "info" and the log level of the opentalk_smtp_mailer::settings
module set to"warn" you could run the following command:
RUST_LOG=debug,opentalk_smtp_mailer::settings=warn opentalk-smtp-mailer
Special cases
We discovered that some crates we depend on give very verbose output when the log level is set to "debug". This made the log output very hard to navigate and thus we decided to limit the log level of those crates to the default("warn"), even when the global log level is set to a more verbose level. The log level of those crates can still be set explicitly, though.
The crates that are currently handled this way are:
So for example to set the log level of the selectors crate to "debug", while having the global log level also on "debug"
you could start the OpenTalk SMTP Mailer with the following command:
RUST_LOG=debug,selectors=debug opentalk-smtp-mailer