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| -rw-r--r-- | README.md | 28 |
1 files changed, 23 insertions, 5 deletions
diff --git a/README.md b/README.md index 63ac2655687a..00db058e8850 100644 --- a/README.md +++ b/README.md @@ -22,6 +22,8 @@ configuration as authentication tokens are retrieved from the in Stackdriver * `journaldriver` can be used outside of GCP by configuring static credentials +* `journaldriver` will recognise journald's log priority levels and + convert them into equivalent Stackdriver log severity levels ## Usage on Google Cloud Platform @@ -60,6 +62,24 @@ performed: `journaldriver` if unset, but it is recommended to - for example - set it to the machine hostname. +## Log levels / severities / priorities + +`journaldriver` recognises [journald's priorities][] and converts them +into [equivalent severities][] in Stackdriver. Both sets of values +correspond to standard `syslog` priorities. + +The easiest way to emit log messages with priorites from an +application is to use [priority prefixes][], which are compatible with +structured log messages. + +For example, to emit a simple warning message (structured and +unstructured): + +``` +$ echo '<4>{"fnord":true, "msg":"structured log (warning)"}' | systemd-cat +$ echo '<4>unstructured log (warning)' | systemd-cat +``` + ## NixOS module At Aprila we deploy all of our software using [NixOS][], including @@ -87,13 +107,11 @@ services.journaldriver = { **Note**: The `journaldriver`-module is not yet included in a stable release of NixOS, but it is available on the `unstable`-channel. -## Upcoming features: - -* `journaldriver` will be added to [nixpkgs][] with a complementary - [NixOS][] module for easy configuration. - [Stackdriver Logging]: https://cloud.google.com/logging/ [metadata server]: https://cloud.google.com/compute/docs/storing-retrieving-metadata [Google's documentation]: https://cloud.google.com/logging/docs/access-control [NixOS]: https://nixos.org/ [contains a module]: https://github.com/NixOS/nixpkgs/pull/42134 +[journald's priorities]: http://0pointer.de/public/systemd-man/sd-daemon.html +[equivalent severities]: https://cloud.google.com/logging/docs/reference/v2/rest/v2/LogEntry#logseverity +[priority prefixes]: http://0pointer.de/public/systemd-man/sd-daemon.html |