Log Filtering in Heroku

Log Filtering in Heroku

If you only want to fetch logs with a certain source, a certain dyno, or both, you can use the --source (or -s) and --dyno (or -d) filtering arguments:

$ heroku logs --dyno router
2020-03-21T09:43:06.123456+00:00 heroku[router]: at=info method=GET path="/stylesheets/dev-center/library.css" host=devcenter.heroku.com fwd="204.204.204.204" dyno=web.5 connect=1ms service=18ms status=200 bytes=13
2020-03-21T09:43:06.123456+00:00 heroku[router]: at=info method=GET path="/articles/bundler" host=devcenter.heroku.com fwd="204.204.204.204" dyno=web.6 connect=1ms service=18ms status=200 bytes=20375

$ heroku logs --source app
2020-03-21T09:45:47.123456+00:00 app[web.1]: Rendered shared/_search.html.erb (1.0ms)
2020-03-21T09:45:47.123456+00:00 app[web.1]: Completed 200 OK in 83ms (Views: 48.7ms | ActiveRecord: 32.2ms)
2020-03-21T09:45:47.123456+00:00 app[worker.1]: [Worker(host:465cf64e-61c8-46d3-b480-362bfd4ecff9 pid:1)] 1 jobs processed at 23.0330 j/s, 0 failed ...
2020-03-21T09:46:01.123456+00:00 app[web.6]: Started GET "/articles/buildpacks" for 4.1.81.209 at 2012-02-07 09:46:01 +0000

$ heroku logs --source app --dyno worker
2020-03-21T09:47:59.123456+00:00 app[worker.1]: [Worker(host:260cf64e-61c8-46d3-b480-362bfd4ecff9 pid:1)] Article#record_view_without_delay completed after 0.0221
2020-03-21T09:47:59.123456+00:00 app[worker.1]: [Worker(host:260cf64e-61c8-46d3-b480-362bfd4ecff9 pid:1)] 5 jobs processed at 31.6842 j/s, 0 failed ...

You can also combine the filtering switches with --tail to get a real-time stream of filtered output.

$ heroku logs --source app --tail

Happy Coding

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Posted in Heroku, Vietnam Offshore on Mar 21, 2020