json-file logs are not valid JSON

[kara-ryli]

This is probably working as intended, but using docker-compose logs turns out output that isn't valid JSON, e.g.:

nginx | 2010/08/23 15:25:35 [error] This is some random log "with quotes".
app_1 | { "msg": "Hello world" }
app_2 | { "msg": "Hello as well" }

This means that my JSON log entries can't be piped to JQ, and I can't use Amazon's CloudWatch Logs Filters. I'd love if docker-compose allowed me to tweak this so I could have a docker-compose.yml like:

nginx:
  # the default
  log_format: text
app_1:
  log_format: json
app_2:
  log_format: json

And be be able to do something like:

$ docker-compose logs --json
{ "docker": "nginx", "log": "This is some random log \"with quotes\"." }
{ "docker": "app_1", "log": { "msg": "Hello world" } }
{ "docker": "app_2", "log": { "msg": "Hello as well" } }

I'm fine if docker-compose trusts that logs I say are JSON actually are valid JSON. From the look of things, that wouldn't be a terrifically challenging pull request, if you'd entertain it.

[thaJeztah]

I think it's not really recommended to use the output of docker-compose logs for actual production. In addition, the default (json) logging driver used in Docker is not very efficient for high-volume logging.

Docker now supports logging drivers, that allow you to send logs to, for example, fluentd or journald. A new driver was just added, which directly sends container-logs to Amazon CloudWatch; https://github.com/docker/docker/blob/master/docs/reference/logging/awslogs.md; this driver will be part of the docker 1.9 release

[chiefy]

@thaJeztah the issue is that the new logging drivers don't currently work with compose. #1869 So as of right now you're pretty much stuck with syslog or json.

[thaJeztah]

@chiefy ah, you're right, it's not released yet.
I saw that work is in progress to publish "master" builds, so in case you want to try; that might be possible soon: #2154

[ijc]

Issue grooming: Closing, I believe log drivers are now supported docs.