Adds config to disable HTTP and GRPC server in Promtail.

[cyriltovena]

Fixes #1991.

Signed-off-by: Cyril Tovena cyril.tovena@gmail.com

[slim-bean]

LGTM!

[candlerb]

LGTM too.

Regarding the sample configs which show grpc_listen_port: 0 - were these really intended to suggest it's a good idea to run grpc on a random port? I wonder why?

[cyriltovena]

Which config ? it should not !

[candlerb]

• https://github.com/grafana/loki/blob/master/cmd/promtail/promtail-local-config.yaml#L3
• https://github.com/grafana/loki/blob/master/cmd/promtail/promtail-docker-config.yaml#L3
• https://github.com/grafana/loki/blob/master/docs/clients/promtail/configuration.md#example-static-config
• https://github.com/grafana/loki/blob/master/docs/clients/promtail/configuration.md#example-journal-config
• https://github.com/grafana/loki/blob/master/docs/clients/promtail/configuration.md#example-syslog-config

[cyriltovena]

Yes each of those doesn't require GRPC. We could just remove it but binding to a random port ensure we don't fail for a default port in use.

[candlerb]

Would it make sense to have separate http_disable and grpc_disable instead?

[cyriltovena]

Yes it would but we're using a library and that would need to be done there.