Docker Compose(metrics): Metric Ingestion via Labels

[qclaogui]

Added support for ingesting metrics and controlling the behavior of their ingestion through labels.

The following docker compose service labels are supported:

Metrics

The following service labels are supported for gathering of metrics for docker compose services:

Label	Description
metrics.agent.grafana.com/scrape or prometheus.io/scrape	Boolean whether or not to scrape the service for metrics (default is true).
metrics.agent.grafana.com/scheme or prometheus.io/scheme	The default scraping scheme is http, only support http now.
metrics.agent.grafana.com/path or prometheus.io/path	the default path to scrape is /metrics, this can be specified as a single value which would override, the scrape path being used for all ports attached to the target
metrics.agent.grafana.com/port or prometheus.io/port	the default port to scrape is the target port, this can be specified as a single value which would override the scrape port being used for all ports attached to the target, note that even if an target had multiple targets, the relabel_config targets are deduped before scraping
metrics.agent.grafana.com/tenant	The tenant their metrics should be sent to, this does not necessarily have to be the actual tenantId, it can be a friendly name as well that is simply used to determine if the metrics should be gathered for the current tenant
metrics.agent.grafana.com/job or prometheus.io/job	The job label value to use when collecting their metrics. However, it is common to use an integration or community project where rules / dashboards are provided for you. Oftentimes, this provided assets use hard-coded values for a job label i.e. ...{job="integrations/kubernetes/cadvisor"...} or ...{job="minio-job"...} setting this annotation to that value will allow the provided asset to work out of the box.
metrics.agent.grafana.com/interval or prometheus.io/interval	The default interval to scrape is 15s, this can be override.
metrics.agent.grafana.com/timeout or prometheus.io/timeout	The default timeout for scraping is 10s, this can be override.

Logs

See: #47