Flownative Promtail Image

A Docker image providing Promtail for Beach, Local Beach and other purposes. Compared to the official Promtail image, this one provides an opinionated configuration which can be controlled through environment variables.

Sending logs from Local Beach

  addon-promtail:
    image: flownative/promtail
    container_name: ${BEACH_PROJECT_NAME:?Please specify a Beach project name as BEACH_PROJECT_NAME}_addon-promtail
    networks:
      - local_beach
    volumes:
      - ./Data/Logs:/application/Data/Logs:delegated
    environment:
      - PROMTAIL_CLIENT_URL=http://loki_loki_1:3100/loki/api/v1/push
      - PROMTAIL_LABELS=eyJqb2IiOiAibXktam9iIiwgInNldmVyaXR5IjogImZpbmUifQ==
      - PROMTAIL_LABEL_HOST=localbeach-${BEACH_PROJECT_NAME}

Testing with docker run

Create a directory "test" on your local machine. Within that directory create a file "test.log".

Then run Promtail with docker run:

docker run -v $(pwd)/logs:/logs \
  -e PROMTAIL_SCRAPE_PATH=/logs/test.log \
  -e PROMTAIL_CLIENT_URL=https://logs-prod-us-central1.grafana.net/loki/api/v1/push \
  -e PROMTAIL_BASIC_AUTH_USERNAME=loki-username \
  -e PROMTAIL_BASIC_AUTH_PASSWORD=loki-password \
  -e PROMTAIL_LABELS=eyJqb2IiOiAibXktam9iIiwgInNldmVyaXR5IjogImZpbmUifQ== \ 
  flownative/promtail

In a separate terminal, add test content to the log file, for example with echo "some test" >> logs/test.log.

Environment variables

Variable Name	Type	Default	Description
PROMTAIL_CLIENT_URL	string	http://loki_loki_1:3100/loki/api/v1/push	URL pointing to the Loki push endpoint
PROMTAIL_LABEL_HOST	string	$(hostname)	Value of the label "host" which is added to all log entries
PROMTAIL_LABELS_BASE64	string		Additional labels to set. Must be a BASE64-encoded JSONs string. JSON example: {"job": "my-job", "severity": "fine"}
PROMTAIL_CLIENT_TENANT_ID	string		An optional tenant id to sent as the X-Scope-OrgID-header
PROMTAIL_BASIC_AUTH_USERNAME	string		Username to use for basic auth, if required by Loki
PROMTAIL_BASIC_AUTH_PASSWORD	string		Password to use for basic auth, if required by Loki
PROMTAIL_SCRAPE_PATH	string	/application/Data/Logs/*.log	Path leading to log files to be scraped; supports glob syntax

Security aspects

This image is designed to run as a non-root container. When you are running this image with Docker or in a Kubernetes context, you can take advantage of the non-root approach by disallowing privilege escalation:

$ docker run flownative/promtail:latest --security-opt=no-new-privileges