docker
Open source

docker

Caution

Promtail has been deprecated and is in Long-Term Support (LTS) through February 28, 2026. Promtail will reach an End-of-Life (EOL) on March 2, 2026. You can find migration resources here.

The docker stage is a parsing stage that reads log lines in the standard format of Docker log files.

Schema

yaml
docker: {}

Unlike most stages, the docker stage provides no configuration options and only supports the specific Docker log format. Each log line from Docker is written as JSON with the following keys:

  1. log: The content of log line
  2. stream: Either stdout or stderr
  3. time: The timestamp string of the log line

Examples

For the given pipeline:

yaml
- docker: {}

Given the following log line:

{"log":"log message\n","stream":"stderr","time":"2019-04-30T02:12:41.8443515Z"}

The following key-value pairs would be created in the set of extracted data:

  • output: log message\n
  • stream: stderr
  • timestamp: 2019-04-30T02:12:41.8443515