By default, enabling this mode prevents periodic polls (i.e. what is specified using `--interval` or `--schedule`). To run periodic updates regardless, pass `--http-api-periodic-polls`.
Notice that there is an environment variable named WATCHTOWER_HTTP_API_TOKEN. To prevent external services from accidentally triggering image updates, all of the requests have to contain a "Token" field, valued as the token defined in WATCHTOWER_HTTP_API_TOKEN, in their headers. In this case, there is a port bind to the host machine, allowing to request localhost:8080 to reach Watchtower. The following `curl` command would trigger an image update: