Connect to private registry using the windows bin

[aymanabollo]

I'm trying to run watchtower bin built for windows as a service to update the running container, the container is built using an image on a private repository.
I tried the following:
.\watchtower.exe -H npipe:////./pipe/docker_engine -i 60 iis1 --debug --trace
but I receive the log like:

time="2021-07-08T02:57:36+02:00" level=debug
time="2021-07-08T02:57:36+02:00" level=debug msg="Sleeping for a second to ensure the docker api client has been properly initialized."
time="2021-07-08T02:57:37+02:00" level=debug msg="Making sure everything is sane before starting"
time="2021-07-08T02:57:37+02:00" level=debug msg="Retrieving running containers"
time="2021-07-08T02:57:37+02:00" level=debug msg="There are no additional watchtower containers"
time="2021-07-08T02:57:37+02:00" level=debug msg="Watchtower HTTP API skipped."
time="2021-07-08T02:57:37+02:00" level=info msg="Watchtower 1.3.0\nUsing no notifications\nOnly checking containers with name \"iis1\"\nScheduling first run: 2021-07-08 02:58:37 +0200 EET\nNote that the first check will be performed in 59 seconds"
time="2021-07-08T02:57:37+02:00" level=warning msg="trace level enabled: log will include sensitive information as credentials and tokens"
time="2021-07-08T02:58:37+02:00" level=debug msg="Checking containers for updated images"
time="2021-07-08T02:58:37+02:00" level=debug msg="Retrieving running containers"
time="2021-07-08T02:58:37+02:00" level=debug msg="Trying to load authentication credentials." container=/iis1 image="privatereg.com/pipesimage:1.5"
time="2021-07-08T02:58:37+02:00" level=debug msg="No credentials for privatereg.com found" config_file="\\config.json"
time="2021-07-08T02:58:37+02:00" level=debug msg="Got image name: privatereg.com/pipesimage:1.5"
time="2021-07-08T02:58:37+02:00" level=debug msg="Checking if pull is needed" container=/iis1 image="privatereg.com/pipesimage:1.5"
time="2021-07-08T02:58:37+02:00" level=debug msg="Building challenge URL" URL="https://privatereg.com/v2/"
time="2021-07-08T02:58:37+02:00" level=debug msg="Got response to challenge request" header="Basic realm=\"Registry Realm\"" status="401 Unauthorized"
time="2021-07-08T02:58:37+02:00" level=debug msg="Could not do a head request for \"privatereg.com/pipesimage:1.5\", falling back to regular pull." container=/iis1 image="privatereg.com/pipesimage:1.5"
time="2021-07-08T02:58:37+02:00" level=debug msg="Reason: no credentials available" container=/iis1 image="privatereg.com/pipesimage:1.5"
time="2021-07-08T02:58:37+02:00" level=debug msg="Pulling image" container=/iis1 image="privatereg.com/pipesimage:1.5"
time="2021-07-08T02:58:37+02:00" level=debug msg="Error pulling image privatereg.com/pipesimage:1.5, Error response from daemon: Get https://privatereg.com/v2/pipesimage/manifests/1.5: no basic auth credentials"
time="2021-07-08T02:58:37+02:00" level=info msg="Unable to update container \"/iis1\": Error response from daemon: Get https://privatereg.com/v2/pipesimage/manifests/1.5: no basic auth credentials. Proceeding to next."
time="2021-07-08T02:58:37+02:00" level=debug msg="Session done: 1 scanned, 0 updated, 1 failed"
time="2021-07-08T02:58:37+02:00" level=debug msg="Scheduled next run: 2021-07-08 02:59:37 +0200 EET"

I couldn't argument to pass the private registry authentication credentials when I used .\watchtower.exe -h

I'm using the watchtower_windows_amd64.zip v1.3.0

Thanks in advance

[piksel]

Watchtower, by default, looks for for the credentials in "/config.json", which should map to "C:\config.json" on windows.
You can modify this by setting the environment variable DOCKER_CONFIG to the directory where yout config.json is stored. In Docker for Desktop, this is normally %USERPROFILE%\.docker.

[aymanabollo]

Thank you for the prompt response, I will try this ASAP,

but is this documented somewhere? if so, I think it would be great and will help me avoid sending questions that might have been already answered before.
thank you so much for your help

[piksel]

It's in the docs, under private-registries.

[aymanabollo]

thank you so much, this is really helpful