Misleading messages when login/logout with docker-credential-pass about common HOT 6 OPEN

Interested in opening a PR to make this work better?

from common.

Yes I can open one and at the same time I need to know what result you expect.

To compare docker and podman I have used ~/.docker/config.json with:

{
    "credHelpers": {
        "foo.io": "pass"
    }
}

Actual behavior:

With docker:

$ docker-credential-pass list
{}

$ docker login foo.io # docker asks for username and password
Username: my_username
Password:
Login Succeeded # docker stores credential in pass database

$ docker-credential-pass list
{"foo.io":"my_username"}

$ docker login foo.io
Authenticating with existing credentials...
Login Succeeded

$ docker logout foo.io
Removing login credentials for foo.io # docker removes credential in pass database

$ docker-credential-pass list
{}

With podman:

$ docker-credential-pass list
{}

$ podman login foo.io # podman asks for username and password
Username: my_username
Password:
Login Succeeded # podman stores credential in base64 in `/run/user/uid/containers/auth.json`

$ docker-credential-pass list
{}

$ podman logout foo.io
Removed login credentials for foo.io

$ docker-credential-pass store
{"ServerURL":"foo.io","Username":"my_username","Secret":"my_secret"}

$ docker-credential-pass list
{"foo.io":"my_username"}

$ podman login foo.io
Authenticating with existing credentials...
Existing credentials are valid. Already logged in to foo.io

$ podman logout foo.io
Not logged into foo.io with current tool. Existing credentials were established via docker login. Please use docker logout instead.

$ docker-credential-pass list
{"foo.io":"my_username"}

To sum up docker stores the password in pass on login if not already present and delete the password in pass on logout while podman retrieves credentials with pass if present and fallback to base64 if not and podman never updates pass database.

Side note:

In my tests I had to specify export GPG_TTY=$(tty) to be able to enter my passphrase with podman because it starts a specific gpg-agent and does not use the global one:

# before any podman commands that need access to registry

$ ps -fp "$(pgrep -d, -x gpg-agent)"
UID                  PID    PPID  C STIME TTY          TIME CMD
my_username         4010    2420  0 08:39 ?        00:00:05 /usr/bin/gpg-agent --supervised

# after a podman command that needs access to registry

$ ps -fp "$(pgrep -d, -x gpg-agent)"
UID                  PID    PPID  C STIME TTY          TIME CMD
my_username         4010    2420  0 08:39 ?        00:00:05 /usr/bin/gpg-agent --supervised
my_username        33240    2420  1 09:31 ?        00:00:00 gpg-agent --homedir /home/my_username/.gnupg --use-standard-socket --daemon

Proposal:

For me, docker/podman login/logout should not be used when used with pass (this assumes that people use a passphrase) or only as a simpler alternative to docker-credential-pass store/erase.

Ideally it is not only messages that should change, I propose to:

• document that login/logout actually store and delete credentials and that they may not be necessary when the password is stored with pass
• only use the credentials helper specified for a registry and triggers an error if not possible (ie no fallback)
• let podman use global gpg-agent and not a specific one
• change podman login/logout (behavior and messages) to match docker as you want to be compatible

from common.

Podman will not use the dockerfile location by default.

You need to either set DOCKER_HOST or use --auth-file to point at the config.

podman login --auth-file ~/.docker/config.json foo.io

from common.

Podman will not use the dockerfile location by default.

You mean to store credentials in the authentication file or to read authentication file? If the latter,
based on my tests and the code I would say that podman fallbacks by default. Login() calls config.GetCredentials() that explicitly states:

GetCredentials returns the registry credentials stored in the
registry-specific credential helpers or in the default global credentials
helpers with falling back to using either auth.json
file or .docker/config.json, including support for OAuth2 and IdentityToken.
If an entry is not found, an empty struct is returned.

from common.

Are you seeing the expected behaviour?

from common.

I do not get it. If you talk about ~/.docker/config.json yes podman uses it as fallbacks, if you talk about the issue then no, there was no replies about my proposal.

from common.