From 6ee9d8a187719ce051609da2284720a931f082d3 Mon Sep 17 00:00:00 2001 From: David Calavera Date: Sun, 7 Feb 2016 19:55:17 -0500 Subject: [PATCH] Client credentials store. This change implements communication with an external credentials store, ala git-credential-helper. The client falls back the plain text store, what we're currently using, if there is no remote store configured. It shells out to helper program when a credential store is configured. Those programs can be implemented with any language as long as they follow the convention to pass arguments and information. There is an implementation for the OS X keychain in https://github.com/calavera/docker-credential-helpers. That package also provides basic structure to create other helpers. Signed-off-by: David Calavera --- docs/reference/commandline/login.md | 74 +++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+) diff --git a/docs/reference/commandline/login.md b/docs/reference/commandline/login.md index faf3615a..b20fb6cd 100644 --- a/docs/reference/commandline/login.md +++ b/docs/reference/commandline/login.md @@ -38,3 +38,77 @@ credentials. When you log in, the command stores encoded credentials in > **Note**: When running `sudo docker login` credentials are saved in `/root/.docker/config.json`. > + +## Credentials store + +The Docker Engine can keep user credentials in an external credentials store, +such as the native keychain of the operating system. Using an external store +is more secure than storing credentials in the Docker configuration file. + +To use a credentials store, you need an external helper program to interact +with a specific keychain or external store. Docker requires the helper +program to be in the client's host `$PATH`. + +This is the list of currently available credentials helpers and where +you can download them from: + +- Apple OS X keychain: https://github.com/docker/docker-credential-helpers/releases +- Microsoft Windows Credential Manager: https://github.com/docker/docker-credential-helpers/releases + +### Usage + +You need to speficy the credentials store in `HOME/.docker/config.json` +to tell the docker engine to use it: + +```json +{ + "credsStore": "osxkeychain" +} +``` + +If you are currently logged in, run `docker logout` to remove +the credentials from the file and run `docker login` again. + +### Protocol + +Credential helpers can be any program or script that follows a very simple protocol. +This protocol is heavily inspired by Git, but it differs in the information shared. + +The helpers always use the first argument in the command to identify the action. +There are only three possible values for that argument: `store`, `get`, and `erase`. + +The `store` command takes a JSON payload from the standard input. That payload carries +the server address, to identify the credential, the user name and the password. +This is an example of that payload: + +```json +{ + "ServerURL": "https://index.docker.io/v1", + "Username": "david", + "Password": "passw0rd1" +} +``` + +The `store` command can write error messages to `STDOUT` that the docker engine +will show if there was an issue. + +The `get` command takes a string payload from the standard input. That payload carries +the server address that the docker engine needs credentials for. This is +an example of that payload: `https://index.docker.io/v1`. + +The `get` command writes a JSON payload to `STDOUT`. Docker reads the user name +and password from this payload: + +```json +{ + "Username": "david", + "Password": "passw0rd1" +} +``` + +The `erase` command takes a string payload from `STDIN`. That payload carries +the server address that the docker engine wants to remove credentials for. This is +an example of that payload: `https://index.docker.io/v1`. + +The `erase` command can write error messages to `STDOUT` that the docker engine +will show if there was an issue.