git-credential






git‐credential − Retrieve and store user credentials



git credential <fill|approve|reject>




Git has an internal interface for storing and retrieving
credentials from system−specific helpers, as well as
prompting the user for usernames and passwords. The
git−credential command exposes this interface to scripts
which may want to retrieve, store, or prompt for credentials
in the same manner as Git. The design of this scriptable
interface models the internal C API; see credential.h for
more background on the concepts.

git−credential takes an "action" option on the command−line
(one of fill, approve, or reject) and reads a credential
description on stdin (see INPUT/OUTPUT FORMAT).

If the action is fill, git−credential will attempt to add
"username" and "password" attributes to the description by
reading config files, by contacting any configured
credential helpers, or by prompting the user. The username
and password attributes of the credential description are
then printed to stdout together with the attributes already
provided.

If the action is approve, git−credential will send the
description to any configured credential helpers, which may
store the credential for later use.

If the action is reject, git−credential will send the
description to any configured credential helpers, which may
erase any stored credential matching the description.

If the action is approve or reject, no output should be
emitted.



An application using git−credential will typically use git
credential following these steps:

  1. Generate a credential description based on the context.

     For example, if we want a password for
     https://example.com/foo.git, we might generate the
     following credential description (don’t forget the
     blank line at the end; it tells git credential that the
     application finished feeding all the information it
     has):









                             ‐2‐


          protocol=https
          host=example.com
          path=foo.git

  2. Ask git−credential to give us a username and password
     for this description. This is done by running git
     credential fill, feeding the description from step (1)
     to its standard input. The complete credential
     description (including the credential per se, i.e. the
     login and password) will be produced on standard
     output, like:

          protocol=https
          host=example.com
          username=bob
          password=secr3t

     In most cases, this means the attributes given in the
     input will be repeated in the output, but Git may also
     modify the credential description, for example by
     removing the path attribute when the protocol is
     HTTP(s) and credential.useHttpPath is false.

     If the git credential knew about the password, this
     step may not have involved the user actually typing
     this password (the user may have typed a password to
     unlock the keychain instead, or no user interaction was
     done if the keychain was already unlocked) before it
     returned password=secr3t.

  3. Use the credential (e.g., access the URL with the
     username and password from step (2)), and see if it’s
     accepted.

  4. Report on the success or failure of the password. If
     the credential allowed the operation to complete
     successfully, then it can be marked with an "approve"
     action to tell git credential to reuse it in its next
     invocation. If the credential was rejected during the
     operation, use the "reject" action so that git
     credential will ask for a new password in its next
     invocation. In either case, git credential should be
     fed with the credential description obtained from step
     (2) (which also contain the ones provided in step (1)).



git credential reads and/or writes (depending on the action
used) credential information in its standard input/output.
This information can correspond either to keys for which git
credential will obtain the login information (e.g. host,
protocol, path), or to the actual credential data to be
obtained (username/password).










                             ‐3‐


The credential is split into a set of named attributes, with
one attribute per line. Each attribute is specified by a
key−value pair, separated by an = (equals) sign, followed by
a newline.

The key may contain any bytes except =, newline, or NUL. The
value may contain any bytes except newline or NUL.

In both cases, all bytes are treated as−is (i.e., there is
no quoting, and one cannot transmit a value with newline or
NUL in it). The list of attributes is terminated by a blank
line or end−of−file.

Git understands the following attributes:

     protocol
     The protocol over which the credential will be used
     (e.g., https).

     host
     The remote hostname for a network credential. This
     includes the port number if one was specified (e.g.,
     "example.com:8088").

     path
     The path with which the credential will be used. E.g.,
     for accessing a remote https repository, this will be
     the repository’s path on the server.

     username
     The credential’s username, if we already have one
     (e.g., from a URL, the configuration, the user, or from
     a previously run helper).

     password
     The credential’s password, if we are asking it to be
     stored.

     url
     When this special attribute is read by git credential,
     the value is parsed as a URL and treated as if its
     constituent parts were read (e.g.,
     url=https://example.com would behave as if
     protocol=https and host=example.com had been provided).
     This can help callers avoid parsing URLs themselves.

     Note that specifying a protocol is mandatory and if the
     URL doesn’t specify a hostname (e.g.,
     "cert:///path/to/file") the credential will contain a
     hostname attribute whose value is an empty string.

     Components which are missing from the URL (e.g., there
     is no username in the example above) will be left
     unset.









                             ‐4‐