GIT-REMOTE-HELPERS(1)GIT-REMOTE-HELPERS(1)NAMEgit-remote-helpers - Helper programs to interact with remote reposito-
ries
SYNOPSIS
git remote-<transport> <repository> [<URL>]
DESCRIPTION
Remote helper programs are normally not used directly by end users, but
they are invoked by git when it needs to interact with remote reposito-
ries git does not support natively. A given helper will implement a
subset of the capabilities documented here. When git needs to interact
with a repository using a remote helper, it spawns the helper as an
independent process, sends commands to the helper’s standard
input, and expects results from the helper’s standard output.
Because a remote helper runs as an independent process from git, there
is no need to re-link git to add a new helper, nor any need to link the
helper with the implementation of git.
Every helper must support the "capabilities" command, which git will
use to determine what other commands the helper will accept. Other com-
mands generally concern facilities like discovering and updating remote
refs, transporting objects between the object database and the remote
repository, and updating the local object store.
Helpers supporting the fetch capability can discover refs from the
remote repository and transfer objects reachable from those refs to the
local object store. Helpers supporting the push capability can transfer
local objects to the remote repository and update remote refs.
Git comes with a "curl" family of remote helpers, that handle various
transport protocols, such as git-remote-http, git-remote-https,
git-remote-ftp and git-remote-ftps. They implement the capabilities
fetch, option, and push.
INVOCATION
Remote helper programs are invoked with one or (optionally) two argu-
ments. The first argument specifies a remote repository as in git; it
is either the name of a configured remote or a URL. The second argument
specifies a URL; it is usually of the form <transport>://<address>, but
any arbitrary string is possible.
When git encounters a URL of the form <transport>://<address>, where
<transport> is a protocol that it cannot handle natively, it automati-
cally invokes git remote-<transport> with the full URL as the second
argument. If such a URL is encountered directly on the command line,
the first argument is the same as the second, and if it is encountered
in a configured remote, the first argument is the name of that remote.
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A URL of the form <transport>::<address> explicitly instructs git to
invoke git remote-<transport> with <address> as the second argument. If
such a URL is encountered directly on the command line, the first argu-
ment is <address>, and if it is encountered in a configured remote, the
first argument is the name of that remote.
Additionally, when a configured remote has remote.<name>.vcs set to
<transport>, git explicitly invokes git remote-<transport> with <name>
as the first argument. If set, the second argument is
remote.<name>.url; otherwise, the second argument is omitted.
COMMANDS
Commands are given by the caller on the helper’s standard input,
one per line.
capabilities
Lists the capabilities of the helper, one per line, ending with
a blank line. Each capability may be preceded with *, which
marks them mandatory for git version using the remote helper to
understand (unknown mandatory capability is fatal error).
list Lists the refs, one per line, in the format "<value> <name>
[<attr> ...]". The value may be a hex sha1 hash, "@<dest>" for a
symref, or "?" to indicate that the helper could not get the
value of the ref. A space-separated list of attributes follows
the name; unrecognized attributes are ignored. The list ends
with a blank line.
If push is supported this may be called as list for-push to
obtain the current refs prior to sending one or more push com-
mands to the helper.
option <name> <value>
Sets the transport helper option <name> to <value>. Outputs a
single line containing one of ok (option successfully set),
unsupported (option not recognized) or error <msg> (option
<name> is supported but <value> is not valid for it). Options
should be set before other commands, and may influence the
behavior of those commands.
Supported if the helper has the "option" capability.
fetch <sha1> <name>
Fetches the given object, writing the necessary objects to the
database. Fetch commands are sent in a batch, one per line, ter-
minated with a blank line. Outputs a single blank line when all
fetch commands in the same batch are complete. Only objects
which were reported in the ref list with a sha1 may be fetched
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this way.
Optionally may output a lock <file> line indicating a file under
GIT_DIR/objects/pack which is keeping a pack until refs can be
suitably updated.
Supported if the helper has the "fetch" capability.
push +<src>:<dst>
Pushes the given local <src> commit or branch to the remote
branch described by <dst>. A batch sequence of one or more push
commands is terminated with a blank line.
Zero or more protocol options may be entered after the last push
command, before the batch’s terminating blank line.
When the push is complete, outputs one or more ok <dst> or error
<dst> <why>? lines to indicate success or failure of each pushed
ref. The status report output is terminated by a blank line. The
option field <why> may be quoted in a C style string if it con-
tains an LF.
Supported if the helper has the "push" capability.
import <name>
Produces a fast-import stream which imports the current value of
the named ref. It may additionally import other refs as needed
to construct the history efficiently. The script writes to a
helper-specific private namespace. The value of the named ref
should be written to a location in this namespace derived by
applying the refspecs from the "refspec" capability to the name
of the ref.
Especially useful for interoperability with a foreign versioning
system.
Supported if the helper has the "import" capability.
connect <service>
Connects to given service. Standard input and standard output of
helper are connected to specified service (git prefix is
included in service name so e.g. fetching uses git-upload-pack
as service) on remote side. Valid replies to this command are
empty line (connection established), fallback (no smart trans-
port support, fall back to dumb transports) and just exiting
with error message printed (can’t connect, don’t
bother trying to fall back). After line feed terminating the
positive (empty) response, the output of service starts. After
the connection ends, the remote helper exits.
Supported if the helper has the "connect" capability.
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If a fatal error occurs, the program writes the error message to
stderr and exits. The caller should expect that a suitable error
message has been printed if the child closes the connection
without completing a valid response for the current command.
Additional commands may be supported, as may be determined from
capabilities reported by the helper.
CAPABILITIES
fetch, option, push, import, connect
This helper supports the corresponding command with the same
name.
refspec spec
When using the import command, expect the source ref to have
been written to the destination ref. The earliest applicable
refspec takes precedence. For example "refs/heads/:refs/svn/ori-
gin/branches/" means that, after an "import refs/heads/name",
the script has written to refs/svn/origin/branches/name. If this
capability is used at all, it must cover all refs reported by
the list command; if it is not used, it is effectively ":"
REF LIST ATTRIBUTES
for-push
The caller wants to use the ref list to prepare push commands. A
helper might chose to acquire the ref list by opening a differ-
ent type of connection to the destination.
unchanged
This ref is unchanged since the last import or fetch, although
the helper cannot necessarily determine what value that pro-
duced.
OPTIONS
option verbosity <N>
Changes the verbosity of messages displayed by the helper. A
value of 0 for N means that processes operate quietly, and the
helper produces only error output. 1 is the default level of
verbosity, and higher values of N correspond to the number of -v
flags passed on the command line.
option progress {true|false}
Enables (or disables) progress messages displayed by the trans-
port helper during a command.
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option depth <depth>
Deepens the history of a shallow repository.
option followtags {true|false}
If enabled the helper should automatically fetch annotated tag
objects if the object the tag points at was transferred during
the fetch command. If the tag is not fetched by the helper a
second fetch command will usually be sent to ask for the tag
specifically. Some helpers may be able to use this option to
avoid a second network connection.
option dry-run {true|false}: If true, pretend the operation com-
pleted successfully, but don’t actually change any reposi-
tory data. For most helpers this only applies to the push, if
supported.
option servpath <c-style-quoted-path>
Sets service path (--upload-pack, --receive-pack etc.) for next
connect. Remote helper may support this option, but must not
rely on this option being set before connect request occurs.
SEE ALSOgit-remote(1)DOCUMENTATION
Documentation by Daniel Barkalow and Ilari Liusvaara
GIT
Part of the git(1) suite
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