NAME
gitremote-helpers - Helper programs to interact with remote repositoriesSYNOPSIS
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 repositories 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.INVOCATION
Remote helper programs are invoked with one or (optionally) two arguments. 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. The GIT_DIR environment variable is set up for the remote helper and can be used to determine where to store additional data or from which directory to invoke auxiliary Git commands.INPUT FORMAT
Git sends the remote helper a list of commands on standard input, one per line. The first command is always the capabilities command, in response to which the remote helper must print a list of the capabilities it supports (see below) followed by a blank line. The response to the capabilities command determines what commands Git uses in the remainder of the command stream.Capabilities
Each remote helper is expected to support only a subset of commands. The operations a helper supports are declared to Git in the response to the capabilities command (see COMMANDS, below).
connect
If a helper advertises connect, Git will use it if possible and fall back
to another capability if the helper requests so when connecting (see the
connect command under COMMANDS). When choosing between push and
export, Git prefers push. Other frontends may have some other
order of preference.
no-private-update
Can attempt to connect to git
receive-pack (for pushing), git upload-pack, etc for communication
using git’s native packfile protocol. This requires a bidirectional,
full-duplex connection.
Supported commands: connect.
stateless-connect
Experimental; for internal use only. Can
attempt to connect to a remote server for communication using git’s
wire-protocol version 2. See the documentation for the stateless-connect
command for more information.
Supported commands: stateless-connect.
push
Can discover remote refs and push local
commits and the history leading up to them to new or existing remote refs.
Supported commands: list for-push, push.
export
Can discover remote refs and push specified
objects from a fast-import stream to remote refs.
Supported commands: list for-push, export.
When using the refspec capability, git
normally updates the private ref on successful push. This update is disabled
when the remote-helper declares the capability no-private-update.
connect
If a helper advertises connect, Git will use it if possible and fall back
to another capability if the helper requests so when connecting (see the
connect command under COMMANDS). When choosing between fetch and
import, Git prefers fetch. Other frontends may have some other
order of preference.
Can try to connect to git upload-pack
(for fetching), git receive-pack, etc for communication using the
Git’s native packfile protocol. This requires a bidirectional,
full-duplex connection.
Supported commands: connect.
stateless-connect
Experimental; for internal use only. Can
attempt to connect to a remote server for communication using git’s
wire-protocol version 2. See the documentation for the stateless-connect
command for more information.
Supported commands: stateless-connect.
fetch
Can discover remote refs and transfer objects
reachable from them to the local object store.
Supported commands: list, fetch.
import
Can discover remote refs and output objects
reachable from them as a stream in fast-import format.
Supported commands: list, import.
check-connectivity
Can guarantee that when a clone is requested,
the received pack is self contained and is connected.
get
Can use the get command to download a
file from a given URI.
option
For specifying settings like verbosity
(how much output to write to stderr) and depth (how much history is
wanted in the case of a shallow clone) that affect how other commands are
carried out.
refspec <refspec>
For remote helpers that implement
import or export, this capability allows the refs to be
constrained to a private namespace, instead of writing to refs/heads or
refs/remotes directly. It is recommended that all importers providing the
import capability use this. It’s mandatory for export.
A helper advertising the capability refspec
refs/heads/*:refs/svn/origin/branches/* is saying that, when it is asked
to import refs/heads/topic, the stream it outputs will update the
refs/svn/origin/branches/topic ref.
This capability can be advertised multiple times. The first applicable refspec
takes precedence. The left-hand of refspecs advertised with this capability
must cover all refs reported by the list command. If no refspec
capability is advertised, there is an implied refspec *:*.
When writing remote-helpers for decentralized version control systems, it is
advised to keep a local copy of the repository to interact with, and to let
the private namespace refs point to this local repository, while the
refs/remotes namespace is used to track the remote repository.
bidi-import
This modifies the import capability.
The fast-import commands cat-blob and ls can be used by
remote-helpers to retrieve information about blobs and trees that already
exist in fast-import’s memory. This requires a channel from fast-import
to the remote-helper. If it is advertised in addition to "import",
Git establishes a pipe from fast-import to the remote-helper’s stdin.
It follows that Git and fast-import are both connected to the
remote-helper’s stdin. Because Git can send multiple commands to the
remote-helper it is required that helpers that use bidi-import buffer
all import commands of a batch before sending data to fast-import. This
is to prevent mixing commands and fast-import responses on the helper’s
stdin.
export-marks <file>
This modifies the export capability,
instructing Git to dump the internal marks table to <file> when
complete. For details, read up on --export-marks=<file> in
git-fast-export(1).
import-marks <file>
This modifies the export capability,
instructing Git to load the marks specified in <file> before processing
any input. For details, read up on --import-marks=<file> in
git-fast-export(1).
signed-tags
This modifies the export capability,
instructing Git to pass --signed-tags=verbatim to
git-fast-export(1). In the absence of this capability, Git will use
--signed-tags=warn-strip.
object-format
This indicates that the helper is able to
interact with the remote side using an explicit hash algorithm
extension.
COMMANDS
Commands are given by the caller on the helper’s standard input, one per line. capabilitiesLists 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 versions using the remote helper to
understand. Any unknown mandatory capability is a fatal error.
Support for this command is mandatory.
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, ":<keyword>
<value>" for a key-value pair, 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.
See REF LIST ATTRIBUTES for a list of currently defined attributes. See REF LIST
KEYWORDS for a list of currently defined keywords.
Supported if the helper has the "fetch" or "import"
capability.
list for-push
Similar to list, except that it is used
if and only if the caller wants to the resulting ref list to prepare push
commands. A helper supporting both push and fetch can use this to distinguish
for which operation the output of list is going to be used, possibly
reducing the amount of work that needs to be performed.
Supported if the helper has the "push" or "export"
capability.
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.
See OPTIONS for a list of currently defined options.
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, terminated 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 output of list with a sha1 may be fetched this way.
Optionally may output a lock <file> line indicating the full path
of a file under $GIT_DIR/objects/pack which is keeping a pack until
refs can be suitably updated. The path must end with .keep. This is a
mechanism to name a <pack,idx,keep> tuple by giving only the keep
component. The kept pack will not be deleted by a concurrent repack, even
though its objects may not be referenced until the fetch completes. The
.keep file will be deleted at the conclusion of the fetch.
If option check-connectivity is requested, the helper must output
connectivity-ok if the clone is self-contained and connected.
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 (if there is only
one reference to push, a single push command is followed by a blank
line). For example, the following would be two batches of push, the
first asking the remote-helper to push the local ref master to the
remote ref master and the local HEAD to the remote
branch, and the second asking to push ref foo to ref bar
(forced update requested by the +).
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 contains an LF.
Supported if the helper has the "push" capability.
import <name>
push refs/heads/master:refs/heads/master push HEAD:refs/heads/branch \n push +refs/heads/foo:refs/heads/bar \n
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.
Just like push, a batch sequence of one or more import is
terminated with a blank line. For each batch of import, the remote
helper should produce a fast-import stream terminated by a done
command.
Note that if the bidi-import capability is used the complete batch
sequence has to be buffered before starting to send data to fast-import to
prevent mixing of commands and fast-import responses on the helper’s
stdin.
Supported if the helper has the "import" capability.
export
Instructs the remote helper that any
subsequent input is part of a fast-import stream (generated by git
fast-export) containing objects which should be pushed to the remote.
Especially useful for interoperability with a foreign versioning system.
The export-marks and import-marks capabilities, if specified,
affect this command in so far as they are passed on to git fast-export,
which then will load/store a table of marks for local objects. This can be
used to implement for incremental operations.
Supported if the helper has the "export" 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 transport 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.
stateless-connect <service>
Experimental; for internal use only. Connects
to the given remote service for communication using git’s wire-protocol
version 2. Valid replies to this command are empty line (connection
established), fallback (no smart transport 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 the service starts. Messages (both
request and response) must consist of zero or more PKT-LINEs, terminating in a
flush packet. Response messages will then have a response end packet after the
flush packet to indicate the end of a response. The client must not expect the
server to store any state in between request-response pairs. After the
connection ends, the remote helper exits.
Supported if the helper has the "stateless-connect" capability.
get <uri> <path>
Downloads the file from the given
<uri> to the given <path>. If
<path>.temp exists, then Git assumes that the .temp file
is a partial download from a previous attempt and will resume the download
from that position.
REF LIST ATTRIBUTES
The list command produces a list of refs in which each ref may be followed by a list of attributes. The following ref list attributes are defined. unchangedThis ref is unchanged since the last import or
fetch, although the helper cannot necessarily determine what value that
produced.
REF LIST KEYWORDS
The list command may produce a list of key-value pairs. The following keys are defined. object-formatThe refs are using the given hash algorithm.
This keyword is only used if the server and client both support the
object-format extension.
OPTIONS
The following options are defined and (under suitable circumstances) set by Git if the remote helper has the option capability. 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 transport helper during a command.
option depth <depth>
Deepens the history of a shallow
repository.
'option deepen-since <timestamp>
Deepens the history of a shallow repository
based on time.
'option deepen-not <ref>
Deepens the history of a shallow repository
excluding ref. Multiple options add up.
option deepen-relative {'true|false}
Deepens the history of a shallow repository
relative to current boundary. Only valid when used with "option
depth".
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.
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.
option check-connectivity {true|false}
Request the helper to check connectivity of a
clone.
option force {true|false}
Request the helper to perform a force update.
Defaults to false.
option cloning {true|false}
Notify the helper this is a clone request
(i.e. the current repository is guaranteed empty).
option update-shallow {true|false}
Allow to extend .git/shallow if the new refs
require it.
option pushcert {true|false}
GPG sign pushes.
'option push-option <string>
Transmit <string> as a push option. As
the push option must not contain LF or NUL characters, the string is not
encoded.
option from-promisor {true|false}
Indicate that these objects are being fetched
from a promisor.
option no-dependents {true|false}
Indicate that only the objects wanted need to
be fetched, not their dependents.
option atomic {true|false}
When pushing, request the remote server to
update refs in a single atomic transaction. If successful, all refs will be
updated, or none will. If the remote side does not support this capability,
the push will fail.
option object-format {true|algorithm}
If true, indicate that the caller wants
hash algorithm information to be passed back from the remote. This mode is
used when fetching refs.
If set to an algorithm, indicate that the caller wants to interact with the
remote side using that algorithm.
SEE ALSO
git-remote(1)GIT
Part of the git(1) suite02/28/2023 | Git 2.39.2 |