gitremote-helpers(1) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | INVOCATION | INPUT FORMAT | COMMANDS | REF LIST ATTRIBUTES | OPTIONS | SEE ALSO | GIT | COLOPHON

GITREMOTE-HELPERS(1)           Git Manual           GITREMOTE-HELPERS(1)

NAME         top

       gitremote-helpers - Helper programs to interact with remote
       repositories

SYNOPSIS         top

       git remote-<transport> <repository> [<URL>]

DESCRIPTION         top

       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.

       Every helper must support the "capabilities" command, which Git
       uses to determine what other commands the helper will accept.
       Those other commands can be used to discover and update remote
       refs, transport objects between the object database and the
       remote repository, and update the local object store.

       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         top

       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.

       When Git encounters a URL of the form <transport>://<address>,
       where <transport> is a protocol that it cannot handle natively,
       it automatically 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.

       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 argument 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.

INPUT FORMAT         top

       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.

       The command stream is terminated by a blank line. In some cases
       (indicated in the documentation of the relevant commands), this
       blank line is followed by a payload in some other protocol (e.g.,
       the pack protocol), while in others it indicates the end of
       input.

   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).

       In the following, we list all defined capabilities and for each
       we list which commands a helper with that capability must
       provide.

       Capabilities for Pushing
           connect
               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.

           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
               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.

       Capabilities for Fetching
           connect
               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.

           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.

       Miscellaneous capabilities
           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.

COMMANDS         top

       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 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, 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.

           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 a file
           under GIT_DIR/objects/pack which is keeping a pack until refs
           can be suitably updated.

           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 +).

               push refs/heads/master:refs/heads/master
               push HEAD:refs/heads/branch
               \n
               push +refs/heads/foo:refs/heads/bar
               \n

           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>
           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. 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.

       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.

REF LIST ATTRIBUTES         top

       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.

       unchanged
           This ref is unchanged since the last import or fetch,
           although the helper cannot necessarily determine what value
           that produced.

OPTIONS         top

       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.

       option dry-run {true|false}: If true, pretend the operation
       completed successfully, but don’t actually change any repository
       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.

       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.

SEE ALSO         top

       git-remote(1)

       git-remote-ext(1)

       git-remote-fd(1)

       git-remote-testgit(1)

       git-fast-import(1)

GIT         top

       Part of the git(1) suite

COLOPHON         top

       This page is part of the git (Git distributed version control
       system) project.  Information about the project can be found at
       ⟨http://git-scm.com/⟩.  If you have a bug report for this manual
       page, see ⟨http://git-scm.com/community⟩.  This page was obtained
       from the project's upstream Git repository
       ⟨https://github.com/git/git.git⟩ on 2021-04-01.  (At that time,
       the date of the most recent commit that was found in the
       repository was 2021-03-30.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to
       man-pages@man7.org

Git 2.19.1.593.gc670b1         10/28/2018           GITREMOTE-HELPERS(1)

Pages that refer to this page: git-remote-testgit(1)