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.

           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.

           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.

       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.

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
       2017-09-15.  If you discover any rendering problems in this HTML ver‐
       sion 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 man‐
       ual page), send a mail to man-pages@man7.org

Git 2.13.2.556.g5116f7           07/05/2017             GITREMOTE-HELPERS(1)

Pages that refer to this page: git-clone(1)git-fetch(1)git-pull(1)git-push(1)git-remote-ext(1)git-remote-fd(1)git-remote-testgit(1)