6 gitremote-helpers - Helper programs to interact with remote repositories
11 'git remote-<transport>' <repository> [<URL>]
16 Remote helper programs are normally not used directly by end users,
17 but they are invoked by Git when it needs to interact with remote
18 repositories Git does not support natively. A given helper will
19 implement a subset of the capabilities documented here. When Git
20 needs to interact with a repository using a remote helper, it spawns
21 the helper as an independent process, sends commands to the helper's
22 standard input, and expects results from the helper's standard
23 output. Because a remote helper runs as an independent process from
24 Git, there is no need to re-link Git to add a new helper, nor any
25 need to link the helper with the implementation of Git.
27 Every helper must support the "capabilities" command, which Git
28 uses to determine what other commands the helper will accept. Those
29 other commands can be used to discover and update remote refs,
30 transport objects between the object database and the remote repository,
31 and update the local object store.
33 Git comes with a "curl" family of remote helpers, that handle various
34 transport protocols, such as 'git-remote-http', 'git-remote-https',
35 'git-remote-ftp' and 'git-remote-ftps'. They implement the capabilities
36 'fetch', 'option', and 'push'.
41 Remote helper programs are invoked with one or (optionally) two
42 arguments. The first argument specifies a remote repository as in Git;
43 it is either the name of a configured remote or a URL. The second
44 argument specifies a URL; it is usually of the form
45 '<transport>://<address>', but any arbitrary string is possible.
46 The 'GIT_DIR' environment variable is set up for the remote helper
47 and can be used to determine where to store additional data or from
48 which directory to invoke auxiliary Git commands.
50 When Git encounters a URL of the form '<transport>://<address>', where
51 '<transport>' is a protocol that it cannot handle natively, it
52 automatically invokes 'git remote-<transport>' with the full URL as
53 the second argument. If such a URL is encountered directly on the
54 command line, the first argument is the same as the second, and if it
55 is encountered in a configured remote, the first argument is the name
58 A URL of the form '<transport>::<address>' explicitly instructs Git to
59 invoke 'git remote-<transport>' with '<address>' as the second
60 argument. If such a URL is encountered directly on the command line,
61 the first argument is '<address>', and if it is encountered in a
62 configured remote, the first argument is the name of that remote.
64 Additionally, when a configured remote has 'remote.<name>.vcs' set to
65 '<transport>', Git explicitly invokes 'git remote-<transport>' with
66 '<name>' as the first argument. If set, the second argument is
67 'remote.<name>.url'; otherwise, the second argument is omitted.
72 Git sends the remote helper a list of commands on standard input, one
73 per line. The first command is always the 'capabilities' command, in
74 response to which the remote helper must print a list of the
75 capabilities it supports (see below) followed by a blank line. The
76 response to the capabilities command determines what commands Git uses
77 in the remainder of the command stream.
79 The command stream is terminated by a blank line. In some cases
80 (indicated in the documentation of the relevant commands), this blank
81 line is followed by a payload in some other protocol (e.g., the pack
82 protocol), while in others it indicates the end of input.
87 Each remote helper is expected to support only a subset of commands.
88 The operations a helper supports are declared to Git in the response
89 to the `capabilities` command (see COMMANDS, below).
91 In the following, we list all defined capabilities and for
92 each we list which commands a helper with that capability
95 Capabilities for Pushing
96 ^^^^^^^^^^^^^^^^^^^^^^^^
98 Can attempt to connect to 'git receive-pack' (for pushing),
99 'git upload-pack', etc for communication using
100 git's native packfile protocol. This
101 requires a bidirectional, full-duplex connection.
103 Supported commands: 'connect'.
106 Can discover remote refs and push local commits and the
107 history leading up to them to new or existing remote refs.
109 Supported commands: 'list for-push', 'push'.
112 Can discover remote refs and push specified objects from a
113 fast-import stream to remote refs.
115 Supported commands: 'list for-push', 'export'.
117 If a helper advertises 'connect', Git will use it if possible and
118 fall back to another capability if the helper requests so when
119 connecting (see the 'connect' command under COMMANDS).
120 When choosing between 'push' and 'export', Git prefers 'push'.
121 Other frontends may have some other order of preference.
123 'no-private-update'::
124 When using the 'refspec' capability, git normally updates the
125 private ref on successful push. This update is disabled when
126 the remote-helper declares the capability 'no-private-update'.
129 Capabilities for Fetching
130 ^^^^^^^^^^^^^^^^^^^^^^^^^
132 Can try to connect to 'git upload-pack' (for fetching),
133 'git receive-pack', etc for communication using the
134 Git's native packfile protocol. This
135 requires a bidirectional, full-duplex connection.
137 Supported commands: 'connect'.
140 Can discover remote refs and transfer objects reachable from
141 them to the local object store.
143 Supported commands: 'list', 'fetch'.
146 Can discover remote refs and output objects reachable from
147 them as a stream in fast-import format.
149 Supported commands: 'list', 'import'.
151 If a helper advertises 'connect', Git will use it if possible and
152 fall back to another capability if the helper requests so when
153 connecting (see the 'connect' command under COMMANDS).
154 When choosing between 'fetch' and 'import', Git prefers 'fetch'.
155 Other frontends may have some other order of preference.
157 Miscellaneous capabilities
158 ^^^^^^^^^^^^^^^^^^^^^^^^^^
161 For specifying settings like `verbosity` (how much output to
162 write to stderr) and `depth` (how much history is wanted in the
163 case of a shallow clone) that affect how other commands are
166 'refspec' <refspec>::
167 For remote helpers that implement 'import' or 'export', this capability
168 allows the refs to be constrained to a private namespace, instead of
169 writing to refs/heads or refs/remotes directly.
170 It is recommended that all importers providing the 'import'
171 capability use this. It's mandatory for 'export'.
173 A helper advertising the capability
174 `refspec refs/heads/*:refs/svn/origin/branches/*`
175 is saying that, when it is asked to `import refs/heads/topic`, the
176 stream it outputs will update the `refs/svn/origin/branches/topic`
179 This capability can be advertised multiple times. The first
180 applicable refspec takes precedence. The left-hand of refspecs
181 advertised with this capability must cover all refs reported by
182 the list command. If no 'refspec' capability is advertised,
183 there is an implied `refspec *:*`.
186 This modifies the 'import' capability.
187 The fast-import commands 'cat-blob' and 'ls' can be used by remote-helpers
188 to retrieve information about blobs and trees that already exist in
189 fast-import's memory. This requires a channel from fast-import to the
191 If it is advertised in addition to "import", Git establishes a pipe from
192 fast-import to the remote-helper's stdin.
193 It follows that Git and fast-import are both connected to the
194 remote-helper's stdin. Because Git can send multiple commands to
195 the remote-helper it is required that helpers that use 'bidi-import'
196 buffer all 'import' commands of a batch before sending data to fast-import.
197 This is to prevent mixing commands and fast-import responses on the
200 'export-marks' <file>::
201 This modifies the 'export' capability, instructing Git to dump the
202 internal marks table to <file> when complete. For details,
203 read up on '--export-marks=<file>' in linkgit:git-fast-export[1].
205 'import-marks' <file>::
206 This modifies the 'export' capability, instructing Git to load the
207 marks specified in <file> before processing any input. For details,
208 read up on '--import-marks=<file>' in linkgit:git-fast-export[1].
211 This modifies the 'export' capability, instructing Git to pass
212 '--signed-tags=verbatim' to linkgit:git-fast-export[1]. In the
213 absence of this capability, Git will use '--signed-tags=warn-strip'.
220 Commands are given by the caller on the helper's standard input, one per line.
223 Lists the capabilities of the helper, one per line, ending
224 with a blank line. Each capability may be preceded with '*',
225 which marks them mandatory for Git versions using the remote
226 helper to understand. Any unknown mandatory capability is a
229 Support for this command is mandatory.
232 Lists the refs, one per line, in the format "<value> <name>
233 [<attr> ...]". The value may be a hex sha1 hash, "@<dest>" for
234 a symref, or "?" to indicate that the helper could not get the
235 value of the ref. A space-separated list of attributes follows
236 the name; unrecognized attributes are ignored. The list ends
239 See REF LIST ATTRIBUTES for a list of currently defined attributes.
241 Supported if the helper has the "fetch" or "import" capability.
244 Similar to 'list', except that it is used if and only if
245 the caller wants to the resulting ref list to prepare
247 A helper supporting both push and fetch can use this
248 to distinguish for which operation the output of 'list'
249 is going to be used, possibly reducing the amount
250 of work that needs to be performed.
252 Supported if the helper has the "push" or "export" capability.
254 'option' <name> <value>::
255 Sets the transport helper option <name> to <value>. Outputs a
256 single line containing one of 'ok' (option successfully set),
257 'unsupported' (option not recognized) or 'error <msg>'
258 (option <name> is supported but <value> is not valid
259 for it). Options should be set before other commands,
260 and may influence the behavior of those commands.
262 See OPTIONS for a list of currently defined options.
264 Supported if the helper has the "option" capability.
266 'fetch' <sha1> <name>::
267 Fetches the given object, writing the necessary objects
268 to the database. Fetch commands are sent in a batch, one
269 per line, terminated with a blank line.
270 Outputs a single blank line when all fetch commands in the
271 same batch are complete. Only objects which were reported
272 in the output of 'list' with a sha1 may be fetched this way.
274 Optionally may output a 'lock <file>' line indicating a file under
275 GIT_DIR/objects/pack which is keeping a pack until refs can be
278 Supported if the helper has the "fetch" capability.
280 'push' +<src>:<dst>::
281 Pushes the given local <src> commit or branch to the
282 remote branch described by <dst>. A batch sequence of
283 one or more 'push' commands is terminated with a blank line
284 (if there is only one reference to push, a single 'push' command
285 is followed by a blank line). For example, the following would
286 be two batches of 'push', the first asking the remote-helper
287 to push the local ref 'master' to the remote ref 'master' and
288 the local 'HEAD' to the remote 'branch', and the second
289 asking to push ref 'foo' to ref 'bar' (forced update requested
293 push refs/heads/master:refs/heads/master
294 push HEAD:refs/heads/branch
296 push +refs/heads/foo:refs/heads/bar
300 Zero or more protocol options may be entered after the last 'push'
301 command, before the batch's terminating blank line.
303 When the push is complete, outputs one or more 'ok <dst>' or
304 'error <dst> <why>?' lines to indicate success or failure of
305 each pushed ref. The status report output is terminated by
306 a blank line. The option field <why> may be quoted in a C
307 style string if it contains an LF.
309 Supported if the helper has the "push" capability.
312 Produces a fast-import stream which imports the current value
313 of the named ref. It may additionally import other refs as
314 needed to construct the history efficiently. The script writes
315 to a helper-specific private namespace. The value of the named
316 ref should be written to a location in this namespace derived
317 by applying the refspecs from the "refspec" capability to the
320 Especially useful for interoperability with a foreign versioning
323 Just like 'push', a batch sequence of one or more 'import' is
324 terminated with a blank line. For each batch of 'import', the remote
325 helper should produce a fast-import stream terminated by a 'done'
328 Note that if the 'bidi-import' capability is used the complete batch
329 sequence has to be buffered before starting to send data to fast-import
330 to prevent mixing of commands and fast-import responses on the helper's
333 Supported if the helper has the "import" capability.
336 Instructs the remote helper that any subsequent input is
337 part of a fast-import stream (generated by 'git fast-export')
338 containing objects which should be pushed to the remote.
340 Especially useful for interoperability with a foreign versioning
343 The 'export-marks' and 'import-marks' capabilities, if specified,
344 affect this command in so far as they are passed on to 'git
345 fast-export', which then will load/store a table of marks for
346 local objects. This can be used to implement for incremental
349 Supported if the helper has the "export" capability.
351 'connect' <service>::
352 Connects to given service. Standard input and standard output
353 of helper are connected to specified service (git prefix is
354 included in service name so e.g. fetching uses 'git-upload-pack'
355 as service) on remote side. Valid replies to this command are
356 empty line (connection established), 'fallback' (no smart
357 transport support, fall back to dumb transports) and just
358 exiting with error message printed (can't connect, don't
359 bother trying to fall back). After line feed terminating the
360 positive (empty) response, the output of service starts. After
361 the connection ends, the remote helper exits.
363 Supported if the helper has the "connect" capability.
365 If a fatal error occurs, the program writes the error message to
366 stderr and exits. The caller should expect that a suitable error
367 message has been printed if the child closes the connection without
368 completing a valid response for the current command.
370 Additional commands may be supported, as may be determined from
371 capabilities reported by the helper.
376 The 'list' command produces a list of refs in which each ref
377 may be followed by a list of attributes. The following ref list
378 attributes are defined.
381 This ref is unchanged since the last import or fetch, although
382 the helper cannot necessarily determine what value that produced.
387 The following options are defined and (under suitable circumstances)
388 set by Git if the remote helper has the 'option' capability.
390 'option verbosity' <n>::
391 Changes the verbosity of messages displayed by the helper.
392 A value of 0 for <n> means that processes operate
393 quietly, and the helper produces only error output.
394 1 is the default level of verbosity, and higher values
395 of <n> correspond to the number of -v flags passed on the
398 'option progress' \{'true'|'false'\}::
399 Enables (or disables) progress messages displayed by the
400 transport helper during a command.
402 'option depth' <depth>::
403 Deepens the history of a shallow repository.
405 'option followtags' \{'true'|'false'\}::
406 If enabled the helper should automatically fetch annotated
407 tag objects if the object the tag points at was transferred
408 during the fetch command. If the tag is not fetched by
409 the helper a second fetch command will usually be sent to
410 ask for the tag specifically. Some helpers may be able to
411 use this option to avoid a second network connection.
413 'option dry-run' \{'true'|'false'\}:
414 If true, pretend the operation completed successfully,
415 but don't actually change any repository data. For most
416 helpers this only applies to the 'push', if supported.
418 'option servpath <c-style-quoted-path>'::
419 Sets service path (--upload-pack, --receive-pack etc.) for
420 next connect. Remote helper may support this option, but
421 must not rely on this option being set before
422 connect request occurs.
426 linkgit:git-remote[1]
428 linkgit:git-remote-testgit[1]
432 Part of the linkgit:git[1] suite