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.
124 Capabilities for Fetching
125 ^^^^^^^^^^^^^^^^^^^^^^^^^
127 Can try to connect to 'git upload-pack' (for fetching),
128 'git receive-pack', etc for communication using the
129 Git's native packfile protocol. This
130 requires a bidirectional, full-duplex connection.
132 Supported commands: 'connect'.
135 Can discover remote refs and transfer objects reachable from
136 them to the local object store.
138 Supported commands: 'list', 'fetch'.
141 Can discover remote refs and output objects reachable from
142 them as a stream in fast-import format.
144 Supported commands: 'list', 'import'.
146 'check-connectivity'::
147 Can guarantee that when a clone is requested, the received
148 pack is self contained and is connected.
150 If a helper advertises 'connect', Git will use it if possible and
151 fall back to another capability if the helper requests so when
152 connecting (see the 'connect' command under COMMANDS).
153 When choosing between 'fetch' and 'import', Git prefers 'fetch'.
154 Other frontends may have some other order of preference.
156 Miscellaneous capabilities
157 ^^^^^^^^^^^^^^^^^^^^^^^^^^
160 For specifying settings like `verbosity` (how much output to
161 write to stderr) and `depth` (how much history is wanted in the
162 case of a shallow clone) that affect how other commands are
165 'refspec' <refspec>::
166 For remote helpers that implement 'import' or 'export', this capability
167 allows the refs to be constrained to a private namespace, instead of
168 writing to refs/heads or refs/remotes directly.
169 It is recommended that all importers providing the 'import'
170 capability use this. It's mandatory for 'export'.
172 A helper advertising the capability
173 `refspec refs/heads/*:refs/svn/origin/branches/*`
174 is saying that, when it is asked to `import refs/heads/topic`, the
175 stream it outputs will update the `refs/svn/origin/branches/topic`
178 This capability can be advertised multiple times. The first
179 applicable refspec takes precedence. The left-hand of refspecs
180 advertised with this capability must cover all refs reported by
181 the list command. If no 'refspec' capability is advertised,
182 there is an implied `refspec *:*`.
185 This modifies the 'import' capability.
186 The fast-import commands 'cat-blob' and 'ls' can be used by remote-helpers
187 to retrieve information about blobs and trees that already exist in
188 fast-import's memory. This requires a channel from fast-import to the
190 If it is advertised in addition to "import", Git establishes a pipe from
191 fast-import to the remote-helper's stdin.
192 It follows that Git and fast-import are both connected to the
193 remote-helper's stdin. Because Git can send multiple commands to
194 the remote-helper it is required that helpers that use 'bidi-import'
195 buffer all 'import' commands of a batch before sending data to fast-import.
196 This is to prevent mixing commands and fast-import responses on the
199 'export-marks' <file>::
200 This modifies the 'export' capability, instructing Git to dump the
201 internal marks table to <file> when complete. For details,
202 read up on '--export-marks=<file>' in linkgit:git-fast-export[1].
204 'import-marks' <file>::
205 This modifies the 'export' capability, instructing Git to load the
206 marks specified in <file> before processing any input. For details,
207 read up on '--import-marks=<file>' in linkgit:git-fast-export[1].
210 This modifies the 'export' capability, instructing Git to pass
211 '--signed-tags=verbatim' to linkgit:git-fast-export[1]. In the
212 absence of this capability, Git will use '--signed-tags=warn-strip'.
219 Commands are given by the caller on the helper's standard input, one per line.
222 Lists the capabilities of the helper, one per line, ending
223 with a blank line. Each capability may be preceded with '*',
224 which marks them mandatory for Git versions using the remote
225 helper to understand. Any unknown mandatory capability is a
228 Support for this command is mandatory.
231 Lists the refs, one per line, in the format "<value> <name>
232 [<attr> ...]". The value may be a hex sha1 hash, "@<dest>" for
233 a symref, or "?" to indicate that the helper could not get the
234 value of the ref. A space-separated list of attributes follows
235 the name; unrecognized attributes are ignored. The list ends
238 See REF LIST ATTRIBUTES for a list of currently defined attributes.
240 Supported if the helper has the "fetch" or "import" capability.
243 Similar to 'list', except that it is used if and only if
244 the caller wants to the resulting ref list to prepare
246 A helper supporting both push and fetch can use this
247 to distinguish for which operation the output of 'list'
248 is going to be used, possibly reducing the amount
249 of work that needs to be performed.
251 Supported if the helper has the "push" or "export" capability.
253 'option' <name> <value>::
254 Sets the transport helper option <name> to <value>. Outputs a
255 single line containing one of 'ok' (option successfully set),
256 'unsupported' (option not recognized) or 'error <msg>'
257 (option <name> is supported but <value> is not valid
258 for it). Options should be set before other commands,
259 and may influence the behavior of those commands.
261 See OPTIONS for a list of currently defined options.
263 Supported if the helper has the "option" capability.
265 'fetch' <sha1> <name>::
266 Fetches the given object, writing the necessary objects
267 to the database. Fetch commands are sent in a batch, one
268 per line, terminated with a blank line.
269 Outputs a single blank line when all fetch commands in the
270 same batch are complete. Only objects which were reported
271 in the output of 'list' with a sha1 may be fetched this way.
273 Optionally may output a 'lock <file>' line indicating a file under
274 GIT_DIR/objects/pack which is keeping a pack until refs can be
277 If option 'check-connectivity' is requested, the helper must output
278 'connectivity-ok' if the clone is self-contained and connected.
280 Supported if the helper has the "fetch" capability.
282 'push' +<src>:<dst>::
283 Pushes the given local <src> commit or branch to the
284 remote branch described by <dst>. A batch sequence of
285 one or more 'push' commands is terminated with a blank line
286 (if there is only one reference to push, a single 'push' command
287 is followed by a blank line). For example, the following would
288 be two batches of 'push', the first asking the remote-helper
289 to push the local ref 'master' to the remote ref 'master' and
290 the local 'HEAD' to the remote 'branch', and the second
291 asking to push ref 'foo' to ref 'bar' (forced update requested
295 push refs/heads/master:refs/heads/master
296 push HEAD:refs/heads/branch
298 push +refs/heads/foo:refs/heads/bar
302 Zero or more protocol options may be entered after the last 'push'
303 command, before the batch's terminating blank line.
305 When the push is complete, outputs one or more 'ok <dst>' or
306 'error <dst> <why>?' lines to indicate success or failure of
307 each pushed ref. The status report output is terminated by
308 a blank line. The option field <why> may be quoted in a C
309 style string if it contains an LF.
311 Supported if the helper has the "push" capability.
314 Produces a fast-import stream which imports the current value
315 of the named ref. It may additionally import other refs as
316 needed to construct the history efficiently. The script writes
317 to a helper-specific private namespace. The value of the named
318 ref should be written to a location in this namespace derived
319 by applying the refspecs from the "refspec" capability to the
322 Especially useful for interoperability with a foreign versioning
325 Just like 'push', a batch sequence of one or more 'import' is
326 terminated with a blank line. For each batch of 'import', the remote
327 helper should produce a fast-import stream terminated by a 'done'
330 Note that if the 'bidi-import' capability is used the complete batch
331 sequence has to be buffered before starting to send data to fast-import
332 to prevent mixing of commands and fast-import responses on the helper's
335 Supported if the helper has the "import" capability.
338 Instructs the remote helper that any subsequent input is
339 part of a fast-import stream (generated by 'git fast-export')
340 containing objects which should be pushed to the remote.
342 Especially useful for interoperability with a foreign versioning
345 The 'export-marks' and 'import-marks' capabilities, if specified,
346 affect this command in so far as they are passed on to 'git
347 fast-export', which then will load/store a table of marks for
348 local objects. This can be used to implement for incremental
351 Supported if the helper has the "export" capability.
353 'connect' <service>::
354 Connects to given service. Standard input and standard output
355 of helper are connected to specified service (git prefix is
356 included in service name so e.g. fetching uses 'git-upload-pack'
357 as service) on remote side. Valid replies to this command are
358 empty line (connection established), 'fallback' (no smart
359 transport support, fall back to dumb transports) and just
360 exiting with error message printed (can't connect, don't
361 bother trying to fall back). After line feed terminating the
362 positive (empty) response, the output of service starts. After
363 the connection ends, the remote helper exits.
365 Supported if the helper has the "connect" capability.
367 If a fatal error occurs, the program writes the error message to
368 stderr and exits. The caller should expect that a suitable error
369 message has been printed if the child closes the connection without
370 completing a valid response for the current command.
372 Additional commands may be supported, as may be determined from
373 capabilities reported by the helper.
378 The 'list' command produces a list of refs in which each ref
379 may be followed by a list of attributes. The following ref list
380 attributes are defined.
383 This ref is unchanged since the last import or fetch, although
384 the helper cannot necessarily determine what value that produced.
389 The following options are defined and (under suitable circumstances)
390 set by Git if the remote helper has the 'option' capability.
392 'option verbosity' <n>::
393 Changes the verbosity of messages displayed by the helper.
394 A value of 0 for <n> means that processes operate
395 quietly, and the helper produces only error output.
396 1 is the default level of verbosity, and higher values
397 of <n> correspond to the number of -v flags passed on the
400 'option progress' \{'true'|'false'\}::
401 Enables (or disables) progress messages displayed by the
402 transport helper during a command.
404 'option depth' <depth>::
405 Deepens the history of a shallow repository.
407 'option followtags' \{'true'|'false'\}::
408 If enabled the helper should automatically fetch annotated
409 tag objects if the object the tag points at was transferred
410 during the fetch command. If the tag is not fetched by
411 the helper a second fetch command will usually be sent to
412 ask for the tag specifically. Some helpers may be able to
413 use this option to avoid a second network connection.
415 'option dry-run' \{'true'|'false'\}:
416 If true, pretend the operation completed successfully,
417 but don't actually change any repository data. For most
418 helpers this only applies to the 'push', if supported.
420 'option servpath <c-style-quoted-path>'::
421 Sets service path (--upload-pack, --receive-pack etc.) for
422 next connect. Remote helper may support this option, but
423 must not rely on this option being set before
424 connect request occurs.
426 'option check-connectivity' \{'true'|'false'\}::
427 Request the helper to check connectivity of a clone.
431 linkgit:git-remote[1]
433 linkgit:git-remote-testgit[1]
437 Part of the linkgit:git[1] suite