6 git-remote-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 If a helper advertises 'connect', git will use it if possible and
147 fall back to another capability if the helper requests so when
148 connecting (see the 'connect' command under COMMANDS).
149 When choosing between 'fetch' and 'import', git prefers 'fetch'.
150 Other frontends may have some other order of preference.
152 Miscellaneous capabilities
153 ^^^^^^^^^^^^^^^^^^^^^^^^^^
156 For specifying settings like `verbosity` (how much output to
157 write to stderr) and `depth` (how much history is wanted in the
158 case of a shallow clone) that affect how other commands are
161 'refspec' <refspec>::
162 This modifies the 'import' capability, allowing the produced
163 fast-import stream to modify refs in a private namespace
164 instead of writing to refs/heads or refs/remotes directly.
165 It is recommended that all importers providing the 'import'
168 A helper advertising the capability
169 `refspec refs/heads/*:refs/svn/origin/branches/*`
170 is saying that, when it is asked to `import refs/heads/topic`, the
171 stream it outputs will update the `refs/svn/origin/branches/topic`
174 This capability can be advertised multiple times. The first
175 applicable refspec takes precedence. The left-hand of refspecs
176 advertised with this capability must cover all refs reported by
177 the list command. If no 'refspec' capability is advertised,
178 there is an implied `refspec *:*`.
181 This modifies the 'import' capability.
182 The fast-import commands 'cat-blob' and 'ls' can be used by remote-helpers
183 to retrieve information about blobs and trees that already exist in
184 fast-import's memory. This requires a channel from fast-import to the
186 If it is advertised in addition to "import", git establishes a pipe from
187 fast-import to the remote-helper's stdin.
188 It follows that git and fast-import are both connected to the
189 remote-helper's stdin. Because git can send multiple commands to
190 the remote-helper it is required that helpers that use 'bidi-import'
191 buffer all 'import' commands of a batch before sending data to fast-import.
192 This is to prevent mixing commands and fast-import responses on the
195 'export-marks' <file>::
196 This modifies the 'export' capability, instructing git to dump the
197 internal marks table to <file> when complete. For details,
198 read up on '--export-marks=<file>' in linkgit:git-fast-export[1].
200 'import-marks' <file>::
201 This modifies the 'export' capability, instructing git to load the
202 marks specified in <file> before processing any input. For details,
203 read up on '--import-marks=<file>' in linkgit:git-fast-export[1].
211 Commands are given by the caller on the helper's standard input, one per line.
214 Lists the capabilities of the helper, one per line, ending
215 with a blank line. Each capability may be preceded with '*',
216 which marks them mandatory for git versions using the remote
217 helper to understand. Any unknown mandatory capability is a
221 Lists the refs, one per line, in the format "<value> <name>
222 [<attr> ...]". The value may be a hex sha1 hash, "@<dest>" for
223 a symref, or "?" to indicate that the helper could not get the
224 value of the ref. A space-separated list of attributes follows
225 the name; unrecognized attributes are ignored. The list ends
228 If 'push' is supported this may be called as 'list for-push'
229 to obtain the current refs prior to sending one or more 'push'
230 commands to the helper.
232 'option' <name> <value>::
233 Sets the transport helper option <name> to <value>. Outputs a
234 single line containing one of 'ok' (option successfully set),
235 'unsupported' (option not recognized) or 'error <msg>'
236 (option <name> is supported but <value> is not valid
237 for it). Options should be set before other commands,
238 and may influence the behavior of those commands.
240 Supported if the helper has the "option" capability.
242 'fetch' <sha1> <name>::
243 Fetches the given object, writing the necessary objects
244 to the database. Fetch commands are sent in a batch, one
245 per line, terminated with a blank line.
246 Outputs a single blank line when all fetch commands in the
247 same batch are complete. Only objects which were reported
248 in the ref list with a sha1 may be fetched this way.
250 Optionally may output a 'lock <file>' line indicating a file under
251 GIT_DIR/objects/pack which is keeping a pack until refs can be
254 Supported if the helper has the "fetch" capability.
256 'push' +<src>:<dst>::
257 Pushes the given local <src> commit or branch to the
258 remote branch described by <dst>. A batch sequence of
259 one or more 'push' commands is terminated with a blank line
260 (if there is only one reference to push, a single 'push' command
261 is followed by a blank line). For example, the following would
262 be two batches of 'push', the first asking the remote-helper
263 to push the local ref 'master' to the remote ref 'master' and
264 the local 'HEAD' to the remote 'branch', and the second
265 asking to push ref 'foo' to ref 'bar' (forced update requested
269 push refs/heads/master:refs/heads/master
270 push HEAD:refs/heads/branch
272 push +refs/heads/foo:refs/heads/bar
276 Zero or more protocol options may be entered after the last 'push'
277 command, before the batch's terminating blank line.
279 When the push is complete, outputs one or more 'ok <dst>' or
280 'error <dst> <why>?' lines to indicate success or failure of
281 each pushed ref. The status report output is terminated by
282 a blank line. The option field <why> may be quoted in a C
283 style string if it contains an LF.
285 Supported if the helper has the "push" capability.
288 Produces a fast-import stream which imports the current value
289 of the named ref. It may additionally import other refs as
290 needed to construct the history efficiently. The script writes
291 to a helper-specific private namespace. The value of the named
292 ref should be written to a location in this namespace derived
293 by applying the refspecs from the "refspec" capability to the
296 Especially useful for interoperability with a foreign versioning
299 Just like 'push', a batch sequence of one or more 'import' is
300 terminated with a blank line. For each batch of 'import', the remote
301 helper should produce a fast-import stream terminated by a 'done'
304 Note that if the 'bidi-import' capability is used the complete batch
305 sequence has to be buffered before starting to send data to fast-import
306 to prevent mixing of commands and fast-import responses on the helper's
309 Supported if the helper has the 'import' capability.
312 Instructs the remote helper that any subsequent input is
313 part of a fast-import stream (generated by 'git fast-export')
314 containing objects which should be pushed to the remote.
316 Especially useful for interoperability with a foreign versioning
319 The 'export-marks' and 'import-marks' capabilities, if specified,
320 affect this command in so far as they are passed on to 'git
321 fast-export', which then will load/store a table of marks for
322 local objects. This can be used to implement for incremental
325 Supported if the helper has the 'export' capability.
327 'connect' <service>::
328 Connects to given service. Standard input and standard output
329 of helper are connected to specified service (git prefix is
330 included in service name so e.g. fetching uses 'git-upload-pack'
331 as service) on remote side. Valid replies to this command are
332 empty line (connection established), 'fallback' (no smart
333 transport support, fall back to dumb transports) and just
334 exiting with error message printed (can't connect, don't
335 bother trying to fall back). After line feed terminating the
336 positive (empty) response, the output of service starts. After
337 the connection ends, the remote helper exits.
339 Supported if the helper has the "connect" capability.
341 If a fatal error occurs, the program writes the error message to
342 stderr and exits. The caller should expect that a suitable error
343 message has been printed if the child closes the connection without
344 completing a valid response for the current command.
346 Additional commands may be supported, as may be determined from
347 capabilities reported by the helper.
353 The caller wants to use the ref list to prepare push
354 commands. A helper might chose to acquire the ref list by
355 opening a different type of connection to the destination.
358 This ref is unchanged since the last import or fetch, although
359 the helper cannot necessarily determine what value that produced.
363 'option verbosity' <n>::
364 Changes the verbosity of messages displayed by the helper.
365 A value of 0 for <n> means that processes operate
366 quietly, and the helper produces only error output.
367 1 is the default level of verbosity, and higher values
368 of <n> correspond to the number of -v flags passed on the
371 'option progress' \{'true'|'false'\}::
372 Enables (or disables) progress messages displayed by the
373 transport helper during a command.
375 'option depth' <depth>::
376 Deepens the history of a shallow repository.
378 'option followtags' \{'true'|'false'\}::
379 If enabled the helper should automatically fetch annotated
380 tag objects if the object the tag points at was transferred
381 during the fetch command. If the tag is not fetched by
382 the helper a second fetch command will usually be sent to
383 ask for the tag specifically. Some helpers may be able to
384 use this option to avoid a second network connection.
386 'option dry-run' \{'true'|'false'\}:
387 If true, pretend the operation completed successfully,
388 but don't actually change any repository data. For most
389 helpers this only applies to the 'push', if supported.
391 'option servpath <c-style-quoted-path>'::
392 Sets service path (--upload-pack, --receive-pack etc.) for
393 next connect. Remote helper may support this option, but
394 must not rely on this option being set before
395 connect request occurs.
399 linkgit:git-remote[1]
401 linkgit:git-remote-testgit[1]
405 Part of the linkgit:git[1] suite