1 git-remote-helpers(1)
2 =====================
4 NAME
5 ----
6 git-remote-helpers - Helper programs to interact with remote repositories
8 SYNOPSIS
9 --------
10 'git remote-<transport>' <repository> [<URL>]
12 DESCRIPTION
13 -----------
15 Remote helper programs are normally not used directly by end users,
16 but they are invoked by git when it needs to interact with remote
17 repositories git does not support natively. A given helper will
18 implement a subset of the capabilities documented here. When git
19 needs to interact with a repository using a remote helper, it spawns
20 the helper as an independent process, sends commands to the helper's
21 standard input, and expects results from the helper's standard
22 output. Because a remote helper runs as an independent process from
23 git, there is no need to re-link git to add a new helper, nor any
24 need to link the helper with the implementation of git.
26 Every helper must support the "capabilities" command, which git will
27 use to determine what other commands the helper will accept. Other
28 commands generally concern facilities like discovering and updating
29 remote refs, transporting objects between the object database and
30 the remote repository, and updating the local object store.
32 Helpers supporting the 'fetch' capability can discover refs from the
33 remote repository and transfer objects reachable from those refs to
34 the local object store. Helpers supporting the 'push' capability can
35 transfer local objects to the remote repository and update remote refs.
37 Git comes with a "curl" family of remote helpers, that handle various
38 transport protocols, such as 'git-remote-http', 'git-remote-https',
39 'git-remote-ftp' and 'git-remote-ftps'. They implement the capabilities
40 'fetch', 'option', and 'push'.
42 INVOCATION
43 ----------
45 Remote helper programs are invoked with one or (optionally) two
46 arguments. The first argument specifies a remote repository as in git;
47 it is either the name of a configured remote or a URL. The second
48 argument specifies a URL; it is usually of the form
49 '<transport>://<address>', but any arbitrary string is possible.
50 The 'GIT_DIR' environment variable is set up for the remote helper
51 and can be used to determine where to store additional data or from
52 which directory to invoke auxiliary git commands.
54 When git encounters a URL of the form '<transport>://<address>', where
55 '<transport>' is a protocol that it cannot handle natively, it
56 automatically invokes 'git remote-<transport>' with the full URL as
57 the second argument. If such a URL is encountered directly on the
58 command line, the first argument is the same as the second, and if it
59 is encountered in a configured remote, the first argument is the name
60 of that remote.
62 A URL of the form '<transport>::<address>' explicitly instructs git to
63 invoke 'git remote-<transport>' with '<address>' as the second
64 argument. If such a URL is encountered directly on the command line,
65 the first argument is '<address>', and if it is encountered in a
66 configured remote, the first argument is the name of that remote.
68 Additionally, when a configured remote has 'remote.<name>.vcs' set to
69 '<transport>', git explicitly invokes 'git remote-<transport>' with
70 '<name>' as the first argument. If set, the second argument is
71 'remote.<name>.url'; otherwise, the second argument is omitted.
73 COMMANDS
74 --------
76 Commands are given by the caller on the helper's standard input, one per line.
78 'capabilities'::
79 Lists the capabilities of the helper, one per line, ending
80 with a blank line. Each capability may be preceded with '*',
81 which marks them mandatory for git version using the remote
82 helper to understand (unknown mandatory capability is fatal
83 error).
85 'list'::
86 Lists the refs, one per line, in the format "<value> <name>
87 [<attr> ...]". The value may be a hex sha1 hash, "@<dest>" for
88 a symref, or "?" to indicate that the helper could not get the
89 value of the ref. A space-separated list of attributes follows
90 the name; unrecognized attributes are ignored. The list ends
91 with a blank line.
92 +
93 If 'push' is supported this may be called as 'list for-push'
94 to obtain the current refs prior to sending one or more 'push'
95 commands to the helper.
97 'option' <name> <value>::
98 Sets the transport helper option <name> to <value>. Outputs a
99 single line containing one of 'ok' (option successfully set),
100 'unsupported' (option not recognized) or 'error <msg>'
101 (option <name> is supported but <value> is not valid
102 for it). Options should be set before other commands,
103 and may influence the behavior of those commands.
104 +
105 Supported if the helper has the "option" capability.
107 'fetch' <sha1> <name>::
108 Fetches the given object, writing the necessary objects
109 to the database. Fetch commands are sent in a batch, one
110 per line, terminated with a blank line.
111 Outputs a single blank line when all fetch commands in the
112 same batch are complete. Only objects which were reported
113 in the ref list with a sha1 may be fetched this way.
114 +
115 Optionally may output a 'lock <file>' line indicating a file under
116 GIT_DIR/objects/pack which is keeping a pack until refs can be
117 suitably updated.
118 +
119 Supported if the helper has the "fetch" capability.
121 'push' +<src>:<dst>::
122 Pushes the given local <src> commit or branch to the
123 remote branch described by <dst>. A batch sequence of
124 one or more push commands is terminated with a blank line.
125 +
126 Zero or more protocol options may be entered after the last 'push'
127 command, before the batch's terminating blank line.
128 +
129 When the push is complete, outputs one or more 'ok <dst>' or
130 'error <dst> <why>?' lines to indicate success or failure of
131 each pushed ref. The status report output is terminated by
132 a blank line. The option field <why> may be quoted in a C
133 style string if it contains an LF.
134 +
135 Supported if the helper has the "push" capability.
137 'import' <name>::
138 Produces a fast-import stream which imports the current value
139 of the named ref. It may additionally import other refs as
140 needed to construct the history efficiently. The script writes
141 to a helper-specific private namespace. The value of the named
142 ref should be written to a location in this namespace derived
143 by applying the refspecs from the "refspec" capability to the
144 name of the ref.
145 +
146 Especially useful for interoperability with a foreign versioning
147 system.
148 +
149 Supported if the helper has the "import" capability.
151 'connect' <service>::
152 Connects to given service. Standard input and standard output
153 of helper are connected to specified service (git prefix is
154 included in service name so e.g. fetching uses 'git-upload-pack'
155 as service) on remote side. Valid replies to this command are
156 empty line (connection established), 'fallback' (no smart
157 transport support, fall back to dumb transports) and just
158 exiting with error message printed (can't connect, don't
159 bother trying to fall back). After line feed terminating the
160 positive (empty) response, the output of service starts. After
161 the connection ends, the remote helper exits.
162 +
163 Supported if the helper has the "connect" capability.
165 If a fatal error occurs, the program writes the error message to
166 stderr and exits. The caller should expect that a suitable error
167 message has been printed if the child closes the connection without
168 completing a valid response for the current command.
170 Additional commands may be supported, as may be determined from
171 capabilities reported by the helper.
173 CAPABILITIES
174 ------------
176 'fetch'::
177 'option'::
178 'push'::
179 'import'::
180 'connect'::
181 This helper supports the corresponding command with the same name.
183 'refspec' 'spec'::
184 When using the import command, expect the source ref to have
185 been written to the destination ref. The earliest applicable
186 refspec takes precedence. For example
187 "refs/heads/{asterisk}:refs/svn/origin/branches/{asterisk}" means
188 that, after an "import refs/heads/name", the script has written to
189 refs/svn/origin/branches/name. If this capability is used at
190 all, it must cover all refs reported by the list command; if
191 it is not used, it is effectively "{asterisk}:{asterisk}"
193 REF LIST ATTRIBUTES
194 -------------------
196 'for-push'::
197 The caller wants to use the ref list to prepare push
198 commands. A helper might chose to acquire the ref list by
199 opening a different type of connection to the destination.
201 'unchanged'::
202 This ref is unchanged since the last import or fetch, although
203 the helper cannot necessarily determine what value that produced.
205 OPTIONS
206 -------
207 'option verbosity' <n>::
208 Changes the verbosity of messages displayed by the helper.
209 A value of 0 for <n> means that processes operate
210 quietly, and the helper produces only error output.
211 1 is the default level of verbosity, and higher values
212 of <n> correspond to the number of -v flags passed on the
213 command line.
215 'option progress' \{'true'|'false'\}::
216 Enables (or disables) progress messages displayed by the
217 transport helper during a command.
219 'option depth' <depth>::
220 Deepens the history of a shallow repository.
222 'option followtags' \{'true'|'false'\}::
223 If enabled the helper should automatically fetch annotated
224 tag objects if the object the tag points at was transferred
225 during the fetch command. If the tag is not fetched by
226 the helper a second fetch command will usually be sent to
227 ask for the tag specifically. Some helpers may be able to
228 use this option to avoid a second network connection.
230 'option dry-run' \{'true'|'false'\}:
231 If true, pretend the operation completed successfully,
232 but don't actually change any repository data. For most
233 helpers this only applies to the 'push', if supported.
235 'option servpath <c-style-quoted-path>'::
236 Sets service path (--upload-pack, --receive-pack etc.) for
237 next connect. Remote helper may support this option, but
238 must not rely on this option being set before
239 connect request occurs.
241 SEE ALSO
242 --------
243 linkgit:git-remote[1]
245 GIT
246 ---
247 Part of the linkgit:git[1] suite