Documentation/git-remote-helpers.txt

   1 git-remote-helpers(1)
   2 =====================
   3
   4 NAME
   5 ----
   6 git-remote-helpers - Helper programs to interact with remote repositories
   7
   8 SYNOPSIS
   9 --------
  10 'git remote-<transport>' <repository> [<URL>]
  11
  12 DESCRIPTION
  13 -----------
  14
  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.
  25
  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.
  31
  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.
  36
  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'.
  41
  42 INVOCATION
  43 ----------
  44
  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
  51 When git encounters a URL of the form '<transport>://<address>', where
  52 '<transport>' is a protocol that it cannot handle natively, it
  53 automatically invokes 'git remote-<transport>' with the full URL as
  54 the second argument. If such a URL is encountered directly on the
  55 command line, the first argument is the same as the second, and if it
  56 is encountered in a configured remote, the first argument is the name
  57 of that remote.
  58
  59 A URL of the form '<transport>::<address>' explicitly instructs git to
  60 invoke 'git remote-<transport>' with '<address>' as the second
  61 argument. If such a URL is encountered directly on the command line,
  62 the first argument is '<address>', and if it is encountered in a
  63 configured remote, the first argument is the name of that remote.
  64
  65 Additionally, when a configured remote has 'remote.<name>.vcs' set to
  66 '<transport>', git explicitly invokes 'git remote-<transport>' with
  67 '<name>' as the first argument. If set, the second argument is
  68 'remote.<name>.url'; otherwise, the second argument is omitted.
  69
  70 COMMANDS
  71 --------
  72
  73 Commands are given by the caller on the helper's standard input, one per line.
  74
  75 'capabilities'::
  76         Lists the capabilities of the helper, one per line, ending
  77         with a blank line. Each capability may be preceded with '*',
  78         which marks them mandatory for git version using the remote
  79         helper to understand (unknown mandatory capability is fatal
  80         error).
  81
  82 'list'::
  83         Lists the refs, one per line, in the format "<value> <name>
  84         [<attr> ...]". The value may be a hex sha1 hash, "@<dest>" for
  85         a symref, or "?" to indicate that the helper could not get the
  86         value of the ref. A space-separated list of attributes follows
  87         the name; unrecognized attributes are ignored. The list ends
  88         with a blank line.
  89 +
  90 If 'push' is supported this may be called as 'list for-push'
  91 to obtain the current refs prior to sending one or more 'push'
  92 commands to the helper.
  93
  94 'option' <name> <value>::
  95         Sets the transport helper option <name> to <value>.  Outputs a
  96         single line containing one of 'ok' (option successfully set),
  97         'unsupported' (option not recognized) or 'error <msg>'
  98         (option <name> is supported but <value> is not valid
  99         for it).  Options should be set before other commands,
 100         and may influence the behavior of those commands.
 101 +
 102 Supported if the helper has the "option" capability.
 103
 104 'fetch' <sha1> <name>::
 105         Fetches the given object, writing the necessary objects
 106         to the database.  Fetch commands are sent in a batch, one
 107         per line, terminated with a blank line.
 108         Outputs a single blank line when all fetch commands in the
 109         same batch are complete. Only objects which were reported
 110         in the ref list with a sha1 may be fetched this way.
 111 +
 112 Optionally may output a 'lock <file>' line indicating a file under
 113 GIT_DIR/objects/pack which is keeping a pack until refs can be
 114 suitably updated.
 115 +
 116 Supported if the helper has the "fetch" capability.
 117
 118 'push' +<src>:<dst>::
 119         Pushes the given local <src> commit or branch to the
 120         remote branch described by <dst>.  A batch sequence of
 121         one or more push commands is terminated with a blank line.
 122 +
 123 Zero or more protocol options may be entered after the last 'push'
 124 command, before the batch's terminating blank line.
 125 +
 126 When the push is complete, outputs one or more 'ok <dst>' or
 127 'error <dst> <why>?' lines to indicate success or failure of
 128 each pushed ref.  The status report output is terminated by
 129 a blank line.  The option field <why> may be quoted in a C
 130 style string if it contains an LF.
 131 +
 132 Supported if the helper has the "push" capability.
 133
 134 'import' <name>::
 135         Produces a fast-import stream which imports the current value
 136         of the named ref. It may additionally import other refs as
 137         needed to construct the history efficiently. The script writes
 138         to a helper-specific private namespace. The value of the named
 139         ref should be written to a location in this namespace derived
 140         by applying the refspecs from the "refspec" capability to the
 141         name of the ref.
 142 +
 143 Especially useful for interoperability with a foreign versioning
 144 system.
 145 +
 146 Supported if the helper has the "import" capability.
 147
 148 'connect' <service>::
 149         Connects to given service. Standard input and standard output
 150         of helper are connected to specified service (git prefix is
 151         included in service name so e.g. fetching uses 'git-upload-pack'
 152         as service) on remote side. Valid replies to this command are
 153         empty line (connection established), 'fallback' (no smart
 154         transport support, fall back to dumb transports) and just
 155         exiting with error message printed (can't connect, don't
 156         bother trying to fall back). After line feed terminating the
 157         positive (empty) response, the output of service starts. After
 158         the connection ends, the remote helper exits.
 159 +
 160 Supported if the helper has the "connect" capability.
 161
 162 If a fatal error occurs, the program writes the error message to
 163 stderr and exits. The caller should expect that a suitable error
 164 message has been printed if the child closes the connection without
 165 completing a valid response for the current command.
 166
 167 Additional commands may be supported, as may be determined from
 168 capabilities reported by the helper.
 169
 170 CAPABILITIES
 171 ------------
 172
 173 'fetch'::
 174 'option'::
 175 'push'::
 176 'import'::
 177 'connect'::
 178         This helper supports the corresponding command with the same name.
 179
 180 'refspec' 'spec'::
 181         When using the import command, expect the source ref to have
 182         been written to the destination ref. The earliest applicable
 183         refspec takes precedence. For example
 184         "refs/heads/*:refs/svn/origin/branches/*" means that, after an
 185         "import refs/heads/name", the script has written to
 186         refs/svn/origin/branches/name. If this capability is used at
 187         all, it must cover all refs reported by the list command; if
 188         it is not used, it is effectively "*:*"
 189
 190 REF LIST ATTRIBUTES
 191 -------------------
 192
 193 'for-push'::
 194         The caller wants to use the ref list to prepare push
 195         commands.  A helper might chose to acquire the ref list by
 196         opening a different type of connection to the destination.
 197
 198 'unchanged'::
 199         This ref is unchanged since the last import or fetch, although
 200         the helper cannot necessarily determine what value that produced.
 201
 202 OPTIONS
 203 -------
 204 'option verbosity' <n>::
 205         Changes the verbosity of messages displayed by the helper.
 206         A value of 0 for <n> means that processes operate
 207         quietly, and the helper produces only error output.
 208         1 is the default level of verbosity, and higher values
 209         of <n> correspond to the number of -v flags passed on the
 210         command line.
 211
 212 'option progress' \{'true'|'false'\}::
 213         Enables (or disables) progress messages displayed by the
 214         transport helper during a command.
 215
 216 'option depth' <depth>::
 217         Deepens the history of a shallow repository.
 218
 219 'option followtags' \{'true'|'false'\}::
 220         If enabled the helper should automatically fetch annotated
 221         tag objects if the object the tag points at was transferred
 222         during the fetch command.  If the tag is not fetched by
 223         the helper a second fetch command will usually be sent to
 224         ask for the tag specifically.  Some helpers may be able to
 225         use this option to avoid a second network connection.
 226
 227 'option dry-run' \{'true'|'false'\}:
 228         If true, pretend the operation completed successfully,
 229         but don't actually change any repository data.  For most
 230         helpers this only applies to the 'push', if supported.
 231
 232 'option servpath <c-style-quoted-path>'::
 233         Sets service path (--upload-pack, --receive-pack etc.) for
 234         next connect. Remote helper may support this option, but
 235         must not rely on this option being set before
 236         connect request occurs.
 237
 238 SEE ALSO
 239 --------
 240 linkgit:git-remote[1]
 241
 242 GIT
 243 ---
 244 Part of the linkgit:git[1] suite