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diff --git a/Documentation/git-remote-helpers.txt b/Documentation/git-remote-helpers.txt new file mode 100644 index 0000000000..87cd11f2c4 --- /dev/null +++ b/Documentation/git-remote-helpers.txt @@ -0,0 +1,244 @@ +git-remote-helpers(1) +===================== + +NAME +---- +git-remote-helpers - Helper programs to interact with remote repositories + +SYNOPSIS +-------- +'git remote-<transport>' <repository> [<URL>] + +DESCRIPTION +----------- + +Remote helper programs are normally not used directly by end users, +but they are invoked by git when it needs to interact with remote +repositories git does not support natively. A given helper will +implement a subset of the capabilities documented here. When git +needs to interact with a repository using a remote helper, it spawns +the helper as an independent process, sends commands to the helper's +standard input, and expects results from the helper's standard +output. Because a remote helper runs as an independent process from +git, there is no need to re-link git to add a new helper, nor any +need to link the helper with the implementation of git. + +Every helper must support the "capabilities" command, which git will +use to determine what other commands the helper will accept. Other +commands generally concern facilities like discovering and updating +remote refs, transporting objects between the object database and +the remote repository, and updating the local object store. + +Helpers supporting the 'fetch' capability can discover refs from the +remote repository and transfer objects reachable from those refs to +the local object store. Helpers supporting the 'push' capability can +transfer local objects to the remote repository and update remote refs. + +Git comes with a "curl" family of remote helpers, that handle various +transport protocols, such as 'git-remote-http', 'git-remote-https', +'git-remote-ftp' and 'git-remote-ftps'. They implement the capabilities +'fetch', 'option', and 'push'. + +INVOCATION +---------- + +Remote helper programs are invoked with one or (optionally) two +arguments. The first argument specifies a remote repository as in git; +it is either the name of a configured remote or a URL. The second +argument specifies a URL; it is usually of the form +'<transport>://<address>', but any arbitrary string is possible. + +When git encounters a URL of the form '<transport>://<address>', where +'<transport>' is a protocol that it cannot handle natively, it +automatically invokes 'git remote-<transport>' with the full URL as +the second argument. If such a URL is encountered directly on the +command line, the first argument is the same as the second, and if it +is encountered in a configured remote, the first argument is the name +of that remote. + +A URL of the form '<transport>::<address>' explicitly instructs git to +invoke 'git remote-<transport>' with '<address>' as the second +argument. If such a URL is encountered directly on the command line, +the first argument is '<address>', and if it is encountered in a +configured remote, the first argument is the name of that remote. + +Additionally, when a configured remote has 'remote.<name>.vcs' set to +'<transport>', git explicitly invokes 'git remote-<transport>' with +'<name>' as the first argument. If set, the second argument is +'remote.<name>.url'; otherwise, the second argument is omitted. + +COMMANDS +-------- + +Commands are given by the caller on the helper's standard input, one per line. + +'capabilities':: + Lists the capabilities of the helper, one per line, ending + with a blank line. Each capability may be preceded with '*', + which marks them mandatory for git version using the remote + helper to understand (unknown mandatory capability is fatal + error). + +'list':: + Lists the refs, one per line, in the format "<value> <name> + [<attr> ...]". The value may be a hex sha1 hash, "@<dest>" for + a symref, or "?" to indicate that the helper could not get the + value of the ref. A space-separated list of attributes follows + the name; unrecognized attributes are ignored. The list ends + with a blank line. ++ +If 'push' is supported this may be called as 'list for-push' +to obtain the current refs prior to sending one or more 'push' +commands to the helper. + +'option' <name> <value>:: + Sets the transport helper option <name> to <value>. Outputs a + single line containing one of 'ok' (option successfully set), + 'unsupported' (option not recognized) or 'error <msg>' + (option <name> is supported but <value> is not valid + for it). Options should be set before other commands, + and may influence the behavior of those commands. ++ +Supported if the helper has the "option" capability. + +'fetch' <sha1> <name>:: + Fetches the given object, writing the necessary objects + to the database. Fetch commands are sent in a batch, one + per line, terminated with a blank line. + Outputs a single blank line when all fetch commands in the + same batch are complete. Only objects which were reported + in the ref list with a sha1 may be fetched this way. ++ +Optionally may output a 'lock <file>' line indicating a file under +GIT_DIR/objects/pack which is keeping a pack until refs can be +suitably updated. ++ +Supported if the helper has the "fetch" capability. + +'push' +<src>:<dst>:: + Pushes the given local <src> commit or branch to the + remote branch described by <dst>. A batch sequence of + one or more push commands is terminated with a blank line. ++ +Zero or more protocol options may be entered after the last 'push' +command, before the batch's terminating blank line. ++ +When the push is complete, outputs one or more 'ok <dst>' or +'error <dst> <why>?' lines to indicate success or failure of +each pushed ref. The status report output is terminated by +a blank line. The option field <why> may be quoted in a C +style string if it contains an LF. ++ +Supported if the helper has the "push" capability. + +'import' <name>:: + Produces a fast-import stream which imports the current value + of the named ref. It may additionally import other refs as + needed to construct the history efficiently. The script writes + to a helper-specific private namespace. The value of the named + ref should be written to a location in this namespace derived + by applying the refspecs from the "refspec" capability to the + name of the ref. ++ +Especially useful for interoperability with a foreign versioning +system. ++ +Supported if the helper has the "import" capability. + +'connect' <service>:: + Connects to given service. Standard input and standard output + of helper are connected to specified service (git prefix is + included in service name so e.g. fetching uses 'git-upload-pack' + as service) on remote side. Valid replies to this command are + empty line (connection established), 'fallback' (no smart + transport support, fall back to dumb transports) and just + exiting with error message printed (can't connect, don't + bother trying to fall back). After line feed terminating the + positive (empty) response, the output of service starts. After + the connection ends, the remote helper exits. ++ +Supported if the helper has the "connect" capability. + +If a fatal error occurs, the program writes the error message to +stderr and exits. The caller should expect that a suitable error +message has been printed if the child closes the connection without +completing a valid response for the current command. + +Additional commands may be supported, as may be determined from +capabilities reported by the helper. + +CAPABILITIES +------------ + +'fetch':: +'option':: +'push':: +'import':: +'connect':: + This helper supports the corresponding command with the same name. + +'refspec' 'spec':: + When using the import command, expect the source ref to have + been written to the destination ref. The earliest applicable + refspec takes precedence. For example + "refs/heads/*:refs/svn/origin/branches/*" means that, after an + "import refs/heads/name", the script has written to + refs/svn/origin/branches/name. If this capability is used at + all, it must cover all refs reported by the list command; if + it is not used, it is effectively "*:*" + +REF LIST ATTRIBUTES +------------------- + +'for-push':: + The caller wants to use the ref list to prepare push + commands. A helper might chose to acquire the ref list by + opening a different type of connection to the destination. + +'unchanged':: + This ref is unchanged since the last import or fetch, although + the helper cannot necessarily determine what value that produced. + +OPTIONS +------- +'option verbosity' <n>:: + Changes the verbosity of messages displayed by the helper. + A value of 0 for <n> means that processes operate + quietly, and the helper produces only error output. + 1 is the default level of verbosity, and higher values + of <n> correspond to the number of -v flags passed on the + command line. + +'option progress' \{'true'|'false'\}:: + Enables (or disables) progress messages displayed by the + transport helper during a command. + +'option depth' <depth>:: + Deepens the history of a shallow repository. + +'option followtags' \{'true'|'false'\}:: + If enabled the helper should automatically fetch annotated + tag objects if the object the tag points at was transferred + during the fetch command. If the tag is not fetched by + the helper a second fetch command will usually be sent to + ask for the tag specifically. Some helpers may be able to + use this option to avoid a second network connection. + +'option dry-run' \{'true'|'false'\}: + If true, pretend the operation completed successfully, + but don't actually change any repository data. For most + helpers this only applies to the 'push', if supported. + +'option servpath <c-style-quoted-path>':: + Sets service path (--upload-pack, --receive-pack etc.) for + next connect. Remote helper may support this option, but + must not rely on this option being set before + connect request occurs. + +SEE ALSO +-------- +linkgit:git-remote[1] + +GIT +--- +Part of the linkgit:git[1] suite |