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Diffstat (limited to 'Documentation/git-remote-helpers.txt')
| -rw-r--r-- | Documentation/git-remote-helpers.txt | 287 |
1 files changed, 228 insertions, 59 deletions
diff --git a/Documentation/git-remote-helpers.txt b/Documentation/git-remote-helpers.txt index 1b5f61a..f5836e4 100644 --- a/Documentation/git-remote-helpers.txt +++ b/Documentation/git-remote-helpers.txt @@ -3,20 +3,192 @@ git-remote-helpers(1) NAME ---- -git-remote-helpers - Helper programs for interoperation with remote git +git-remote-helpers - Helper programs to interact with remote repositories SYNOPSIS -------- -'git remote-<transport>' <remote> +[verse] +'git remote-<transport>' <repository> [<URL>] DESCRIPTION ----------- -These programs are normally not used directly by end users, but are -invoked by various git programs that interact with remote repositories -when the repository they would operate on will be accessed using -transport code not linked into the main git binary. Various particular -helper programs will behave as documented here. +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 +uses to determine what other commands the helper will accept. Those +other commands can be used to discover and update remote refs, +transport objects between the object database and the remote repository, +and update the local object store. + +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'. + +INPUT FORMAT +------------ + +Git sends the remote helper a list of commands on standard input, one +per line. The first command is always the 'capabilities' command, in +response to which the remote helper must print a list of the +capabilities it supports (see below) followed by a blank line. The +response to the capabilities command determines what commands Git uses +in the remainder of the command stream. + +The command stream is terminated by a blank line. In some cases +(indicated in the documentation of the relevant commands), this blank +line is followed by a payload in some other protocol (e.g., the pack +protocol), while in others it indicates the end of input. + +Capabilities +~~~~~~~~~~~~ + +Each remote helper is expected to support only a subset of commands. +The operations a helper supports are declared to git in the response +to the `capabilities` command (see COMMANDS, below). + +'option':: + For specifying settings like `verbosity` (how much output to + write to stderr) and `depth` (how much history is wanted in the + case of a shallow clone) that affect how other commands are + carried out. + +'connect':: + For fetching and pushing using git's native packfile protocol + that requires a bidirectional, full-duplex connection. + +'push':: + For listing remote refs and pushing specified objects from the + local object store to remote refs. + +'fetch':: + For listing remote refs and fetching the associated history to + the local object store. + +'import':: + For listing remote refs and fetching the associated history as + a fast-import stream. + +'refspec' <refspec>:: + This modifies the 'import' capability, allowing the produced + fast-import stream to modify refs in a private namespace + instead of writing to refs/heads or refs/remotes directly. + It is recommended that all importers providing the 'import' + capability use this. ++ +A helper advertising the capability +`refspec refs/heads/*:refs/svn/origin/branches/*` +is saying that, when it is asked to `import refs/heads/topic`, the +stream it outputs will update the `refs/svn/origin/branches/topic` +ref. ++ +This capability can be advertised multiple times. The first +applicable refspec takes precedence. The left-hand of refspecs +advertised with this capability must cover all refs reported by +the list command. If no 'refspec' capability is advertised, +there is an implied `refspec *:*`. + +Capabilities for Pushing +~~~~~~~~~~~~~~~~~~~~~~~~ +'connect':: + Can attempt to connect to 'git receive-pack' (for pushing), + 'git upload-pack', etc for communication using the + packfile protocol. ++ +Supported commands: 'connect'. + +'push':: + Can discover remote refs and push local commits and the + history leading up to them to new or existing remote refs. ++ +Supported commands: 'list for-push', 'push'. + +If a helper advertises both 'connect' and 'push', git will use +'connect' if possible and fall back to 'push' if the helper requests +so when connecting (see the 'connect' command under COMMANDS). + +Capabilities for Fetching +~~~~~~~~~~~~~~~~~~~~~~~~~ +'connect':: + Can try to connect to 'git upload-pack' (for fetching), + 'git receive-pack', etc for communication using the + packfile protocol. ++ +Supported commands: 'connect'. + +'fetch':: + Can discover remote refs and transfer objects reachable from + them to the local object store. ++ +Supported commands: 'list', 'fetch'. + +'import':: + Can discover remote refs and output objects reachable from + them as a stream in fast-import format. ++ +Supported commands: 'list', 'import'. + +If a helper advertises 'connect', git will use it if possible and +fall back to another capability if the helper requests so when +connecting (see the 'connect' command under COMMANDS). +When choosing between 'fetch' and 'import', git prefers 'fetch'. +Other frontends may have some other order of preference. + +'refspec' <refspec>:: + This modifies the 'import' capability. ++ +A helper advertising +`refspec refs/heads/*:refs/svn/origin/branches/*` +in its capabilities is saying that, when it handles +`import refs/heads/topic`, the stream it outputs will update the +`refs/svn/origin/branches/topic` ref. ++ +This capability can be advertised multiple times. The first +applicable refspec takes precedence. The left-hand of refspecs +advertised with this capability must cover all refs reported by +the list command. If no 'refspec' capability is advertised, +there is an implied `refspec *:*`. + +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. +The 'GIT_DIR' environment variable is set up for the remote helper +and can be used to determine where to store additional data or from +which directory to invoke auxiliary git commands. + +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 -------- @@ -25,8 +197,8 @@ 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 '*'. - This marks them mandatory for git version using the remote + 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). @@ -35,27 +207,27 @@ Commands are given by the caller on the helper's standard input, one per line. [<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. After the - complete list, outputs a blank line. + 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>:: - Set the transport helper option <name> to <value>. Outputs a + 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 correct + (option <name> is supported but <value> is not valid for it). Options should be set before other commands, - and may how those commands behave. + 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, and the batch is terminated with a blank line. + 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. @@ -67,9 +239,24 @@ suitably updated. Supported if the helper has the "fetch" capability. 'push' +<src>:<dst>:: - Pushes the given <src> commit or branch locally to the + 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. + one or more 'push' commands is terminated with a blank line + (if there is only one reference to push, a single 'push' command + is followed by a blank line). For example, the following would + be two batches of 'push', the first asking the remote-helper + to push the local ref 'master' to the remote ref 'master' and + the local 'HEAD' to the remote 'branch', and the second + asking to push ref 'foo' to ref 'bar' (forced update requested + by the '+'). ++ +------------ +push refs/heads/master:refs/heads/master +push HEAD:refs/heads/branch +\n +push +refs/heads/foo:refs/heads/bar +\n +------------ + Zero or more protocol options may be entered after the last 'push' command, before the batch's terminating blank line. @@ -91,6 +278,14 @@ Supported if the helper has the "push" capability. by applying the refspecs from the "refspec" capability to the name of the ref. + +Especially useful for interoperability with a foreign versioning +system. ++ +Just like 'push', a batch sequence of one or more 'import' is +terminated with a blank line. For each batch of 'import', the remote +helper should produce a fast-import stream terminated by a 'done' +command. ++ Supported if the helper has the "import" capability. 'connect' <service>:: @@ -115,34 +310,6 @@ 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':: - This helper supports the 'fetch' command. - -'option':: - This helper supports the option command. - -'push':: - This helper supports the 'push' command. - -'import':: - This helper supports the 'import' command. - -'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 "*:*" - -'connect':: - This helper supports the 'connect' command. - REF LIST ATTRIBUTES ------------------- @@ -157,20 +324,20 @@ REF LIST ATTRIBUTES OPTIONS ------- -'option verbosity' <N>:: - Change the level of messages displayed by the helper. - When N is 0 the end-user has asked the process to be - quiet, and the helper should produce only error output. - N of 1 is the default level of verbosity, higher values - of N correspond to the number of -v flags passed on the +'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'\}:: - Enable (or disable) progress messages displayed by the + Enables (or disables) progress messages displayed by the transport helper during a command. 'option depth' <depth>:: - Deepen the history of a shallow repository. + Deepens the history of a shallow repository. 'option followtags' \{'true'|'false'\}:: If enabled the helper should automatically fetch annotated @@ -186,14 +353,16 @@ OPTIONS helpers this only applies to the 'push', if supported. 'option servpath <c-style-quoted-path>':: - Set service path (--upload-pack, --receive-pack etc.) for - next connect. Remote helper MAY support this option. Remote - helper MUST NOT rely on this option being set before + 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. -Documentation -------------- -Documentation by Daniel Barkalow and Ilari Liusvaara +SEE ALSO +-------- +linkgit:git-remote[1] + +linkgit:git-remote-testgit[1] GIT --- |