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Diffstat (limited to 'Documentation/git-remote-helpers.txt')
| -rw-r--r-- | Documentation/git-remote-helpers.txt | 234 |
1 files changed, 144 insertions, 90 deletions
diff --git a/Documentation/git-remote-helpers.txt b/Documentation/git-remote-helpers.txt index f5836e46d0..6d696e0f90 100644 --- a/Documentation/git-remote-helpers.txt +++ b/Documentation/git-remote-helpers.txt @@ -35,6 +35,37 @@ 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. +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. + INPUT FORMAT ------------ @@ -57,53 +88,17 @@ 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 *:*`. +In the following, we list all defined capabilities and for +each we list which commands a helper with that capability +must provide. Capabilities for Pushing -~~~~~~~~~~~~~~~~~~~~~~~~ +^^^^^^^^^^^^^^^^^^^^^^^^ 'connect':: Can attempt to connect to 'git receive-pack' (for pushing), - 'git upload-pack', etc for communication using the - packfile protocol. + 'git upload-pack', etc for communication using + git's native packfile protocol. This + requires a bidirectional, full-duplex connection. + Supported commands: 'connect'. @@ -113,16 +108,26 @@ Supported commands: 'connect'. + 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). +'export':: + Can discover remote refs and push specified objects from a + fast-import stream to remote refs. ++ +Supported commands: 'list for-push', 'export'. + +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 'push' and 'export', git prefers 'push'. +Other frontends may have some other order of preference. + Capabilities for Fetching -~~~~~~~~~~~~~~~~~~~~~~~~~ +^^^^^^^^^^^^^^^^^^^^^^^^^ 'connect':: Can try to connect to 'git upload-pack' (for fetching), 'git receive-pack', etc for communication using the - packfile protocol. + git's native packfile protocol. This + requires a bidirectional, full-duplex connection. + Supported commands: 'connect'. @@ -144,14 +149,27 @@ 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. +Miscellaneous capabilities +^^^^^^^^^^^^^^^^^^^^^^^^^^ + +'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. + 'refspec' <refspec>:: - This modifies the 'import' capability. + 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 +A helper advertising the capability `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. +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 @@ -159,36 +177,33 @@ 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 ----------- +'bidi-import':: + This modifies the 'import' capability. + The fast-import commands 'cat-blob' and 'ls' can be used by remote-helpers + to retrieve information about blobs and trees that already exist in + fast-import's memory. This requires a channel from fast-import to the + remote-helper. + If it is advertised in addition to "import", git establishes a pipe from + fast-import to the remote-helper's stdin. + It follows that git and fast-import are both connected to the + remote-helper's stdin. Because git can send multiple commands to + the remote-helper it is required that helpers that use 'bidi-import' + buffer all 'import' commands of a batch before sending data to fast-import. + This is to prevent mixing commands and fast-import responses on the + helper's stdin. -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. +'export-marks' <file>:: + This modifies the 'export' capability, instructing git to dump the + internal marks table to <file> when complete. For details, + read up on '--export-marks=<file>' in linkgit:git-fast-export[1]. + +'import-marks' <file>:: + This modifies the 'export' capability, instructing git to load the + marks specified in <file> before processing any input. For details, + read up on '--import-marks=<file>' in linkgit:git-fast-export[1]. -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 -------- @@ -198,9 +213,11 @@ 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). + which marks them mandatory for git versions using the remote + helper to understand. Any unknown mandatory capability is a + fatal error. ++ +Support for this command is mandatory. 'list':: Lists the refs, one per line, in the format "<value> <name> @@ -210,9 +227,20 @@ Commands are given by the caller on the helper's standard input, one per 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. +See REF LIST ATTRIBUTES for a list of currently defined attributes. ++ +Supported if the helper has the "fetch" or "import" capability. + +'list for-push':: + Similar to 'list', except that it is used if and only if + the caller wants to the resulting ref list to prepare + push commands. + A helper supporting both push and fetch can use this + to distinguish for which operation the output of 'list' + is going to be used, possibly reducing the amount + of work that needs to be performed. ++ +Supported if the helper has the "push" or "export" capability. 'option' <name> <value>:: Sets the transport helper option <name> to <value>. Outputs a @@ -222,6 +250,8 @@ commands to the helper. for it). Options should be set before other commands, and may influence the behavior of those commands. + +See OPTIONS for a list of currently defined options. ++ Supported if the helper has the "option" capability. 'fetch' <sha1> <name>:: @@ -230,7 +260,7 @@ Supported if the helper has the "option" capability. 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. + in the output of '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 @@ -286,8 +316,29 @@ terminated with a blank line. For each batch of 'import', the remote helper should produce a fast-import stream terminated by a 'done' command. + +Note that if the 'bidi-import' capability is used the complete batch +sequence has to be buffered before starting to send data to fast-import +to prevent mixing of commands and fast-import responses on the helper's +stdin. ++ Supported if the helper has the "import" capability. +'export':: + Instructs the remote helper that any subsequent input is + part of a fast-import stream (generated by 'git fast-export') + containing objects which should be pushed to the remote. ++ +Especially useful for interoperability with a foreign versioning +system. ++ +The 'export-marks' and 'import-marks' capabilities, if specified, +affect this command in so far as they are passed on to 'git +fast-export', which then will load/store a table of marks for +local objects. This can be used to implement for incremental +operations. ++ +Supported if the helper has the "export" capability. + 'connect' <service>:: Connects to given service. Standard input and standard output of helper are connected to specified service (git prefix is @@ -313,10 +364,9 @@ capabilities reported by the helper. 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. +The 'list' command produces a list of refs in which each ref +may be followed by a list of attributes. The following ref list +attributes are defined. 'unchanged':: This ref is unchanged since the last import or fetch, although @@ -324,6 +374,10 @@ REF LIST ATTRIBUTES OPTIONS ------- + +The following options are defined and (under suitable circumstances) +set by git if the remote helper has the 'option' capability. + 'option verbosity' <n>:: Changes the verbosity of messages displayed by the helper. A value of 0 for <n> means that processes operate |