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Diffstat (limited to 'Documentation/git-remote-helpers.txt')
| -rw-r--r-- | Documentation/git-remote-helpers.txt | 260 |
1 files changed, 218 insertions, 42 deletions
diff --git a/Documentation/git-remote-helpers.txt b/Documentation/git-remote-helpers.txt index 18b8341f24..6d696e0f90 100644 --- a/Documentation/git-remote-helpers.txt +++ b/Documentation/git-remote-helpers.txt @@ -7,6 +7,7 @@ git-remote-helpers - Helper programs to interact with remote repositories SYNOPSIS -------- +[verse] 'git remote-<transport>' <repository> [<URL>] DESCRIPTION @@ -23,16 +24,11 @@ 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. +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', @@ -70,6 +66,145 @@ Additionally, when a configured remote has 'remote.<name>.vcs' set to '<name>' as the first argument. If set, the second argument is 'remote.<name>.url'; otherwise, the second argument is omitted. +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). + +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 + git's native packfile protocol. This + requires a bidirectional, full-duplex connection. ++ +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'. + +'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 + git's native packfile protocol. This + requires a bidirectional, full-duplex connection. ++ +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. + +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, 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 *:*`. + +'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. + +'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]. + + + + COMMANDS -------- @@ -78,9 +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> @@ -90,9 +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 @@ -102,6 +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>:: @@ -110,7 +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 @@ -121,7 +271,22 @@ 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. + 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. @@ -146,8 +311,34 @@ Supported if the helper has the "push" capability. 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. ++ +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 @@ -170,33 +361,12 @@ 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/{asterisk}:refs/svn/origin/branches/{asterisk}" 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 "{asterisk}:{asterisk}" - 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 @@ -204,6 +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 @@ -242,6 +416,8 @@ SEE ALSO -------- linkgit:git-remote[1] +linkgit:git-remote-testgit[1] + GIT --- Part of the linkgit:git[1] suite |