Documentation/git-receive-pack.txt - jrn/git - Git at Google

 git-receive-pack(1)
 ===================

 NAME
 ----
 git-receive-pack - Receive what is pushed into the repository


 SYNOPSIS
 --------
 [verse]
 'git-receive-pack' <directory>

 DESCRIPTION
 -----------
 Invoked by 'git send-pack' and updates the repository with the
 information fed from the remote end.

 This command is usually not invoked directly by the end user.
 The UI for the protocol is on the 'git send-pack' side, and the
 program pair is meant to be used to push updates to remote
 repository.  For pull operations, see linkgit:git-fetch-pack[1].

 The command allows for creation and fast-forwarding of sha1 refs
 (heads/tags) on the remote end (strictly speaking, it is the
 local end 'git-receive-pack' runs, but to the user who is sitting at
 the send-pack end, it is updating the remote.  Confused?)

 There are other real-world examples of using update and
 post-update hooks found in the Documentation/howto directory.

 'git-receive-pack' honours the receive.denyNonFastForwards config
 option, which tells it if updates to a ref should be denied if they
 are not fast-forwards.

 A number of other receive.* config options are available to tweak
 its behavior, see linkgit:git-config[1].

 OPTIONS
 -------
 <directory>::
 	The repository to sync into.

 PRE-RECEIVE HOOK
 ----------------
 Before any ref is updated, if $GIT_DIR/hooks/pre-receive file exists
 and is executable, it will be invoked once with no parameters.  The
 standard input of the hook will be one line per ref to be updated:

        sha1-old SP sha1-new SP refname LF

 The refname value is relative to $GIT_DIR; e.g. for the master
 head this is "refs/heads/master".  The two sha1 values before
 each refname are the object names for the refname before and after
 the update.  Refs to be created will have sha1-old equal to 0\{40},
 while refs to be deleted will have sha1-new equal to 0\{40}, otherwise
 sha1-old and sha1-new should be valid objects in the repository.

 When accepting a signed push (see linkgit:git-push[1]), the signed
 push certificate is stored in a blob and an environment variable
 `GIT_PUSH_CERT` can be consulted for its object name.  See the
 description of `post-receive` hook for an example.  In addition, the
 certificate is verified using GPG and the result is exported with
 the following environment variables:

 `GIT_PUSH_CERT_SIGNER`::
 	The name and the e-mail address of the owner of the key that
 	signed the push certificate.

 `GIT_PUSH_CERT_KEY`::
 	The GPG key ID of the key that signed the push certificate.

 `GIT_PUSH_CERT_STATUS`::
 	The status of GPG verification of the push certificate,
 	using the same mnemonic as used in `%G?` format of `git log`
 	family of commands (see linkgit:git-log[1]).

 `GIT_PUSH_CERT_NONCE`::
 	The nonce string the process asked the signer to include
 	in the push certificate.  If this does not match the value
 	recorded on the "nonce" header in the push certificate, it
 	may indicate that the certificate is a valid one that is
 	being replayed from a separate "git push" session.

 `GIT_PUSH_CERT_NONCE_STATUS`::
 `UNSOLICITED`;;
 	"git push --signed" sent a nonce when we did not ask it to
 	send one.
 `MISSING`;;
 	"git push --signed" did not send any nonce header.
 `BAD`;;
 	"git push --signed" sent a bogus nonce.
 `OK`;;
 	"git push --signed" sent the nonce we asked it to send.
 `SLOP`;;
 	"git push --signed" sent a nonce different from what we
 	asked it to send now, but in a previous session.  See
 	`GIT_PUSH_CERT_NONCE_SLOP` environment variable.

 `GIT_PUSH_CERT_NONCE_SLOP`::
 	"git push --signed" sent a nonce different from what we
 	asked it to send now, but in a different session whose
 	starting time is different by this many seconds from the
 	current session.  Only meaningful when
 	`GIT_PUSH_CERT_NONCE_STATUS` says `SLOP`.
 	Also read about `receive.certNonceSlop` variable in
 	linkgit:git-config[1].

 This hook is called before any refname is updated and before any
 fast-forward checks are performed.

 If the pre-receive hook exits with a non-zero exit status no updates
 will be performed, and the update, post-receive and post-update
 hooks will not be invoked either.  This can be useful to quickly
 bail out if the update is not to be supported.

 See the notes on the quarantine environment below.

 UPDATE HOOK
 -----------
 Before each ref is updated, if $GIT_DIR/hooks/update file exists
 and is executable, it is invoked once per ref, with three parameters:

        $GIT_DIR/hooks/update refname sha1-old sha1-new

 The refname parameter is relative to $GIT_DIR; e.g. for the master
 head this is "refs/heads/master".  The two sha1 arguments are
 the object names for the refname before and after the update.
 Note that the hook is called before the refname is updated,
 so either sha1-old is 0\{40} (meaning there is no such ref yet),
 or it should match what is recorded in refname.

 The hook should exit with non-zero status if it wants to disallow
 updating the named ref.  Otherwise it should exit with zero.

 Successful execution (a zero exit status) of this hook does not
 ensure the ref will actually be updated, it is only a prerequisite.
 As such it is not a good idea to send notices (e.g. email) from
 this hook.  Consider using the post-receive hook instead.

 POST-RECEIVE HOOK
 -----------------
 After all refs were updated (or attempted to be updated), if any
 ref update was successful, and if $GIT_DIR/hooks/post-receive
 file exists and is executable, it will be invoked once with no
 parameters.  The standard input of the hook will be one line
 for each successfully updated ref:

        sha1-old SP sha1-new SP refname LF

 The refname value is relative to $GIT_DIR; e.g. for the master
 head this is "refs/heads/master".  The two sha1 values before
 each refname are the object names for the refname before and after
 the update.  Refs that were created will have sha1-old equal to
 0\{40}, while refs that were deleted will have sha1-new equal to
 0\{40}, otherwise sha1-old and sha1-new should be valid objects in
 the repository.

 The `GIT_PUSH_CERT*` environment variables can be inspected, just as
 in `pre-receive` hook, after accepting a signed push.

 Using this hook, it is easy to generate mails describing the updates
 to the repository.  This example script sends one mail message per
 ref listing the commits pushed to the repository, and logs the push
 certificates of signed pushes with good signatures to a logger
 service:

 ----
 #!/bin/sh
 # mail out commit update information.
 while read oval nval ref
 do
 	if expr "$oval" : '0*$' >/dev/null
 	then
 		echo "Created a new ref, with the following commits:"
 		git rev-list --pretty "$nval"
 	else
 		echo "New commits:"
 		git rev-list --pretty "$nval" "^$oval"
 	fi |
 	mail -s "Changes to ref $ref" commit-list@mydomain
 done
 # log signed push certificate, if any
 if test -n "${GIT_PUSH_CERT-}" && test ${GIT_PUSH_CERT_STATUS} = G
 then
 	(
 		echo expected nonce is ${GIT_PUSH_NONCE}
 		git cat-file blob ${GIT_PUSH_CERT}
 	) | mail -s "push certificate from $GIT_PUSH_CERT_SIGNER" push-log@mydomain
 fi
 exit 0
 ----

 The exit code from this hook invocation is ignored, however a
 non-zero exit code will generate an error message.

 Note that it is possible for refname to not have sha1-new when this
 hook runs.  This can easily occur if another user modifies the ref
 after it was updated by 'git-receive-pack', but before the hook was able
 to evaluate it.  It is recommended that hooks rely on sha1-new
 rather than the current value of refname.

 POST-UPDATE HOOK
 ----------------
 After all other processing, if at least one ref was updated, and
 if $GIT_DIR/hooks/post-update file exists and is executable, then
 post-update will be called with the list of refs that have been updated.
 This can be used to implement any repository wide cleanup tasks.

 The exit code from this hook invocation is ignored; the only thing
 left for 'git-receive-pack' to do at that point is to exit itself
 anyway.

 This hook can be used, for example, to run `git update-server-info`
 if the repository is packed and is served via a dumb transport.

 ----
 #!/bin/sh
 exec git update-server-info
 ----


 QUARANTINE ENVIRONMENT
 ----------------------

 When `receive-pack` takes in objects, they are placed into a temporary
 "quarantine" directory within the `$GIT_DIR/objects` directory and
 migrated into the main object store only after the `pre-receive` hook
 has completed. If the push fails before then, the temporary directory is
 removed entirely.

 This has a few user-visible effects and caveats:

   1. Pushes which fail due to problems with the incoming pack, missing
      objects, or due to the `pre-receive` hook will not leave any
      on-disk data. This is usually helpful to prevent repeated failed
      pushes from filling up your disk, but can make debugging more
      challenging.

   2. Any objects created by the `pre-receive` hook will be created in
      the quarantine directory (and migrated only if it succeeds).

   3. The `pre-receive` hook MUST NOT update any refs to point to
      quarantined objects. Other programs accessing the repository will
      not be able to see the objects (and if the pre-receive hook fails,
      those refs would become corrupted). For safety, any ref updates
      from within `pre-receive` are automatically rejected.


 SEE ALSO
 --------
 linkgit:git-send-pack[1], linkgit:gitnamespaces[7]

 GIT
 ---
 Part of the linkgit:git[1] suite
	git-receive-pack(1)
	===================

	NAME
	----
	git-receive-pack - Receive what is pushed into the repository


	SYNOPSIS
	--------
	[verse]
	'git-receive-pack' <directory>

	DESCRIPTION
	-----------
	Invoked by 'git send-pack' and updates the repository with the
	information fed from the remote end.

	This command is usually not invoked directly by the end user.
	The UI for the protocol is on the 'git send-pack' side, and the
	program pair is meant to be used to push updates to remote
	repository. For pull operations, see linkgit:git-fetch-pack[1].

	The command allows for creation and fast-forwarding of sha1 refs
	(heads/tags) on the remote end (strictly speaking, it is the
	local end 'git-receive-pack' runs, but to the user who is sitting at
	the send-pack end, it is updating the remote. Confused?)

	There are other real-world examples of using update and
	post-update hooks found in the Documentation/howto directory.

	'git-receive-pack' honours the receive.denyNonFastForwards config
	option, which tells it if updates to a ref should be denied if they
	are not fast-forwards.

	A number of other receive.* config options are available to tweak
	its behavior, see linkgit:git-config[1].

	OPTIONS
	-------
	<directory>::
	The repository to sync into.

	PRE-RECEIVE HOOK
	----------------
	Before any ref is updated, if $GIT_DIR/hooks/pre-receive file exists
	and is executable, it will be invoked once with no parameters. The
	standard input of the hook will be one line per ref to be updated:

	sha1-old SP sha1-new SP refname LF

	The refname value is relative to $GIT_DIR; e.g. for the master
	head this is "refs/heads/master". The two sha1 values before
	each refname are the object names for the refname before and after
	the update. Refs to be created will have sha1-old equal to 0\{40},
	while refs to be deleted will have sha1-new equal to 0\{40}, otherwise
	sha1-old and sha1-new should be valid objects in the repository.

	When accepting a signed push (see linkgit:git-push[1]), the signed
	push certificate is stored in a blob and an environment variable
	`GIT_PUSH_CERT` can be consulted for its object name. See the
	description of `post-receive` hook for an example. In addition, the
	certificate is verified using GPG and the result is exported with
	the following environment variables:

	`GIT_PUSH_CERT_SIGNER`::
	The name and the e-mail address of the owner of the key that
	signed the push certificate.

	`GIT_PUSH_CERT_KEY`::
	The GPG key ID of the key that signed the push certificate.

	`GIT_PUSH_CERT_STATUS`::
	The status of GPG verification of the push certificate,
	using the same mnemonic as used in `%G?` format of `git log`
	family of commands (see linkgit:git-log[1]).

	`GIT_PUSH_CERT_NONCE`::
	The nonce string the process asked the signer to include
	in the push certificate. If this does not match the value
	recorded on the "nonce" header in the push certificate, it
	may indicate that the certificate is a valid one that is
	being replayed from a separate "git push" session.

	`GIT_PUSH_CERT_NONCE_STATUS`::
	`UNSOLICITED`;;
	"git push --signed" sent a nonce when we did not ask it to
	send one.
	`MISSING`;;
	"git push --signed" did not send any nonce header.
	`BAD`;;
	"git push --signed" sent a bogus nonce.
	`OK`;;
	"git push --signed" sent the nonce we asked it to send.
	`SLOP`;;
	"git push --signed" sent a nonce different from what we
	asked it to send now, but in a previous session. See
	`GIT_PUSH_CERT_NONCE_SLOP` environment variable.

	`GIT_PUSH_CERT_NONCE_SLOP`::
	"git push --signed" sent a nonce different from what we
	asked it to send now, but in a different session whose
	starting time is different by this many seconds from the
	current session. Only meaningful when
	`GIT_PUSH_CERT_NONCE_STATUS` says `SLOP`.
	Also read about `receive.certNonceSlop` variable in
	linkgit:git-config[1].

	This hook is called before any refname is updated and before any
	fast-forward checks are performed.

	If the pre-receive hook exits with a non-zero exit status no updates
	will be performed, and the update, post-receive and post-update
	hooks will not be invoked either. This can be useful to quickly
	bail out if the update is not to be supported.

	See the notes on the quarantine environment below.

	UPDATE HOOK
	-----------
	Before each ref is updated, if $GIT_DIR/hooks/update file exists
	and is executable, it is invoked once per ref, with three parameters:

	$GIT_DIR/hooks/update refname sha1-old sha1-new

	The refname parameter is relative to $GIT_DIR; e.g. for the master
	head this is "refs/heads/master". The two sha1 arguments are
	the object names for the refname before and after the update.
	Note that the hook is called before the refname is updated,
	so either sha1-old is 0\{40} (meaning there is no such ref yet),
	or it should match what is recorded in refname.

	The hook should exit with non-zero status if it wants to disallow
	updating the named ref. Otherwise it should exit with zero.

	Successful execution (a zero exit status) of this hook does not
	ensure the ref will actually be updated, it is only a prerequisite.
	As such it is not a good idea to send notices (e.g. email) from
	this hook. Consider using the post-receive hook instead.

	POST-RECEIVE HOOK
	-----------------
	After all refs were updated (or attempted to be updated), if any
	ref update was successful, and if $GIT_DIR/hooks/post-receive
	file exists and is executable, it will be invoked once with no
	parameters. The standard input of the hook will be one line
	for each successfully updated ref:

	sha1-old SP sha1-new SP refname LF

	The refname value is relative to $GIT_DIR; e.g. for the master
	head this is "refs/heads/master". The two sha1 values before
	each refname are the object names for the refname before and after
	the update. Refs that were created will have sha1-old equal to
	0\{40}, while refs that were deleted will have sha1-new equal to
	0\{40}, otherwise sha1-old and sha1-new should be valid objects in
	the repository.

	The `GIT_PUSH_CERT*` environment variables can be inspected, just as
	in `pre-receive` hook, after accepting a signed push.

	Using this hook, it is easy to generate mails describing the updates
	to the repository. This example script sends one mail message per
	ref listing the commits pushed to the repository, and logs the push
	certificates of signed pushes with good signatures to a logger
	service:

	----
	#!/bin/sh
	# mail out commit update information.
	while read oval nval ref
	do
	if expr "$oval" : '0*$' >/dev/null
	then
	echo "Created a new ref, with the following commits:"
	git rev-list --pretty "$nval"
	else
	echo "New commits:"
	git rev-list --pretty "$nval" "^$oval"
	fi \|
	mail -s "Changes to ref $ref" commit-list@mydomain
	done
	# log signed push certificate, if any
	if test -n "${GIT_PUSH_CERT-}" && test ${GIT_PUSH_CERT_STATUS} = G
	then
	(
	echo expected nonce is ${GIT_PUSH_NONCE}
	git cat-file blob ${GIT_PUSH_CERT}
	) \| mail -s "push certificate from $GIT_PUSH_CERT_SIGNER" push-log@mydomain
	fi
	exit 0
	----

	The exit code from this hook invocation is ignored, however a
	non-zero exit code will generate an error message.

	Note that it is possible for refname to not have sha1-new when this
	hook runs. This can easily occur if another user modifies the ref
	after it was updated by 'git-receive-pack', but before the hook was able
	to evaluate it. It is recommended that hooks rely on sha1-new
	rather than the current value of refname.

	POST-UPDATE HOOK
	----------------
	After all other processing, if at least one ref was updated, and
	if $GIT_DIR/hooks/post-update file exists and is executable, then
	post-update will be called with the list of refs that have been updated.
	This can be used to implement any repository wide cleanup tasks.

	The exit code from this hook invocation is ignored; the only thing
	left for 'git-receive-pack' to do at that point is to exit itself
	anyway.

	This hook can be used, for example, to run `git update-server-info`
	if the repository is packed and is served via a dumb transport.

	----
	#!/bin/sh
	exec git update-server-info
	----


	QUARANTINE ENVIRONMENT
	----------------------

	When `receive-pack` takes in objects, they are placed into a temporary
	"quarantine" directory within the `$GIT_DIR/objects` directory and
	migrated into the main object store only after the `pre-receive` hook
	has completed. If the push fails before then, the temporary directory is
	removed entirely.

	This has a few user-visible effects and caveats:

	1. Pushes which fail due to problems with the incoming pack, missing
	objects, or due to the `pre-receive` hook will not leave any
	on-disk data. This is usually helpful to prevent repeated failed
	pushes from filling up your disk, but can make debugging more
	challenging.

	2. Any objects created by the `pre-receive` hook will be created in
	the quarantine directory (and migrated only if it succeeds).

	3. The `pre-receive` hook MUST NOT update any refs to point to
	quarantined objects. Other programs accessing the repository will
	not be able to see the objects (and if the pre-receive hook fails,
	those refs would become corrupted). For safety, any ref updates
	from within `pre-receive` are automatically rejected.


	SEE ALSO
	--------
	linkgit:git-send-pack[1], linkgit:gitnamespaces[7]

	GIT
	---
	Part of the linkgit:git[1] suite