git-sync is a simple command that pulls a git repository into a local directory. It is a perfect "sidecar" container in Kubernetes - it can periodically pull files down from a repository so that an application can consume them.
git-sync can pull one time, or on a regular interval. It can pull from the
HEAD of a branch, from a git tag, or from a specific git hash. It will only
re-pull if the target of the run has changed in the upstream repository. When
it re-pulls, it updates the destination directory atomically. In order to do
this, it uses a git worktree in a subdirectory of the --root and flips a
symlink.
git-sync can pull over HTTP(S) (with authentication or not) or SSH.
git-sync can also be configured to make a webhook call upon successful git repo synchronization. The call is made after the symlink is updated.
We use docker buildx to build images.
# build the container
make container REGISTRY=registry VERSION=tag
# build the container behind a proxy
make container REGISTRY=registry VERSION=tag \
HTTP_PROXY=http://<proxy_address>:<proxy_port> \
HTTPS_PROXY=https://<proxy_address>:<proxy_port>
# build the container for an OS/arch other than the current (e.g. you are on
# MacOS and want to run on Linux)
make container REGISTRY=registry VERSION=tag \
GOOS=linux GOARCH=amd64
# make a directory (owned by you) for the volume
export DIR="/tmp/git-data"
mkdir -p $DIR
# run the container (as your own UID)
# run the container
docker run -d \
-v $DIR:/tmp/git \
-u$(id -u):$(id -g) \
registry/git-sync:tag \
--repo=https://github.com/kubernetes/git-sync \
--root=/tmp/git/root \
--period=30s
# run an nginx container to serve the content
docker run -d \
-p 8080:80 \
-v $DIR:/usr/share/nginx/html \
nginx
GIT-SYNC
NAME
git-sync - sync a remote git repository
SYNOPSIS
git-sync --repo=<repo> [OPTION]...
DESCRIPTION
Fetch a remote git repository to a local directory, poll the remote for
changes, and update the local copy.
This is a perfect "sidecar" container in Kubernetes. For example, it can
periodically pull files down from a repository so that an application can
consume them.
git-sync can pull one time, or on a regular interval. It can read from the
HEAD of a branch, from a git tag, or from a specific git hash. It will only
re-pull if the target has changed in the remote repository. When it
re-pulls, it updates the destination directory atomically. In order to do
this, it uses a git worktree in a subdirectory of the --root and flips a
symlink.
git-sync can pull over HTTP(S) (with authentication or not) or SSH.
git-sync can also be configured to make a webhook call upon successful git
repo synchronization. The call is made after the symlink is updated.
OPTIONS
Many options can be specified as either a commandline flag or an environment
variable.
--add-user, $GIT_SYNC_ADD_USER
Add a record to /etc/passwd for the current UID/GID. This is needed
to use SSH (see --ssh) with an arbitrary UID. This assumes that
/etc/passwd is writable by the current UID.
--askpass-url <string>, $GIT_ASKPASS_URL
A URL to query for git credentials. The query must return success
(200) and produce a series of key=value lines, including
"username=<value>" and "password=<value>".
--branch <string>, $GIT_SYNC_BRANCH
The git branch to check out. (default: <repo's default branch>)
--change-permissions <int>, $GIT_SYNC_PERMISSIONS
Optionally change permissions on the checked-out files to the
specified mode.
--cookie-file, $GIT_COOKIE_FILE
Use a git cookiefile (/etc/git-secret/cookie_file) for
authentication.
--error-file, $GIT_SYNC_ERROR_FILE
The name of a file (under --root) into which errors will be
written. This must be a filename, not a path, and may not start
with a period. (default: "", which means error reporting will be
disabled)
--depth <int>, $GIT_SYNC_DEPTH
Create a shallow clone with history truncated to the specified
number of commits.
--git <string>, $GIT_SYNC_GIT
The git command to run (subject to PATH search, mostly for testing).
(default: git)
--git-config <string>, $GIT_SYNC_GIT_CONFIG
Additional git config options in 'key1:val1,key2:val2' format. The
key parts are passed to 'git config' and must be valid syntax for
that command. The val parts can be either quoted or unquoted
values. For all values the following escape sequences are
supported: '\n' => [newline], '\t' => [tab], '\"' => '"', '\,' =>
',', '\\' => '\'. Within unquoted values, commas MUST be escaped.
Within quoted values, commas MAY be escaped, but are not required
to be. Any other escape sequence is an error. (default: "")
-h, --help
Print help text and exit.
--http-bind <string>, $GIT_SYNC_HTTP_BIND
The bind address (including port) for git-sync's HTTP endpoint.
(default: none)
--http-metrics, $GIT_SYNC_HTTP_METRICS
Enable metrics on git-sync's HTTP endpoint (see --http-bind).
(default: true)
--http-pprof, $GIT_SYNC_HTTP_PPROF
Enable the pprof debug endpoints on git-sync's HTTP endpoint (see
--http-bind). (default: false)
--link <string>, $GIT_SYNC_LINK
The name of the final symlink (under --root) which will point to the
current git worktree. This must be a filename, not a path, and may
not start with a period. The destination of this link (i.e.
readlink()) is the currently checked out SHA. (default: the leaf
dir of --repo)
--man
Print this manual and exit.
--max-sync-failures <int>, $GIT_SYNC_MAX_SYNC_FAILURES
The number of consecutive failures allowed before aborting (the
first sync must succeed), Setting this to -1 will retry forever
after the initial sync. (default: 0)
--one-time, $GIT_SYNC_ONE_TIME
Exit after the first sync.
--password <string>, $GIT_SYNC_PASSWORD
The password or personal access token (see github docs) to use for
git authentication (see --username). NOTE: for security reasons,
users should prefer using a file for specifying the password (see
--password-file).
--password-file <string>, $GIT_SYNC_PASSWORD_FILE
The path to password file which contains password or personal access
token (see --password).
--period <duration>, $GIT_SYNC_PERIOD
How long to wait between sync attempts. This must be at least
10ms. This flag obsoletes --wait, but if --wait is specified, it
will take precedence. (default: 10s)
--repo <string>, $GIT_SYNC_REPO
The git repository to sync.
--rev <string>, $GIT_SYNC_REV
The git revision (tag or hash) to check out. (default: HEAD)
--root <string>, $GIT_SYNC_ROOT
The root directory for git-sync operations, under which --link will
be created. This flag is required.
--sparse-checkout-file, $GIT_SYNC_SPARSE_CHECKOUT_FILE
The path to a git sparse-checkout file (see git documentation for
details) which controls which files and directories will be checked
out.
--ssh, $GIT_SYNC_SSH
Use SSH for git authentication and operations.
--ssh-key-file <string>, $GIT_SSH_KEY_FILE
The SSH key to use when using --ssh. (default: /etc/git-secret/ssh)
--ssh-known-hosts, $GIT_KNOWN_HOSTS
Enable SSH known_hosts verification when using --ssh.
(default: true)
--ssh-known-hosts-file <string>, $GIT_SSH_KNOWN_HOSTS_FILE
The known_hosts file to use when --ssh-known-hosts is specified.
(default: /etc/git-secret/known_hosts)
--submodules <string>, $GIT_SYNC_SUBMODULES
The git submodule behavior: one of 'recursive', 'shallow', or 'off'.
(default: recursive)
--sync-hook-command <string>, $GIT_SYNC_HOOK_COMMAND
An optional command to be executed after syncing a new hash of the
remote repository. This command does not take any arguments and
executes with the synced repo as its working directory. The
execution is subject to the overall --sync-timeout flag and will
extend the effective period between sync attempts.
--sync-timeout <duration>, $GIT_SYNC_SYNC_TIMEOUT
The total time allowed for one complete sync. This must be at least
10ms. This flag obsoletes --timeout, but if --timeout is specified,
it will take precedence. (default: 120s)
--username <string>, $GIT_SYNC_USERNAME
The username to use for git authentication (see --password).
-v, --verbose <int>
Set the log verbosity level. Logs at this level and lower will be
printed. (default: 0)
--version
Print the version and exit.
--webhook-backoff <duration>, $GIT_SYNC_WEBHOOK_BACKOFF
The time to wait before retrying a failed --webhook-url).
(default: 3s)
--webhook-method <string>, $GIT_SYNC_WEBHOOK_METHOD
The HTTP method for the --webhook-url (default: POST)
--webhook-success-status <int>, $GIT_SYNC_WEBHOOK_SUCCESS_STATUS
The HTTP status code indicating a successful --webhook-url. Setting
this to -1 disables success checks to make webhooks fire-and-forget.
(default: 200)
--webhook-timeout <duration>, $GIT_SYNC_WEBHOOK_TIMEOUT
The timeout for the --webhook-url. (default: 1s)
--webhook-url <string>, $GIT_SYNC_WEBHOOK_URL
A URL for optional webhook notifications when syncs complete.
EXAMPLE USAGE
git-sync \
--repo=https://github.com/kubernetes/git-sync \
--branch=main \
--rev=HEAD \
--period=10s \
--root=/mnt/git
AUTHENTICATION
Git-sync offers several authentication options to choose from. If none of
the following are specified, git-sync will try to access the repo in the
"natural" manner. For example, "https://repo" will try to use plain HTTPS
and "[email protected]:repo" will try to use SSH.
username/password
The --username (GIT_SYNC_USERNAME) and --password
(GIT_SYNC_PASSWORD) flags will be used. To prevent password
leaks, the GIT_SYNC_PASSWORD environment variable is almost always
preferred to the flag.
A variant of this is --askpass-url (GIT_ASKPASS_URL), which
consults a URL (e.g. http://metadata) to get credentials on each
sync.
SSH
When --ssh (GIT_SYNC_SSH) is specified, the --ssh-key-file
(GIT_SSH_KEY_FILE) will be used. Users are strongly advised to
also use --ssh-known-hosts (GIT_KNOWN_HOSTS) and
--ssh-known-hosts-file (GIT_SSH_KNOWN_HOSTS_FILE) when using SSH.
cookies
When --cookie-file (GIT_COOKIE_FILE) is specified, the associated
cookies can contain authentication information.
WEBHOOKS
Webhooks are executed asynchronously from the main git-sync process. If a
--webhook-url is configured, whenever a new hash is synced a call is sent
using the method defined in --webhook-method. Git-sync will retry this
webhook call until it succeeds (based on --webhook-success-status). If
unsuccessful, git-sync will wait --webhook-backoff (default 3s) before
re-attempting the webhook call.