How the gitlab-ci cache is working on docker runner?
What is /cache directory?
What is cache_dir?
Where and how files matching the "paths" in "cache" gitlab-ci.yml are stored?
Volume mounted to /cache directory is created automatically on gitlab-runner installation and managed by cache_dir setting
more about cache_dir:
If you modify the /cache storage path, you also need to make sure to mark this
directory as persistent by defining it in volumes = ["/my/cache/"] under the
[runners.docker] section in config.toml.
/cache dir is different from cache config in gitlab-ci.yml
/cache dir in job container is where the cached files are storedcache config in gitlab-ci.yml are copied to /cache/$CI_PROJECT_NAMESPACE/$CI_PROJECT_NAME/<cache-key>-<cache-number> at the end of job/cache/$CI_PROJECT_NAMESPACE/$CI_PROJECT_NAME/<cache-key>-<cache-number>/cache.zip to dir specified in cache config in gitlab-ci.yml (Instead of "removing content of /cache folder as I though at first)P.S.
There is container named gitlab-runner-cache created on machine with gitlab-runner (https://gitlab.com/gitlab-org/gitlab-runner/blob/af343971874198a1923352107409583b78e8aa80/executors/docker/executor_docker.go#L382)
(Seems like) This container is used to create anonymous volume where /cache data is stored. After the anonymous volume is created this container is stopped.
The job containers (meaning container were your tests typically run) mounts this anonymous volume
HAVING gitlab-ci.yml
image: srghma/docker-nixos-with-git-crypt
cache:
key: "test00000" # to reset cache - change this key OR clear cache in project settings page
paths:
- .mycache # gitlab allows only cache dirs that are relative to project root OR /cache (created automatically)
testtest:
script:
- nix-env -i tree
- tree --dirsfirst -L 4 /cache
- ls -al ./.mycache || true
- echo "test" > /cache/test
- mkdir -p ./.mycache
- echo "test" > ./.mycache/test
- tree --dirsfirst -L 4 /cache
- ls -al ./.mycache || true
Output:
Running with gitlab-runner 11.6.0 (f100a208)
on srghma_gitlab_runner 9b3980da
Using Docker executor with image srghma/docker-nixos-with-git-crypt ...
Pulling docker image srghma/docker-nixos-with-git-crypt ...
Using docker image sha256:ad3491aae178f629df713e0719750cc445b4881702b6b04b7cf325121f0032bf for srghma/docker-nixos-with-git-crypt ...
Running on runner-9b3980da-project-222-concurrent-0 via myrunner.com...
Fetching changes...
Removing .mycache/
HEAD is now at 675caa7 feat: cache update
From https://gitlab.com/srghma/myproject
675caa7..3d1e223 nix -> origin/nix
Checking out 3d1e2237 as nix...
Skipping Git submodules setup
Checking cache for test00000-11...
No URL provided, cache will be not downloaded from shared cache server. Instead a local version of cache will be extracted.
Successfully extracted cache
$ nix-env -i tree
installing 'tree-1.8.0'
these paths will be fetched (0.03 MiB download, 0.09 MiB unpacked):
/nix/store/dhfq0dsg9a0j5ai78bmh5qlrla8wvcxz-tree-1.8.0
copying path '/nix/store/dhfq0dsg9a0j5ai78bmh5qlrla8wvcxz-tree-1.8.0' from 'https://cache.nixos.org'...
building '/nix/store/dankqr2x4g5igc4w7lw9xqnn7lcy4f7a-user-environment.drv'...
created 233 symlinks in user environment
$ tree --dirsfirst -L 4 /cache
/cache
0 directories, 0 files
$ ls -al ./.mycache || true
$ echo "test" > /cache/test
ls: ./.mycache: No such file or directory
$ mkdir -p ./.mycache
$ echo "test" > ./.mycache/test
$ tree --dirsfirst -L 4 /cache
/cache
`-- test
0 directories, 1 file
$ ls -al ./.mycache || true
total 12
drwxr-xr-x 2 root root 4096 Feb 24 11:44 .
drwxrwxrwx 20 root root 4096 Feb 24 11:44 ..
-rw-r--r-- 1 root root 5 Feb 24 11:44 test
Creating cache test00000-11...
.mycache: found 2 matching files
No URL provided, cache will be not uploaded to shared cache server. Cache will be stored only locally.
Created cache
Job succeeded
Running with gitlab-runner 11.6.0 (f100a208)
on srghma_gitlab_runner 9b3980da
Using Docker executor with image srghma/docker-nixos-with-git-crypt ...
Pulling docker image srghma/docker-nixos-with-git-crypt ...
Using docker image sha256:ad3491aae178f629df713e0719750cc445b4881702b6b04b7cf325121f0032bf for srghma/docker-nixos-with-git-crypt ...
Running on runner-9b3980da-project-222-concurrent-0 via myrunner.com...
Fetching changes...
Removing .mycache/
HEAD is now at 3d1e223 feat: cache update
Checking out 3d1e2237 as nix...
Skipping Git submodules setup
Checking cache for test00000-11...
No URL provided, cache will be not downloaded from shared cache server. Instead a local version of cache will be extracted.
Successfully extracted cache
$ nix-env -i tree
installing 'tree-1.8.0'
these paths will be fetched (0.03 MiB download, 0.09 MiB unpacked):
/nix/store/dhfq0dsg9a0j5ai78bmh5qlrla8wvcxz-tree-1.8.0
copying path '/nix/store/dhfq0dsg9a0j5ai78bmh5qlrla8wvcxz-tree-1.8.0' from 'https://cache.nixos.org'...
building '/nix/store/dankqr2x4g5igc4w7lw9xqnn7lcy4f7a-user-environment.drv'...
created 233 symlinks in user environment
$ tree --dirsfirst -L 4 /cache
/cache
|-- srghma
| `-- myproject
| `-- test00000-11
| `-- cache.zip
`-- test
3 directories, 2 files
$ ls -al ./.mycache || true
total 12
drwxr-xr-x 2 root root 4096 Feb 24 11:44 .
drwxrwxrwx 20 root root 4096 Feb 24 11:44 ..
-rw-r--r-- 1 root root 5 Feb 24 11:44 test
$ echo "test" > /cache/test
$ mkdir -p ./.mycache
$ echo "test" > ./.mycache/test
$ tree --dirsfirst -L 4 /cache
/cache
|-- srghma
| `-- myproject
| `-- test00000-11
| `-- cache.zip
`-- test
3 directories, 2 files
$ ls -al ./.mycache || true
total 12
drwxr-xr-x 2 root root 4096 Feb 24 11:44 .
drwxrwxrwx 20 root root 4096 Feb 24 11:44 ..
-rw-r--r-- 1 root root 5 Feb 24 11:44 test
Creating cache test00000-11...
.mycache: found 2 matching files
No URL provided, cache will be not uploaded to shared cache server. Cache will be stored only locally.
Created cache
Job succeeded
Running with gitlab-runner 11.6.0 (f100a208)
on srghma_gitlab_runner 9b3980da
Using Docker executor with image srghma/docker-nixos-with-git-crypt ...
Pulling docker image srghma/docker-nixos-with-git-crypt ...
Using docker image sha256:ad3491aae178f629df713e0719750cc445b4881702b6b04b7cf325121f0032bf for srghma/docker-nixos-with-git-crypt ...
Running on runner-9b3980da-project-222-concurrent-0 via myrunner.com...
Fetching changes...
Removing .mycache/
HEAD is now at 3d1e223 feat: cache update
Checking out 3d1e2237 as nix...
Skipping Git submodules setup
Checking cache for test00000-12...
No URL provided, cache will be not downloaded from shared cache server. Instead a local version of cache will be extracted.
Successfully extracted cache
$ nix-env -i tree
installing 'tree-1.8.0'
these paths will be fetched (0.03 MiB download, 0.09 MiB unpacked):
/nix/store/dhfq0dsg9a0j5ai78bmh5qlrla8wvcxz-tree-1.8.0
copying path '/nix/store/dhfq0dsg9a0j5ai78bmh5qlrla8wvcxz-tree-1.8.0' from 'https://cache.nixos.org'...
building '/nix/store/dankqr2x4g5igc4w7lw9xqnn7lcy4f7a-user-environment.drv'...
created 233 symlinks in user environment
$ tree --dirsfirst -L 4 /cache
/cache
|-- srghma
| `-- myproject
| `-- test00000-11
| `-- cache.zip
`-- test
3 directories, 2 files
$ ls -al ./.mycache || true
ls: ./.mycache: No such file or directory
$ echo "test" > /cache/test
$ mkdir -p ./.mycache
$ echo "test" > ./.mycache/test
$ tree --dirsfirst -L 4 /cache
/cache
|-- srghma
| `-- myproject
| `-- test00000-11
| `-- cache.zip
`-- test
3 directories, 2 files
$ ls -al ./.mycache || true
total 12
drwxr-xr-x 2 root root 4096 Feb 24 11:45 .
drwxrwxrwx 20 root root 4096 Feb 24 11:45 ..
-rw-r--r-- 1 root root 5 Feb 24 11:45 test
Creating cache test00000-12...
.mycache: found 2 matching files
No URL provided, cache will be not uploaded to shared cache server. Cache will be stored only locally.
Created cache
Job succeeded