a pool of locks (modeling semaphores)
Allows you to lock environments, pipeline flow, or other entities which have to be interacted with in a serial manner.
This resource is backed by a Git repository, so the configuration is largely the same as the git-resource.
.
├── aws
│ ├── claimed
│ │ ├── .gitkeep
│ │ └── env-2
│ └── unclaimed
│ ├── .gitkeep
│ └── env-1
├── ping-pong-tables
│ ├── claimed
│ │ └── .gitkeep
│ └── unclaimed
│ ├── .gitkeep
│ └── north-table
└── vsphere
├── claimed
│ ├── .gitkeep
│ └── f3cb3823-a45a-49e8-ab41-e43268494205
└── unclaimed
├── .gitkeep
└── 83ed9977-3a10-4c49-a818-2d7a37693da7
This structure represents 3 pools of locks, aws
, ping-pong-tables
, and
vsphere
. The .gitkeep
files are required to keep the unclaimed
and
claimed
directories track-able by Git if there are no files in them.
You will need to mirror this structure in your own lock repository. In other words, initialize an empty repository
and create one directory in the root of the repository for each pool of locks (e.g. aws
). Inside of each lock pool directory, create one directory
named claimed
and one directory named unclaimed
. Inside each claimed
and unclaimed
directory, create an empty
filed named .gitkeep
. Finally, create individual locks by making an empty file inside of the unclaimed
directory
(assuming you want your lock to be unclaimed by default) with the desired name of the lock (e.g. env-1
).
-
uri
: Required. The location of the repository. -
branch
: Required. The branch to track. -
pool
: Required. The logical name of your pool of things to lock. -
private_key
: Optional. Private key to use when pulling/pushing. Ensure it does not require a password. Example:private_key: | -----BEGIN RSA PRIVATE KEY----- MIIEowIBAAKCAQEAtCS10/f7W7lkQaSgD/mVeaSOvSF9ql4hf/zfMwfVGgHWjj+W <Lots more text> DWiJL+OFeg9kawcUL6hQ8JeXPhlImG6RTUffma9+iGQyyBMCGd1l -----END RSA PRIVATE KEY-----
-
username
: Optional. Username for HTTP(S) auth when pulling/pushing. This is needed when only HTTP/HTTPS protocol for git is available (which does not support private key auth) and auth is required. -
password
: Optional. Password for HTTP(S) auth when pulling/pushing. -
retry_delay
: Optional. If specified, dictates how long to wait until retrying to acquire a lock or release a lock. The default is 10 seconds. Valid values:60s
,90m
,1h
. -
diff_filter
: Optional. If specified, changes the behavior of check. This is an advanced feature of git, refer to git-log for more information. The default behavior is checking on every commit.
The repository is cloned (or pulled if already present), and any commits made to the specified pool from the given version on are returned.
If no version is given, the ref for HEAD
is returned. The behavior can be altered by defining diff_filter
in source
configuration.
Here is a mapping between diff-filter
and check behavior:
Diff-filter | Check Behavior |
---|---|
A | add, add_claimed |
R | acquire, claim, release |
D | remove |
M | update |
For example, if diff_filter: AM
is specificed, it will only check when a resource is added to the pool or the existing resource is updated.
Outputs 2 files:
-
metadata
: Contains the contents of whatever was in your lock file. This is useful for environment configuration settings. -
name
: Contains the name of lock that was acquired.
Performs one of the following actions to change the state of the pool.
One of the following is required.
-
acquire
: If true, we will attempt to move a randomly chosen lock from the pool's unclaimed directory to the claimed directory. Acquiring will retry until a lock becomes available. -
claim
: If set, the specified lock from the pool will be acquired, rather than a random one (as inacquire
). Likeacquire
, claiming will retry until the specific lock becomes available. -
release
: If set, we will release the lock by moving it from claimed to unclaimed. The value is the path of the lock to release (a directory containingname
andmetadata
), which typically is just the step that provided the lock (either aget
to pass one along or aput
to acquire).Note: the lock must be available in your job before you can release it. In other words, a
get
step to fetch metadata about the lock is necessary before aput
step can release the lock. -
add
: If set, we will add a new lock to the pool in the unclaimed state. The value is the path to a directory containing the filesname
andmetadata
which should contain the name of your new lock and the contents you would like in the lock, respectively. -
add_claimed
: Exactly the same as theadd
param, but adds a lock to the pool in the claimed state. -
remove
: If set, we will remove the given lock from the pool. The value is the same asrelease
. This can be used for e.g. tearing down an environment, or moving a lock between pools by usingadd
with a different pool in a second step. -
update
: If set, we will update an existing lock in the pool.- If the existing lock is in the unclaimed state we will update it with the
contents of the
metadata
file. - If no such lock is present in either the claimed or unclaimed state we add a new lock to the pool in the unclaimed state.
- If the lock is in the claimed state we will wait for it to be unclaimed and proceed to update it as above.
The value is the path to a directory containing the files
name
andmetadata
which should contain the name of your new lock and the contents you would like in the lock, respectively. - If the existing lock is in the unclaimed state we will update it with the
contents of the
The following example pipeline models acquiring, passing through, and releasing a lock based on the example git repository structure:
resources:
- name: aws-environments
type: pool
source:
uri: [email protected]:concourse/locks.git
branch: master
pool: aws
private_key: |
-----BEGIN RSA PRIVATE KEY-----
MIIEowIBAAKCAQEAtCS10/f7W7lkQaSgD/mVeaSOvSF9ql4hf/zfMwfVGgHWjj+W
<Lots more text>
DWiJL+OFeg9kawcUL6hQ8JeXPhlImG6RTUffma9+iGQyyBMCGd1l
-----END RSA PRIVATE KEY-----
jobs:
- name: deploy-aws
plan:
- put: aws-environments
params: {acquire: true}
- task: deploy-aws
file: my-scripts/deploy-aws.yml
- name: test-aws
plan:
- get: aws-environments
passed: [deploy-aws]
- task: test-aws
file: my-scripts/test-aws.yml
- put: aws-environments
params: {release: aws-environments}
The parameter for release
is the name of the step whose lock to release.
Normally this is just the same as the name of the resource, but if you have
custom names for put
(for example if you need to acquire multiple instances
of the same pool), you would put that name instead. For example:
- name: test-multi-aws
plan:
- put: environment-1
resource: aws-environments
params: {acquire: true}
- put: environment-2
resource: aws-environments
params: {acquire: true}
- task: test-multi-aws
file: my-scripts/test-multi-aws.yml
- put: aws-environments
params: {release: environment-1}
- put: aws-environments
params: {release: environment-2}
- golang is required - version 1.9.x is tested; earlier versions may also work.
- docker is required - version 17.06.x is tested; earlier versions may also work.
The tests have been embedded with the Dockerfile
; ensuring that the testing
environment is consistent across any docker
enabled platform. When the docker
image builds, the test are run inside the docker container, on failure they
will stop the build.
Run the tests with the following command:
docker build -t pool-resource .
Please make all pull requests to the master
branch and ensure tests pass
locally.