Lockable Resources

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This plugin allows defining lockable resources (such as printers, phones, computers, etc.) that can be used by builds. If a build requires a resource which is already locked, it will wait for the resource to be free.

Usage

Adding lockable resources

  1. In Manage Jenkins > Configure System go to Lockable Resources Manager
  2. Select Add Lockable Resource

Each lockable resource has the following properties:

  • Name - A mandatory name (not containing spaces!) for this particular resource, i.e. DK_Printer_ColorA3_2342
  • Description - Optional verbose description of this particular resource, i.e. Printers in the Danish Office
  • Labels - Optional space-delimited list of Labels (A label can not containing spaces) used to identify a pool of resources. i.e. DK_Printers_Office Country:DK device:printer, DK_Printer_Production, DK_Printer_Engineering
  • Reserved by - Optional reserved / locked cause. If non-empty, the resource will be unavailable for jobs. i.e. All printers are currently not available due to maintenance. This option is still possible, but we recommend to use the page <jenkinsRootUrl>/lockable-resources/

A resource is always the one thing that is locked (or free or reserved). It exists once and has an unique name (if we take the hardware example, this may be office_printer_14). Every resource can have multiple labels (the printer could be labeled dot-matrix-printer, in-office-printer, a4-printer, etc.). All resources with the same label form a "pool", so if you try to lock an a4-printer, one of the resources with the label a4-printer will be locked when it is available. If all resources with the label a4-printer are in use, your job waits until one is available. This is similar to nodes and node labels.

Using a resource in a freestyle job

When configuring the job, select This build requires lockable resources. Please see the help item for each field for details.

Using a resource in a pipeline job

When the lock step is used in a Pipeline, if the resource to be locked isn't already defined in the Jenkins global configuration, an ephemeral resource is used: These resources only exist as long as any running build is referencing them.

Examples:

Acquire lock

echo 'Starting'
lock('my-resource-name') {
  echo 'Do something here that requires unique access to the resource'
  // any other build will wait until the one locking the resource leaves this block
}
echo 'Finish'

Take first position in queue

lock(resource: 'staging-server', inversePrecedence: true) {
    node {
        servers.deploy 'staging'
    }
    input message: "Does ${jettyUrl}staging/ look good?"
}

Resolve a variable configured with the resource name

lock(label: 'some_resource', variable: 'LOCKED_RESOURCE') {
  echo env.LOCKED_RESOURCE
}

When multiple locks are acquired, each will be assigned to a numbered variable:

lock(label: 'some_resource', variable: 'LOCKED_RESOURCE', quantity: 2) {
  // comma separated names of all acquired locks
  echo env.LOCKED_RESOURCE

  // first lock
  echo env.LOCKED_RESOURCE0

  // second lock
  echo env.LOCKED_RESOURCE1
}

Skip executing the block if there is a queue

lock(resource: 'some_resource', skipIfLocked: true) {
  echo 'Do something now or never!'
}

Detailed documentation can be found as part of the Pipeline Steps documentation.

Multiple resource lock

lock(label: 'label1', extra: [[resource: 'resource1']]) {
	echo 'Do something now or never!'
}
echo 'Finish'"
lock(
  variable: 'var',
  extra: [
    [resource: 'resource4'],
    [resource: 'resource2'],
    [label: 'label1', quantity: 2]
  ]
) {
  def lockedResources = env.var.split(',').sort()
  echo "Resources locked: ${lockedResources}"
}
echo 'Finish'

More examples are here.

Configuration as Code

This plugin can be configured via Configuration-as-Code.

Example configuration

unclassified:
  lockableResourcesManager:
    declaredResources:
      - name: "S7_1200_1"
        description: "S7 PLC model 1200"
        labels: "plc:S7 model:1200"
        reservedBy: "Reserved due maintenance window"
      - name: "S7_1200_2"
        labels: "plc:S7 model:1200"

Properties description, labels and reservedBy are optional.

lockable-resources overview

The page <jenkinsRootUrl>/lockable-resources/ provides an overview over all resources and actions to change resource status.

Name Permission Description
Reserve RESERVE Reserves an available resource for currently logged user indefinitely (until that person, or some explicit scripted action, decides to release the resource).
Unreserve RESERVE Un-reserves a resource that may be reserved by some person already. The user can unreserve only own resource. Administrator can unreserve any resource.
Unlock UNLOCK Unlocks a resource that may be or not be locked by some job (or reserved by some user) already.
Steal lock STEAL Reserves a resource that may be or not be locked by some job (or reserved by some user) already. Giving it away to currently logged user indefinitely (until that person, or some explicit scripted action, later decides to release the resource).
Reassign STEAL Reserves a resource that may be or not be reserved by some person already. Giving it away to currently logged user indefinitely (until that person, or some explicit scripted action, decides to release the resource).
Reset UNLOCK Reset a resource that may be reserved, locked or queued.
Note RESERVE Add or edit resource note.

Changelog

Report an Issue

Please report issues and enhancements through the Jenkins issue tracker in GitHub

Contributing

Contributions are welcome, please refer to the separate CONTRIBUTING document for details on how to proceed! Join Gitter channel to discuss your ideas with the community.

License

All source code is licensed under the MIT license. See LICENSE