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You can use locks to prevent a job start, starting while another job is running. You can find the information about looks locks at http://www.sos-berlin.com/doc/en/scheduler.doc/lock.xml

Locks are defined in files in the hot folder (live). The name of the file is Lock file names follow the convention:

• the name of the lock followed by .lock.xml.
  E.g. lockSample.lock.xml

Using To use locks, you have to:

1. declare a lock
2. assign the lock to the involved required jobs

Example

To delclare the lock apply a configuration such asA typical lock declaration would be:

    <locks>
        <lock name="lockSample"/>
    </locks>

To assign the lock to your jobs use:

 <?xml version="1.0" encoding="ISO-8859-1"?>
 <job order="yes"
     stop_on_error="no">
    <lock.use lock="lockSample"
              exclusive="yes"/>
    <script language="shell">
        <![CDATA[
 echo "here is the job jobsSample_1"
 echo "I'm not running in parallel with job jobsSample_2"
 ping -n 60 localhost
         ]]>
    </script>
 </job>

...

 <?xml version="1.0" encoding="ISO-8859-1"?>
 <job_chain>
    <job_chain_node state="100"
                    job="jobsSample_2"
                    next_state="success"
                    error_state="error"/>
    <job_chain_node state="success"/>
    <job_chain_node state="error"/>
 </job_chain>

Scope of locks

• Where to store locksare lock files saved?
  
  • Locks are stored directly in the live folder or any sub-folders.
• How to do you reference locks in jobs?
  • Locks are identified by their path that :
    • this is made up of the folder where the lock is stored and of the name of the lock.
  • Locks that are located in the same folder as the job can address be addressed using the lock by using its 's name (omitting the folder).
• Example:
  • Lock Location
    • Folder live/project_a contains a set of jobs and a lock named my_lock_a
    • Folder live/project_b contains a set of jobs and a lock named my_lock_b
  • Lock Usage
    • Job job_a from folder the folder named project_a can reference the lock from its folder by using e.g.using for example:
      • <lock.use name="my_lock_a" exclusive="true"/> 
    • Job job_b from folder project_b can be configured accordingly to use its local lock in a similar manner. 
    • Should the it be necessary to prevent jobs job_a and job_b be prevented to run from runnig in parallel then they have to use a common lock. This is achieved by referencing the same a common lock, e.g. job job_b would could use a reference to my_lock_a from the folder project_a like this:
      • <lock.use name="/project_a/my_lock_a" exlcusive="yes"/>
    • Caveat: It is possible to use the same lock name in different folders . This represents to represent different locks. Jobs using relative addressing of locks by using the lock's name lock addressing (i.e. just the locks' name) and omitting the folder name would reference the lock in their local folder. Consider to use absolute adressing of locks using absolute lock addressing if you want jobs from different folders to make use of the same lock. 
    • Hint: Locks that are located directly in the live folder can be addressed with a leading slash as follows:
      • <lock.use name="/my_global_lock" exclusive="yes"/>