Problem

Some users observe the following error message when initially running jobs:

UnknownKey: No such environment variable: COMPUTERNAME

This problem can occur if example workflows have been used from JS7 - Download.

As a result some jobs of the example workflows fail with the above error message.

Analysis

The error message indicates that an environment variable with the name COMPUTERNAME is used in a job. However this environment variable does not exist.

• The reason is with the JS7 - Job Resources from the archive Defaults.zip that is offered from JS7 - Download. After import this archive is extracted to a JOC Cockpit folder with the name Defaults and a job resource with the name Default. Find details from JS7 - Job Environment Variables.

• The Default job resource includes an argument with the name js7AgentHostname and an environment variable with the name JS7_AGENT_HOSTNAME. By default the argument is assigned this value:

  js7AgentHostname = env('HOSTNAME', env('COMPUTERNAME'))

• The expression first makes use of a HOSTNAME environment variable (available for most Unix systems) and if this does not exist uses the COMPUTERNAME environment variable (available for Windows systems). Therefore running a job that makes use of the Default job resource on a Unix OS that does not provide the HOSTNAME environment variable causes the error.

The assignment of the js7AgentHostname argument is performed in the Configuration view for Job Resources like this:

Solution

Modify the value of the js7AgentHostname argument like this:

js7AgentHostname = env('HOSTNAME', env('COMPUTERNAME', ""))

Explanation:

• The env() function makes use of two arguments: the first argument specifies an environment variable, the second argument specifies a default value should the environment variable not exist.
• Adding an empty default value - specified by two double quotes - as provided from the above example resolves the problem.
• To apply changes deploy the job resource after modification.