Job Channel Steps¶
The Start channels, Stop channels, Pause channels, Resume channels and Restart channels steps change the state of channels at each site. Each channel is changed on its own, through the same start, stop, pause, resume and restart operations the console uses, as the preparer's Hub user.
Which Channels a Step Acts On¶
By default, a channel step acts on the channels the job's import affected at that site: the channels the import created or saved, whether or not the file changed them, and those that use a published function, published mapping or certificate it created or changed. The import saves every object in its file that matches one at the site, but a published function, published mapping or certificate counts as changed only when what it holds differs from before the import, so channels that use one the file left as it was are not acted on. A step can name its channels instead, in Channels, one zone/channel per line. See Job Steps.
In a step's result, a channel in a zone that the person's site role may not view is shown as "a channel in a zone you cannot see".
What Each Step Changes¶
A step changes only the channels in a state it applies to. A channel in any other state is left as it is, and does not fail the step.
| Step | Changes channels that are | Leaves alone channels that are |
|---|---|---|
| Start channels | Stopped or errored | Running, paused or stopping |
| Stop channels | Running, paused or errored | Stopped or stopping |
| Pause channels | Running | Stopped, paused, errored or stopping |
| Resume channels | Paused | Stopped, running, errored or stopping |
| Restart channels | Running or errored | Stopped, paused or stopping |
The step also leaves alone:
- A disabled channel.
- A channel in a zone where the preparer's Hub user does not have the manage right. The user's rights come from the role the site's Role Map gives the preparer's Hub role.
Channels at persistence level 0
Before it stops a channel at persistence level 0, the console warns that stopping it while messages are being processed may lose them. A Stop channels step gives no such warning. Where such a channel may be among those a step would stop, name the channels the step acts on in Channels.
Developer Licenses¶
A site with a developer license does not start channels for the Hub. At such a site, a start, resume or restart step skips every channel it would have changed, and writes a warning to each channel's log saying the Hub request was ignored because a developer license is installed. The Management API and the MCP skip the same way.
The Hub skips such sites before they begin: a job that has a start, resume or restart step does not run at a site that reported a developer license, and shows "not ready, not run (developer license)" for it. The site's own check covers a license installed after the site last reported its settings. See Job Site Outcomes.
When the Step Fails¶
A channel step fails at a site when:
- A channel the step names is not at that site.
- Changing a channel fails, for example a channel that does not start.
A channel that is left alone, or skipped for a developer license, does not fail the step. A failed step ends that site's part of the job; see Running a Job.
On a Clustered Site¶
The step runs on the node of the site that holds its connection to the Hub, and reads each channel's state as that node sees it.