Adds support of sessionId for External-Job-Monitor

[Abhishekkr3003]

I was using the External-Job-Monitor plugin and following this Doc, but I was getting 403 responses like this:

On looking into the code, found a bug:
GET request to fetch crumb before POST request for postBuildResult has an extra ', due to which GET request was giving a non-2XX response, and crumb fields were not getting enriched.

Furthermore, I was still getting 403 responses, and then I found this change. which mentioned:

CSRF tokens (crumbs) are now only valid for the web session

So, to make things work, I added the support for sessionId returned in the GET call (to fetch crumb) to be sent in the POST call for postBuildResult.

And then getting the expected results:

To summarize, this PR has the following two changes:

1. Fixes bug in GET call of crumb
2. Adds sessionId support

Testing done

Testing is done as mentioned above.

Proposed changelog entries

• Support Session ID for External Job Monitor to prevent HTTP 503 response.

Proposed upgrade guidelines

N/A

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@mention

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[mawinter69]

According to https://issues.jenkins.io/browse/JENKINS-70684 this class is probably obsolete. Maybe the documentation needs to be updated in the plugin to no longer point to using things from core

[Abhishekkr3003]

@mawinter69 I think SetExternalBuildResultCommand requires us to store the logs and send them via SSH to the Jenkins Host as mentioned in the doc. But Hudon Main wraps our command, keeps the log, and sends via HTTP to Jenkins, which gives quite a bit of flexibility while using the External-Job-Monitor plugin. So, keeping this class or at least this functionality is better.

[Kevin-CB]

I tested your PR locally, it looks fine from a security perspective!

[NotMyFault]

/label ready-for-merge

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[jglick]

Hudon Main wraps our command, keeps the log, and sends via HTTP to Jenkins

Fine but as mentioned in Jira please instead move all of this functionality into some utility in the plugin, so we can delete the class from core. It does not belong here and should not be touched.

[daniel-beck]

@jglick It looks like you may have an opinion on #9023

[jglick]

Indeed. BTW I think all the logic here to retrieve a crumb ought to be deleted anyway, as it should only be needed if you are using a password rather than an API token.