Listen on loopback interface by default in debug mode

[daniel-beck]

Local development setups usually don't need to listen on all interfaces, so restrict to localhost by default when running mvn jetty:run.

Apparently host is the Jetty terminology for the listen address, so use that for the property.
I didn't want to think about IPv4/IPv6, so use localhost instead of e.g. 127.0.0.1. JenkinsRule uses localhost as well.

Restore previous behavior by setting -Dhost=0.0.0.0 on the command line.

Corresponding PR in Maven HPI Plugin at jenkinsci/maven-hpi-plugin#169.

Proposed changelog entries

Too minor? Unsure.

Proposed upgrade guidelines

N/A

Submitter checklist

• [n/a] JIRA issue is well described
• [n/a] Changelog entries and upgrade guidelines are appropriate for the audience affected by the change (users or developer, depending on the change). Examples
  • Fill-in the Proposed changelog entries section only if there are breaking changes or other changes which may require extra steps from users during the upgrade
• [n/a] Appropriate autotests or explanation to why this change has no tests
• [n/a] For dependency updates: links to external changelogs and, if possible, full diffs

Desired reviewers

@mention

Maintainer checklist

Before the changes are marked as ready-for-merge:

• There are at least 2 approvals for the pull request and no outstanding requests for change
• Conversations in the pull request are over OR it is explicit that a reviewer does not block the change
• Changelog entries in the PR title and/or Proposed changelog entries are correct
• Proper changelog labels are set so that the changelog can be generated automatically
• If the change needs additional upgrade steps from users, upgrade-guide-needed label is set and there is a Proposed upgrade guidelines section in the PR title. (example)
• If it would make sense to backport the change to LTS, a JIRA issue should exist and be labeled as lts-candidate

[oleg-nenashev]

I plan to merge it tomorrow if no negative feedback

[Wadeck]

Too minor? Unsure.

I am more in favor of having a line on the changelog. It could be useful to developer using this "feature" in their environment to find when it was added and especially the workaround.

Otherwise the PRs themselves seem fine 👍

[oleg-nenashev]

Since all of us agree in principle, 🚢 🇮🇹 . We can discuss the changelog in the background

[timja]

This broke my local developer setup,

macOS Catalina

Errors were:
This page isn’t workinglocalhost didn’t send any data.
ERR_EMPTY_RESPONSE

and
Sometimes:
ERR_SOCKET_NOT_CONNECTED

I've found that it will works for me if I access jenkins via:
http://127.0.0.1:8080/jenkins

I was previously using:
http://localhost:8080/jenkins

[timja]

-Dhost=0.0.0.0 doesn't revert to the previous behaviour, I still can't access it with localhost

[timja]

Hmm so I was using intellij and it seems for maven properties you don't use VM options, you use the properties section below it, that worked, still not a fix, but at least I can workaround it.

[timja]

Grrr, this was my antivirus, Eset Endpoint security, they think they're so cool, let's block port 8080 on localhost,
WTF
webpack/webpack-dev-server#2272 (comment)