[JENKINS-61193] Export no_proxy hosts when using HTTP proxy

[Gyanesha]

JENKINS-61193 - Export no_proxy hosts when using HTTP proxy

I have added an ArrayList containing all the hosts which don't need any proxy. Then at the time of setting environment variables for proxy I have also set the hosts(e.g. 169.254.169.254) which will not require any proxy.

Checklist

Put an x in the boxes that apply. You can also fill these out after creating the PR. If you're unsure about any of them, don't hesitate to ask. This is simply a reminder of what we are going to look for before merging your code.

• I have read the CONTRIBUTING doc
• I have referenced the Jira issue related to my changes in one or more commit messages
• I have added tests that verify my changes
• Unit tests pass locally with my changes
• I have added documentation as necessary
• No Javadoc warnings were introduced with my changes
• No spotbugs warnings were introduced with my changes
• I have interactively tested my changes

Types of changes

What types of changes does your code introduce? Put an x in the boxes that apply

• Infrastructure change (non-breaking change which updates dependencies or improves infrastructure)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Further comments

If this is a relatively large or complex change, start the discussion by explaining why you chose the solution you did and what alternatives you considered.

[codingtim]

You're not supposed to make the list of non proxy hosts hard coded, these should be retrieved from the configuration on the proxy object.
env.put("no_proxy", getNoProxyHosts());
with implemeation of method:

private String getNoProxyHosts() {
   String noProxyHost = proxy.noProxyHost;
   List<String> noProxyHosts = Lists.newArrayList(Arrays.asList(noProxyHost.split("[ \t\n,|]+")));
   return String.join(",", noProxyHosts);
}

The proxy object is of type hudson.ProxyConfiguration. This class already has some utility methods to retrieve the no proxy hosts as a list of Patterns but that is not usable here.

[MarkEWaite]

Must use the values of NO_PROXY as provided by the Jenkins interface. Must have automated tests that show the NO_PROXY setting is honored.

[Gyanesha]

Thanks @codingtim for the help. @MarkEWaite can you tell me whether I should make automated test for checking if the no proxy hosts have been added as no_proxy in the environment variable or something else.

[Gyanesha]

How will I check whether the NO_PROXY setting is being honored ? Do I have to make some http request to no_proxy host ?

[MarkEWaite]

How will I check whether the NO_PROXY setting is being honored ? Do I have to make some http request to no_proxy host ?

I should have been more clear when I said "NO_PROXY is honored". In this case, I think the reasonable effort task is to place a NO_PROXY into the environment and then confirm that the expected value is in the environment.

As far as I understand it, there are many different ways to configure proxies and each has its own set of common mistakes and challenges. We can't test more than the most basic "is it set" functionality in the test automation.

[Gyanesha]

I wanted to ask one more question, like why we are not putting the proxy settings in global environment (EnvVar) variable, rather than local env (EnvVar) variable. In the function launchCommandWithCredentials(), we are overwriting env with itself, which in the very begining of the function represented global environment.
env = new EnvVars(env);
Don't we want to reflect the changes in our setting to the global variable.

[Gyanesha]

I have made the required changes in new commit.