4.11.11.5 BuildStep URLs

Each BuildStep has a collection of “links”. Like its collection of LogFiles, each link has a name and a target URL. The web status page creates HREFs for each link in the same box as it does for LogFiles, except that the target of the link is the external URL instead of an internal link to a page that shows the contents of the LogFile.

These external links can be used to point at build information hosted on other servers. For example, the test process might produce an intricate description of which tests passed and failed, or some sort of code coverage data in HTML form, or a PNG or GIF image with a graph of memory usage over time. The external link can provide an easy way for users to navigate from the buildbot's status page to these external web sites or file servers. Note that the step itself is responsible for insuring that there will be a document available at the given URL (perhaps by using scp to copy the HTML output to a ~/public_html/ directory on a remote web server). Calling addURL does not magically populate a web server.

To set one of these links, the BuildStep should call the addURL method with the name of the link and the target URL. Multiple URLs can be set.

In this example, we assume that the make test command causes a collection of HTML files to be created and put somewhere on the coverage.example.org web server, in a filename that incorporates the build number.

     class TestWithCodeCoverage(BuildStep):
         command = ["make", "test",
                    WithProperties("buildnum=%s", "buildnumber")]
     
         def createSummary(self, log):
             buildnumber = self.getProperty("buildnumber")
             url = "http://coverage.example.org/builds/%s.html" % buildnumber
             self.addURL("coverage", url)

You might also want to extract the URL from some special message output by the build process itself:

     class TestWithCodeCoverage(BuildStep):
         command = ["make", "test",
                    WithProperties("buildnum=%s", "buildnumber")]
     
         def createSummary(self, log):
             output = StringIO(log.getText())
             for line in output.readlines():
                 if line.startswith("coverage-url:"):
                     url = line[len("coverage-url:"):].strip()
                     self.addURL("coverage", url)
                     return

Note that a build process which emits both stdout and stderr might cause this line to be split or interleaved between other lines. It might be necessary to restrict the getText() call to only stdout with something like this:

             output = StringIO("".join([c[1]
                                        for c in log.getChunks()
                                        if c[0] == LOG_CHANNEL_STDOUT]))

Of course if the build is run under a PTY, then stdout and stderr will be merged before the buildbot ever sees them, so such interleaving will be unavoidable.