worker: Log error in remote_getWorkerInfo instead of crashing

Worker lists and reads all file in WORKER/info folder in functin remote_getWorkerInfo. To prevent it from crashing when it encounteres file that can not be decoded we now only report this error to log and continue.

Fixes buildbot#3585
Fixes buildbot#4758
Fixes buildbot#6932

newsfragments/get-worker-info.bugfix

@@ -0,0 +1 @@
+Fix worker not connecting error when there are files in WORKER/info folder that can not be decoded. (:issue:`3585`) (:issue:`4758`) (:issue:`6932`)

worker/buildbot_worker/base.py

@@ -25,12 +25,14 @@
 from twisted.application import service
 from twisted.internet import defer
 from twisted.internet import reactor
+from twisted.python import failure
 from twisted.python import log
 from twisted.spread import pb
 
 import buildbot_worker
 from buildbot_worker.commands import base
 from buildbot_worker.commands import registry
+from buildbot_worker.compat import bytes2unicode
 from buildbot_worker.util import buffer_manager
 from buildbot_worker.util import lineboundaries
 
@@ -218,7 +220,11 @@ def remote_getWorkerInfo(self):
                 filename = os.path.join(basedir, f)
                 if os.path.isfile(filename):
                     with open(filename, "r") as fin:
-                        files[f] = fin.read()
+                        try:
+                            files[f] = bytes2unicode(fin.read())
+                        except UnicodeDecodeError:
+                            log.err(failure.Failure(),
+                                    'error while reading file: %s' % (filename))
 
         self._read_os_release(self.os_release_file, files)
 

worker/buildbot_worker/test/unit/test_bot.py

@@ -127,6 +127,41 @@ def test_getWorkerInfo_nodir(self):
             ['environ', 'system', 'numcpus', 'basedir', 'worker_commands', 'version',
              'delete_leftover_dirs']))
 
+    @defer.inlineCallbacks
+    def test_getWorkerInfo_decode_error(self):
+        infodir = os.path.join(self.basedir, "info")
+        os.makedirs(infodir)
+        with open(os.path.join(infodir, "admin"), "w") as f:
+            f.write("testy!")
+        with open(os.path.join(infodir, "foo"), "w") as f:
+            f.write("bar")
+        with open(os.path.join(infodir, "environ"), "w") as f:
+            f.write("something else")
+        # This will not be part of worker info
+        with open(os.path.join(infodir, "binary"), "wb") as f:
+            f.write(b"\x90")
+
+        # patch the log.err, otherwise trial will think something *actually*
+        # failed
+        self.patch(log, "err", lambda f, x: None)
+
+        info = yield self.bot.callRemote("getWorkerInfo")
+
+        # remove any os_ fields as they are dependent on the test environment
+        info = {k: v for k, v in info.items() if not k.startswith("os_")}
+
+        self.assertEqual(info, {
+            "admin": 'testy!',
+            "foo": 'bar',
+            "environ": os.environ,
+            "system": os.name,
+            "basedir": self.basedir,
+            "worker_commands": self.real_bot.remote_getCommands(),
+            "version": self.real_bot.remote_getVersion(),
+            "numcpus": multiprocessing.cpu_count(),
+            "delete_leftover_dirs": False
+            })
+
     def test_shutdown(self):
         d1 = defer.Deferred()
         self.patch(reactor, "stop", lambda: d1.callback(None))