Read the event log rather than whatever logs the bmc offers

The redfish event log was taken from every log service the manager
advertises, whatever those turned out to be.  On a bmc that keeps its
systemd journal there, nodeeventlog answered with a thousand lines of
kernel probe failures and daemon chatter, and the log the user asked for
was never read at all, because this implementation keeps it under the
system.  Clearing was worse: of the services it did find, the ones with a
clear action were the dumps, so a clear destroyed diagnostic data, left
the event log untouched, and reported success.

Judge a log service before reading it.  A service whose id or name says
journal, dump, post code, host logger or crash is not an event log, and
both reading and clearing skip it, so a clear can no longer take out
something that was never asked for.

If that leaves the manager with no event log at all, look under the
system, where such an implementation keeps it.  Only then: a bmc that has
one under the manager is served exactly as before, from the same requests,
so this cannot change what an implementation that already worked reports.

The list of services was also being extended in place, and it belongs to
whatever the url cache is holding, so an extra log added by an oem handler
accumulated on every call within the cache window.

confluent_server/aiohmi/redfish/oem/generic.py

@@ -549,6 +549,23 @@ class OEMHandler(object):
                     }
                     yield certdesc
 
+    # A log service whose id or name says one of these is not an event log:
+    # the bmc's own systemd journal, dumps of several kinds, and firmware boot
+    # progress.  Reading them buries the events that were asked for, and
+    # clearing them destroys diagnostic data that has nothing to do with the
+    # event log.
+    noneventlogwords = ('journal', 'dump', 'postcode', 'hostlogger', 'crash')
+
+    @classmethod
+    def is_event_log(cls, loginfo):
+        """Say whether a log service holds events rather than something else"""
+        identity = '{0} {1}'.format(loginfo.get('Id', ''),
+                                    loginfo.get('Name', '')).lower()
+        for word in cls.noneventlogwords:
+            if word in identity:
+                return False
+        return True
+
     async def get_event_log(self, clear=False, fishclient=None, extraurls=[]):
         bmcinfo = await self._do_web_request(await fishclient.get_bmcurl())
         lsurl = bmcinfo.get('LogServices', {}).get('@odata.id', None)
@@ -566,10 +583,41 @@ class OEMHandler(object):
                 correction = now - currtime
             except TypeError:
                 correction = now - currtime.replace(tzinfo=utz)
-        lurls = (await self._do_web_request(lsurl)).get('Members', [])
-        lurls.extend(extraurls)
+
+        async def eventlogurls(lscollection):
+            """The log services in a collection that hold events"""
+            found = []
+            lscol = await self._do_web_request(lscollection)
+            for member in lscol.get('Members', []):
+                candidate = member['@odata.id']
+                try:
+                    loginfo = await self._do_web_request(candidate,
+                                                         cache=(not clear))
+                except Exception:
+                    # leave it in, so the loop below reports it as unreadable
+                    found.append(candidate)
+                    continue
+                if self.is_event_log(loginfo):
+                    found.append(candidate)
+            return found
+
+        lurls = await eventlogurls(lsurl)
+        if not lurls:
+            # Some implementations keep no event log under the manager and put
+            # it under the system instead, so fall back to looking there rather
+            # than answering with nothing at all.
+            for sysurl in self._allsysurls:
+                currsysinfo = await self._do_web_request(sysurl)
+                syslsurl = currsysinfo.get('LogServices', {}).get(
+                    '@odata.id', None)
+                if syslsurl:
+                    lurls.extend(await eventlogurls(syslsurl))
+        lurls.extend([x['@odata.id'] for x in extraurls])
+        seenurls = set()
         for lurl in lurls:
-            lurl = lurl['@odata.id']
+            if lurl in seenurls:
+                continue
+            seenurls.add(lurl)
             try:
                 loginfo = await self._do_web_request(lurl, cache=(not clear))
             except Exception:
@@ -580,7 +628,6 @@ class OEMHandler(object):
                 record['timestamp'] = datetime.now().strftime('%Y-%m-%dT%H:%M:%S')
                 yield record
                 continue
-            loginfo = await self._do_web_request(lurl, cache=(not clear))
             entriesurl = loginfo.get('Entries', {}).get('@odata.id', None)
             if not entriesurl:
                 continue