amari.xlog: Add support for arbitrary query options

Before this patch we were supporting only boolean option flags - with, for
example, stats[rf] meaning stats query with {"rf": True} arguments. Now we add
support for arbitrary types, so that it is possible to specify e.g. integer or
string query options, as well as some boolean flag set to false.

This should be good for generality.

For backward compatibility the old way to implicitly specify "on" flags is
continued to be supported.

amari/xlog.py

@@ -85,18 +85,24 @@ log = logging.getLogger('xlte.amari.xlog')
 # For example stats[rf]/10s.
 class LogSpec:
     # .query        e.g. 'stats'
-    # .optv         [] with flags to send with query
+    # .opts         {} opt -> value to send with query
     # .period       how often to issue the query (seconds)
 
     DEFAULT_PERIOD = 60
 
-    def __init__(spec, query, optv, period):
+    def __init__(spec, query, opts, period):
         spec.query  = query
-        spec.optv   = optv
+        spec.opts   = opts
         spec.period = period
 
     def __str__(spec):
-        return "%s[%s]/%gs" % (spec.query, ','.join(spec.optv), spec.period)
+        optv = []
+        for opt, val in spec.opts.items():
+            if val is True:
+                optv.append(opt)
+            else:
+                optv.append('%s=%s' % (opt, json.dumps(val)))
+        return "%s[%s]/%gs" % (spec.query, ','.join(optv), spec.period)
 
     # LogSpec.parse parses text into LogSpec.
     @staticmethod
@@ -104,7 +110,7 @@ class LogSpec:
         def bad(reason):
             raise ValueError("invalid logspec %s: %s" % (qq(text), reason))
 
-        optv = []
+        opts = {}
         period = LogSpec.DEFAULT_PERIOD
         query = text
         _ = query.rfind('/')
@@ -126,13 +132,19 @@ class LogSpec:
             if _ == -1:
                 bad("missing closing ]")
             optv = tail[1:_].split(',')
+            for opt in optv:
+                val = True
+                if '=' in opt:
+                    opt, val = opt.split('=', 1)
+                    val = json.loads(val)
+                opts[opt] = val
             tail = tail[_+1:]
 
         for c in '[]/ ':
             if c in query:
                 bad("invalid query")
 
-        return LogSpec(query, optv, period)
+        return LogSpec(query, opts, period)
 
 
 # IWriter represents output to where xlog writes its data.
@@ -166,10 +178,10 @@ def xlog(ctx, wsuri, w: IWriter, logspecv):
     logspecv = logspecv[:]  # keep caller's intact
     if lsync is None:
         isync = 0
-        lsync = LogSpec("meta.sync", [], pmax*10)
+        lsync = LogSpec("meta.sync", {}, pmax*10)
         logspecv.insert(0, lsync)
     if lconfig_get is None:
-        logspecv.insert(isync+1, LogSpec("config_get", [], lsync.period))
+        logspecv.insert(isync+1, LogSpec("config_get", {}, lsync.period))
 
     # verify that sync will come at least every LOS_window records
     ns = 0
@@ -354,10 +366,6 @@ class _XLogger:
             logspec = xl.logspecv[imin]
             tnextv[imin] += logspec.period
 
-            opts = {}
-            for opt in logspec.optv:
-                opts[opt] = True
-
             # issue queries with planned schedule
             # TODO detect time overruns and correct schedule correspondingly
             tnow = time.now()
@@ -382,7 +390,7 @@ class _XLogger:
                 xl.jemit_sync("attached", "periodic", isync)
 
             else:
-                t_rx, resp, resp_raw = req_(ctx, logspec.query, opts)
+                t_rx, resp, resp_raw = req_(ctx, logspec.query, logspec.opts)
                 srv_time = resp["time"]
                 srv_utc  = resp.get("utc")
                 xl.emit(resp_raw)

amari/xlog_test.py

@@ -300,11 +300,11 @@ def test_Reader_timestamp_from_sync_wo_utc():
 
 
 def test_LogSpec():
-    logspec = "stats[samples,rf]/60s"
+    logspec = 'stats[samples,rf,abc=123,def="hello world"]/60s'
     spec = xlog.LogSpec.parse(logspec)
 
     assert spec.query == "stats"
-    assert spec.optv == ["samples", "rf"]
+    assert spec.opts == {"samples": True, "rf": True, "abc": 123, "def": "hello world"}
     assert spec.period == 60.0
     assert str(spec) == logspec