influxdb: simplify and document pattern matching. Closes #166

RELEASE_NOTES.rst

@@ -3,6 +3,20 @@
 Release notes
 =============
 
+unreleased [2.x]
+----------------
+
+* The format of the influxdb pattern file is simplified. The procedure to
+  edit patterns is also changed to modifying the pattern file and calling:
+  ``artiq_rpctool.py ::1 3248 call scan_patterns`` (or restarting the bridge)
+  The patterns can be converted to the new format using this code snippet::
+
+    from artiq.protocols import pyon
+    patterns = pyon.load_file("influxdb_patterns.pyon")
+    for p in patterns:
+        print(p)
+
+
 unreleased
 ----------
 

artiq/frontend/artiq_influxdb.py

@@ -21,7 +21,15 @@ logger = logging.getLogger(__name__)
 
 def get_argparser():
     parser = argparse.ArgumentParser(
-        description="ARTIQ data to InfluxDB bridge")
+        description="ARTIQ data to InfluxDB bridge",
+        epilog="Pattern matching works as follows. "
+               "The default action on a key (dataset name) is to log it. "
+               "Then the patterns are traversed in order and glob-matched "
+               "with the key. "
+               "Optional + and - pattern prefixes specify whether to ignore or "
+               "log keys matching the rest of the pattern. "
+               "Default (in the absence of prefix) is to ignore. Last matched "
+               "pattern takes precedence.")
     group = parser.add_argument_group("master")
     group.add_argument(
         "--server-master", default="::1",
@@ -46,8 +54,10 @@ def get_argparser():
         "--table", default="lab", help="table name to use")
     group = parser.add_argument_group("filter")
     group.add_argument(
-        "--pattern-file", default="influxdb_patterns.pyon",
-        help="file to save the patterns in (default: %(default)s)")
+        "--pattern-file", default="influxdb_patterns.cfg",
+        help="file to load the patterns from (default: %(default)s). "
+             "If the file is not found, no patterns are loaded "
+             "(everything is logged).")
     simple_network_args(parser, [("control", "control", 3248)])
     verbosity_args(parser)
     return parser
@@ -177,14 +187,20 @@ class MasterReader(TaskObject):
 class Filter:
     def __init__(self, pattern_file):
         self.pattern_file = pattern_file
-        self.patterns = []
+        self.scan_patterns()
+
+    def scan_patterns(self):
+        """(Re)load the patterns file."""
         try:
-            self.patterns = pyon.load_file(self.pattern_file)
+            with open(self.pattern_file, "r") as f:
+                self.patterns = []
+                for line in f:
+                    line = line.rstrip()
+                    if line:
+                        self.patterns.append(line)
         except FileNotFoundError:
             logger.info("no pattern file found, logging everything")
-
-    def _save(self):
-        pyon.store_file(self.pattern_file, self.patterns)
+            self.patterns = []
 
     # Privatize so that it is not shown in artiq_rpctool list-methods.
     def _filter(self, k):
@@ -197,32 +213,6 @@ class Filter:
                 take = sign
         return take == "+"
 
-    def add_pattern(self, pattern, index=None):
-        """Add a pattern.
-
-        Optional + and - pattern prefixes specify whether to ignore or log
-        keys matching the rest of the pattern.
-        Default (in the absence of prefix) is to ignore. Keys that match no
-        pattern are logged. Last matched pattern takes precedence.
-
-        The optional index parameter specifies where to insert the pattern.
-        By default, patterns are added at the end. If index is an integer, it
-        specifies the index where the pattern is inserted. If it is a string,
-        that string must match an existing pattern and the new pattern is
-        inserted immediately after it."""
-        if pattern not in self.patterns:
-            if index is None:
-                index = len(self.patterns)
-            if isinstance(index, str):
-                index = self.patterns.index(index) + 1
-            self.patterns.insert(index, pattern)
-        self._save()
-
-    def remove_pattern(self, pattern):
-        """Remove a pattern."""
-        self.patterns.remove(pattern)
-        self._save()
-
     def get_patterns(self):
         """Show existing patterns."""
         return self.patterns