remove pickle-based stats output altogether

* update munin plugin to read JSON, not pickle
* update docs

docs/stats.rst

@@ -309,15 +309,14 @@ and the next time the gatherer is started, it will start listening on the
 given port. The portnum file is actually a "strports specification string",
 as described in :doc:`configuration`.
 
-Once running, the stats gatherer will create a standard python "pickle" file
-in ``$BASEDIR/stats.pickle``, and a standard JSON file in
+Once running, the stats gatherer will create a standard JSON file in
 ``$BASEDIR/stats.json``. Once a minute, the gatherer will pull stats
-information from every connected node and write them into the pickle. The
-pickle will contain a dictionary, in which node identifiers (known as "tubid"
-strings) are the keys, and the values are a dict with 'timestamp', 'nickname',
-and 'stats' keys. d[tubid][stats] will contain the stats dictionary as made
-available at http://localhost:3456/statistics?t=json . The pickle file will
-only contain the most recent update from each node.
+information from every connected node and write them into the file. The file
+will contain a dictionary, in which node identifiers (known as "tubid"
+strings) are the keys, and the values are a dict with 'timestamp',
+'nickname', and 'stats' keys. d[tubid][stats] will contain the stats
+dictionary as made available at http://localhost:3456/statistics?t=json . The
+file will only contain the most recent update from each node.
 
 Other tools can be built to examine these stats and render them into
 something useful. For example, a tool could sum the
@@ -336,7 +335,7 @@ last year).
 
 Most of the plugins are designed to pull stats from a single Tahoe node, and
 are configured with the e.g. http://localhost:3456/statistics?t=json URL. The
-"tahoe_stats" plugin is designed to read from the pickle file created by the
+"tahoe_stats" plugin is designed to read from the JSON file created by the
 stats-gatherer. Some plugins are to be used with the disk watcher, and a few
 (like tahoe_nodememory) are designed to watch the node processes directly
 (and must therefore run on the same host as the target node).

misc/operations_helpers/munin/tahoe-stats.plugin-conf

@@ -1,12 +1,12 @@
 [tahoe_storage_allocated]
-env.statsfile /home/robk/trees/tahoe/stats_gatherer/stats.pickle
+env.statsfile /home/robk/trees/tahoe/stats_gatherer/stats.json
 [tahoe_storage_consumed]
-env.statsfile /home/robk/trees/tahoe/stats_gatherer/stats.pickle
+env.statsfile /home/robk/trees/tahoe/stats_gatherer/stats.json
 [tahoe_runtime_load_avg]
-env.statsfile /home/robk/trees/tahoe/stats_gatherer/stats.pickle
+env.statsfile /home/robk/trees/tahoe/stats_gatherer/stats.json
 [tahoe_runtime_load_peak]
-env.statsfile /home/robk/trees/tahoe/stats_gatherer/stats.pickle
+env.statsfile /home/robk/trees/tahoe/stats_gatherer/stats.json
 [tahoe_storage_bytes_added]
-env.statsfile /home/robk/trees/tahoe/stats_gatherer/stats.pickle
+env.statsfile /home/robk/trees/tahoe/stats_gatherer/stats.json
 [tahoe_storage_bytes_freed]
-env.statsfile /home/robk/trees/tahoe/stats_gatherer/stats.pickle
+env.statsfile /home/robk/trees/tahoe/stats_gatherer/stats.json

misc/operations_helpers/munin/tahoe_stats

@@ -1,7 +1,7 @@
 #!/usr/bin/env python
 
 import os
-import pickle
+import json
 import re
 import sys
 import time
@@ -428,7 +428,7 @@ def smash_name(name):
 
 def open_stats(fname):
     f = open(fname, 'rb')
-    stats = pickle.load(f)
+    stats = json.load(f)
     f.close()
     return stats
 

src/allmydata/stats.py

@@ -1,7 +1,6 @@
 
 import json
 import os
-import pickle
 import pprint
 import time
 from collections import deque
@@ -241,23 +240,23 @@ def got_stats(self, stats, tubid, nickname):
         print '"%s" [%s]:' % (nickname, tubid)
         pprint.pprint(stats)
 
-class PickleStatsGatherer(StdOutStatsGatherer):
+class JSONStatsGatherer(StdOutStatsGatherer):
     # inherit from StdOutStatsGatherer for connect/disconnect notifications
 
     def __init__(self, basedir=u".", verbose=True):
         self.verbose = verbose
         StatsGatherer.__init__(self, basedir)
-        self.picklefile = os.path.join(basedir, "stats.pickle")
         self.jsonfile = os.path.join(basedir, "stats.json")
 
-        if os.path.exists(self.picklefile):
-            f = open(self.picklefile, 'rb')
+        if os.path.exists(self.jsonfile):
+            f = open(self.jsonfile, 'rb')
             try:
-                self.gathered_stats = pickle.load(f)
+                self.gathered_stats = json.load(f)
             except Exception:
-                print ("Error while attempting to load pickle file %s.\n"
-                       "You may need to restore this file from a backup, or delete it if no backup is available.\n" %
-                       quote_local_unicode_path(self.picklefile))
+                print ("Error while attempting to load stats file %s.\n"
+                       "You may need to restore this file from a backup,"
+                       " or delete it if no backup is available.\n" %
+                       quote_local_unicode_path(self.jsonfile))
                 raise
             f.close()
         else:
@@ -268,20 +267,9 @@ def got_stats(self, stats, tubid, nickname):
         s['timestamp'] = time.time()
         s['nickname'] = nickname
         s['stats'] = stats
-        self.dump_pickle()
         self.dump_json()
 
-    def dump_pickle(self):
-        tmp = "%s.tmp" % (self.picklefile,)
-        f = open(tmp, 'wb')
-        pickle.dump(self.gathered_stats, f)
-        f.close()
-        if os.path.exists(self.picklefile):
-            os.unlink(self.picklefile)
-        os.rename(tmp, self.picklefile)
-
     def dump_json(self):
-        # Same logic as pickle, but using JSON instead.
         tmp = "%s.tmp" % (self.jsonfile,)
         f = open(tmp, 'wb')
         json.dump(self.gathered_stats, f)
@@ -303,7 +291,7 @@ def __init__(self, basedir=".", verbose=False):
         self.tub.setOption("logRemoteFailures", True)
         self.tub.setOption("expose-remote-exception-types", False)
 
-        self.stats_gatherer = PickleStatsGatherer(self.basedir, verbose)
+        self.stats_gatherer = JSONStatsGatherer(self.basedir, verbose)
         self.stats_gatherer.setServiceParent(self)
 
         portnumfile = os.path.join(self.basedir, "portnum")

topfiles/PR242.docs

@@ -0,0 +1,4 @@
+The "stats gatherer" (created with 'tahoe create-stats-gatherer') now updates
+a JSON file named "stats.json"; previously it used Pickle and "stats.pickle".
+The munin plugins in misc/operations_helpers/munin/ have been updated to
+match, and must be re-installed and re-configured if you use munin.