Guard against empty- or double- sending.

2 files changed, 25 insertions, 0 deletions

diff --git a/statsd/client.py b/statsd/client.py
index 0770247..77207a4 100644
--- a/statsd/client.py
+++ b/statsd/client.py
@@ -16,6 +16,8 @@ class Timer(object):
         self.stat = stat
         self.rate = rate
         self.ms = None
+        self._sent = False
+        self._start_time = None
 
     def __call__(self, f):
         @wraps(f)
@@ -35,6 +37,8 @@ class Timer(object):
         return self
 
     def stop(self, send=True):
+        if self._start_time is None:
+            raise RuntimeError('Timer has not started.')
         dt = time.time() - self._start_time
         self.ms = int(round(1000 * dt))  # Convert to milliseconds.
         if send:
@@ -42,6 +46,11 @@ class Timer(object):
         return self
 
     def send(self):
+        if self.ms is None:
+            raise RuntimeError('No data recorded.')
+        if self._sent:
+            raise RuntimeError('Already sent data.')
+        self._sent = True
         self.client.timing(self.stat, self.ms, self.rate)
 
 
diff --git a/statsd/tests.py b/statsd/tests.py
index 2ffd6b3..4080a9c 100644
--- a/statsd/tests.py
+++ b/statsd/tests.py
@@ -317,6 +317,22 @@ def test_timer_object_rate():
     _timer_check(sc, 1, 'foo', 'ms@0.5')
 
 
+def test_timer_object_no_send_twice():
+    sc = _client()
+
+    t = sc.timer('foo').start()
+    t.stop()
+
+    with assert_raises(RuntimeError):
+        t.send()
+
+
+def test_timer_object_stop_without_start():
+    sc = _client()
+    with assert_raises(RuntimeError):
+        sc.timer('foo').stop()
+
+
 def test_pipeline():
     sc = _client()
     pipe = sc.pipeline()