Allow Prometheus parser to handle missing space

If there is no delimiter separating the labels and value when parsing
the Prometheus format the parser currently will chop off the first digit
of the value. Instead, allow a missing delimiter in the Prometheus
format to align with what the Go parser does.

In addition, add a test to specifically check that a delimiter is still
required in OpenMetrics.

Signed-off-by: Chris Marchbanks <csmarchbanks@gmail.com>

prometheus_client/parser.py

@@ -116,8 +116,8 @@ def _parse_sample(text):
         name = text[:label_start].strip()
         # We ignore the starting curly brace
         label = text[label_start + 1:label_end]
-        # The value is after the label end (ignoring curly brace and space)
-        value, timestamp = _parse_value_and_timestamp(text[label_end + 2:])
+        # The value is after the label end (ignoring curly brace)
+        value, timestamp = _parse_value_and_timestamp(text[label_end + 1:])
         return Sample(name, _parse_labels(label), value, timestamp)
 
     # We don't have labels

tests/openmetrics/test_parser.py

@@ -642,6 +642,8 @@ def test_invalid_input(self):
             ('a{a""} 1\n# EOF\n'),
             ('a{a=} 1\n# EOF\n'),
             ('a{a="} 1\n# EOF\n'),
+            # Missing delimiters.
+            ('a{a="1"}1\n# EOF\n'),
             # Missing or extra commas.
             ('a{a="1"b="2"} 1\n# EOF\n'),
             ('a{a="1",,b="2"} 1\n# EOF\n'),

tests/test_parser.py

@@ -146,13 +146,15 @@ def test_spaces(self):
 a   {    foo   =  "buz"   }    3
 a\t {  \t foo\t = "biz"\t  } \t 4
 a \t{\t foo   = "boz"\t}\t 5
+a{foo="bez"}6
 """)
         metric_family = CounterMetricFamily("a", "help", labels=["foo"])
         metric_family.add_metric(["bar"], 1)
         metric_family.add_metric(["baz"], 2)
         metric_family.add_metric(["buz"], 3)
         metric_family.add_metric(["biz"], 4)
         metric_family.add_metric(["boz"], 5)
+        metric_family.add_metric(["bez"], 6)
         self.assertEqualMetrics([metric_family], list(families))
 
     def test_commas(self):