From 32015e1109bc955697353d8f8088e3f6b538d12c Mon Sep 17 00:00:00 2001 From: Erik Johnston Date: Wed, 2 May 2018 16:52:42 +0100 Subject: [PATCH] Escape label values in prometheus metrics --- synapse/metrics/metric.py | 22 ++++++++++++++++++++-- tests/metrics/test_metric.py | 21 ++++++++++++++++++++- 2 files changed, 40 insertions(+), 3 deletions(-) diff --git a/synapse/metrics/metric.py b/synapse/metrics/metric.py index 89bd47c3f7..1a09e417c9 100644 --- a/synapse/metrics/metric.py +++ b/synapse/metrics/metric.py @@ -16,6 +16,7 @@ from itertools import chain import logging +import re logger = logging.getLogger(__name__) @@ -56,8 +57,7 @@ class BaseMetric(object): return not len(self.labels) def _render_labelvalue(self, value): - # TODO: escape backslashes, quotes and newlines - return '"%s"' % (value) + return '"%s"' % (_escape_label_value(value),) def _render_key(self, values): if self.is_scalar(): @@ -299,3 +299,21 @@ class MemoryUsageMetric(object): "process_psutil_rss:total %d" % sum_rss, "process_psutil_rss:count %d" % len_rss, ] + + +def _escape_character(c): + """Replaces a single character with its escape sequence. + """ + if c == "\\": + return "\\\\" + elif c == "\"": + return "\\\"" + elif c == "\n": + return "\\n" + return c + + +def _escape_label_value(value): + """Takes a label value and escapes quotes, newlines and backslashes + """ + return re.sub(r"([\n\"\\])", lambda m: _escape_character(m.group(1)), value) diff --git a/tests/metrics/test_metric.py b/tests/metrics/test_metric.py index 39bde6e3f8..069c0be762 100644 --- a/tests/metrics/test_metric.py +++ b/tests/metrics/test_metric.py @@ -16,7 +16,8 @@ from tests import unittest from synapse.metrics.metric import ( - CounterMetric, CallbackMetric, DistributionMetric, CacheMetric + CounterMetric, CallbackMetric, DistributionMetric, CacheMetric, + _escape_label_value, ) @@ -171,3 +172,21 @@ class CacheMetricTestCase(unittest.TestCase): 'cache:size{name="cache_name"} 1', 'cache:evicted_size{name="cache_name"} 2', ]) + + +class LabelValueEscapeTestCase(unittest.TestCase): + def test_simple(self): + string = "safjhsdlifhyskljfksdfh" + self.assertEqual(string, _escape_label_value(string)) + + def test_escape(self): + self.assertEqual( + "abc\\\"def\\nghi\\\\", + _escape_label_value("abc\"def\nghi\\"), + ) + + def test_sequence_of_escapes(self): + self.assertEqual( + "abc\\\"def\\nghi\\\\\\n", + _escape_label_value("abc\"def\nghi\\\n"), + )