From 8bbe87f42d7736b3f11db0fcfb4557b214e0356d Mon Sep 17 00:00:00 2001
From: Christian Svensson <blue@cmd.nu>
Date: Tue, 23 Jun 2020 19:06:01 +0200
Subject: [PATCH] Set Content-Length for Metrics requests (#7730)
HTTP requires the response to contain a Content-Length header unless chunked encoding is being used.
Prometheus metrics endpoint did not set this, causing software such as prometheus-proxy to not be able to scrape synapse for metrics.
Signed-off-by: Christian Svensson <blue@cmd.nu>
---
changelog.d/7730.bugfix | 1 +
synapse/metrics/_exposition.py | 5 ++++-
2 files changed, 5 insertions(+), 1 deletion(-)
create mode 100644 changelog.d/7730.bugfix
diff --git a/changelog.d/7730.bugfix b/changelog.d/7730.bugfix
new file mode 100644
index 0000000000..9da254b56c
--- /dev/null
+++ b/changelog.d/7730.bugfix
@@ -0,0 +1 @@
+Fix missing `Content-Length` on HTTP responses from the metrics handler.
diff --git a/synapse/metrics/_exposition.py b/synapse/metrics/_exposition.py
index ab7f948ed4..4304c60d56 100644
--- a/synapse/metrics/_exposition.py
+++ b/synapse/metrics/_exposition.py
@@ -208,6 +208,7 @@ class MetricsHandler(BaseHTTPRequestHandler):
raise
self.send_response(200)
self.send_header("Content-Type", CONTENT_TYPE_LATEST)
+ self.send_header("Content-Length", str(len(output)))
self.end_headers()
self.wfile.write(output)
@@ -261,4 +262,6 @@ class MetricsResource(Resource):
def render_GET(self, request):
request.setHeader(b"Content-Type", CONTENT_TYPE_LATEST.encode("ascii"))
- return generate_latest(self.registry)
+ response = generate_latest(self.registry)
+ request.setHeader(b"Content-Length", str(len(response)))
+ return response
--
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