feat(telemetry): add telemetry support for user agent parsing by BenjaminAbt · Pull Request #90 · mycsharp/HttpUserAgentParser

BenjaminAbt · 2025-12-27T15:16:59Z

fixes Add telemetry (aka event-counters) #6
due to breaking change with fluent api, bump version

gfoidl

Instead of the event source, I'd prefer to use OTel metrics via the meters.
Especially as we don't write to the event stream (which could be read e.g. via PerfView), and I don't think we need the diagnostic events.

gfoidl · 2025-12-27T15:48:14Z

src/HttpUserAgentParser.AspNetCore/Telemetry/HttpUserAgentParserAspNetCoreEventSource.cs

+    internal void UserAgentPresent()
+    {
+        if (!IsEnabled()) return;
+        _userAgentPresent?.Increment();


As we don't write an event, should we use metrics (via meter factory) instead?
I'd prefer the OTel metrics here.

There are too many projects that do not use OTEL - even I/we currently still use native app insights in almost all projects because OTEL features are missing.

Hm, with UseAzureMonitor I see metrics in Azure. What features are there missing?

But we would still enforce everybody to use OTEL as foundation... I am not happy with that.

gfoidl

Then OK.

BenjaminAbt · 2025-12-27T19:38:07Z

@gfoidl , I added a telemetry hub and exposed otel native meters and dotnet metrics.
I think I dont have added any overhead.

gfoidl

For the OTel attributes we should follow the semantic convention (now, because changing it later would be a breaking change).

Sorry for the delay.

src/HttpUserAgentParser.AspNetCore/Telemetry/HttpUserAgentParserAspNetCoreMeters.cs

BenjaminAbt · 2026-01-12T12:23:03Z

@gfoidl no problem. I expected the delay, since it was the holidays. Happy New Year.

BenjaminAbt · 2026-01-31T19:52:14Z

@gfoidl there is this note

When instruments are measuring durations, seconds (i.e. s) SHOULD be used.

does this really make sense? We have parse.duration which is always 0s because its way faster than 0s

gfoidl · 2026-02-02T16:04:12Z

does this really make sense? We have parse.duration which is always 0s because its way faster than 0s

Makes sense, but the value has to be given as floating point number. Then the tools to display should show it as ms or that like.

gfoidl · 2026-02-05T13:23:23Z

src/HttpUserAgentParser.AspNetCore/readme.md

+- `useragent-present` (counter)
+- `useragent-missing` (counter)


Suggested change

- `useragent-present` (counter)

- `useragent-missing` (counter)

- `user_agent.present` (counter)

- `user_agent.missing` (counter)

gfoidl · 2026-02-05T13:27:18Z

src/HttpUserAgentParser.MemoryCache/Telemetry/HttpUserAgentParserMemoryCacheMeters.cs

+        s_meter = meter ?? new Meter(MeterName);
+
+        s_cacheHit = s_meter.CreateCounter<long>(
+            name: "cache.hit",


Suggested change

name: "cache.hit",

name: "user_agent_parser.cache.hit",

?
Otherwise it's only "cache" and which one is meant in a typical app with several caches.

gfoidl · 2026-02-05T13:27:26Z

src/HttpUserAgentParser.MemoryCache/Telemetry/HttpUserAgentParserMemoryCacheMeters.cs

+            description: "MemoryCache cache hit");
+
+        s_cacheMiss = s_meter.CreateCounter<long>(
+            name: "cache.miss",


Suggested change

name: "cache.miss",

name: "user_agent_parser.cache.miss",

gfoidl · 2026-02-05T13:27:36Z

src/HttpUserAgentParser.MemoryCache/Telemetry/HttpUserAgentParserMemoryCacheMeters.cs

+            description: "MemoryCache cache miss");
+
+        s_cacheSize = s_meter.CreateObservableGauge<long>(
+            name: "cache.size",


Suggested change

name: "cache.size",

name: "user_agent_parser.cache.size",

gfoidl · 2026-02-05T13:29:05Z

src/HttpUserAgentParser.MemoryCache/readme.md

+- `cache-hit` (counter)
+- `cache-miss` (counter)
+- `cache-size` (observable gauge)


Suggested change

- `cache-hit` (counter)

- `cache-miss` (counter)

- `cache-size` (observable gauge)

- `user_agent_parser.cache.hit` (counter)

- `user_agent_parser.cache.miss` (counter)

- `user_agent_parser.cache.size` (observable gauge)

gfoidl · 2026-02-05T13:36:52Z

src/HttpUserAgentParser/Telemetry/HttpUserAgentParserEventSource.cs

+    /// counter reports a correct value once a listener attaches.
+    /// </remarks>
+    [NonEvent]
+    internal static void ConcurrentCacheSizeSet(int size) => HttpUserAgentParserTelemetryState.SetConcurrentCacheSize(size);


Suggested change

internal static void ConcurrentCacheSizeSet(int size) => HttpUserAgentParserTelemetryState.SetConcurrentCacheSize(size);

internal static void CacheSizeSet(int size) => HttpUserAgentParserTelemetryState.SetConcurrentCacheSize(size);

gfoidl · 2026-02-05T13:38:54Z

src/HttpUserAgentParser/readme.md

+	.AddHttpUserAgentParser();
+```
+
+### ConcurrentDictionary cache


Suggested change

### ConcurrentDictionary cache

### Cached parser

?
The CDN and even concurrent shouldn't be exposed, as they're details.

gfoidl · 2026-02-05T13:39:12Z

src/HttpUserAgentParser/readme.md

+- `cache-concurrentdictionary-hit` (incrementing)
+- `cache-concurrentdictionary-miss` (incrementing)
+- `cache-concurrentdictionary-size` (polling)


Suggested change

- `cache-concurrentdictionary-hit` (incrementing)

- `cache-concurrentdictionary-miss` (incrementing)

- `cache-concurrentdictionary-size` (polling)

- `cache-hit` (incrementing)

- `cache-miss` (incrementing)

- `cache-size` (polling)

gfoidl · 2026-02-05T13:39:37Z

src/HttpUserAgentParser/readme.md

+- `parse-requests` (counter)
+- `parse-duration` (histogram, ms)
+- `cache-concurrentdictionary-hit` (counter)
+- `cache-concurrentdictionary-miss` (counter)
+- `cache-concurrentdictionary-size` (observable gauge)


Please update to current used names.

gfoidl · 2026-02-05T13:40:59Z

README.md

+
+Core (`MyCSharp.HttpUserAgentParser`)
+
+- `parse-requests`


Need to be updated.

BenjaminAbt added 2 commits December 27, 2025 15:58

feat(telemetry): add telemetry support for user agent parsing

3d1abc6

feat(telemetry): add telemetry support and documentation

26636f1

BenjaminAbt requested a review from gfoidl December 27, 2025 15:17

gfoidl reviewed Dec 27, 2025

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gfoidl approved these changes Dec 27, 2025

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BenjaminAbt added 3 commits December 27, 2025 20:17

feat(telemetry): add native metrics support for user agent parser

770ece1

feat(telemetry): enhance metrics and telemetry documentation

081727e

feat(telemetry): enhance telemetry documentation and add meters support

055ed40

BenjaminAbt requested a review from gfoidl December 27, 2025 19:37

BenjaminAbt added 2 commits December 27, 2025 20:43

refactor(telemetry): simplify method signatures and improve readability

3ac5975

refactor(telemetry): remove DEBUG conditional compilation

44f030f

gfoidl requested changes Jan 12, 2026

View reviewed changes

src/HttpUserAgentParser.AspNetCore/Telemetry/HttpUserAgentParserAspNetCoreMeters.cs Outdated Show resolved Hide resolved

src/HttpUserAgentParser.AspNetCore/Telemetry/HttpUserAgentParserAspNetCoreMeters.cs Outdated Show resolved Hide resolved

BenjaminAbt added 2 commits January 31, 2026 20:53

refactor(telemetry): update metric naming conventions

1e97351

docs(copilot): add comprehensive instructions for Copilot usage

067b733

refactor(telemetry): update duration metrics to seconds

0478999

BenjaminAbt requested a review from gfoidl February 5, 2026 11:58

gfoidl requested changes Feb 5, 2026

View reviewed changes

		- `useragent-present` (counter)
		- `useragent-missing` (counter)

	internal static void ConcurrentCacheSizeSet(int size) => HttpUserAgentParserTelemetryState.SetConcurrentCacheSize(size);
	internal static void CacheSizeSet(int size) => HttpUserAgentParserTelemetryState.SetConcurrentCacheSize(size);

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BenjaminAbt commented Jan 12, 2026

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BenjaminAbt commented Dec 27, 2025 •

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BenjaminAbt commented Dec 27, 2025 •

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