built-in-metrics-aspnetcore.md

title	description	ms.topic	ms.date
ASP.NET Core Metrics	Review the metrics available for ASP.NET Core	reference	9/21/2023

ASP.NET Core Metrics

This article describes the metrics built-in for ASP.NET Core produced using the xref:System.Diagnostics.Metrics?displayProperty=nameWithType API. For a listing of metrics based on the older EventCounters API, see here.

• Meter: Microsoft.AspNetCore.Hosting
  • Instrument: http.server.request.duration
  • Instrument: http.server.active_requests
• Meter: Microsoft.AspNetCore.Routing
  • Instrument: aspnetcore.routing.match_attempts
• Meter: Microsoft.AspNetCore.Diagnostics
  • Instrument: aspnetcore.diagnostics.exceptions
• Meter: Microsoft.AspNetCore.RateLimiting
  • Instrument: aspnetcore.rate_limiting.active_request_leases
  • Instrument: aspnetcore.rate_limiting.request_lease.duration
  • Instrument: aspnetcore.rate_limiting.queued_requests
  • Instrument: aspnetcore.rate_limiting.request.time_in_queue
  • Instrument: aspnetcore.rate_limiting.requests
• Meter: Microsoft.AspNetCore.Server.Kestrel
  • Instrument: kestrel.active_connections
  • Instrument: kestrel.connection.duration
  • Instrument: kestrel.rejected_connections
  • Instrument: kestrel.queued_connections
  • Instrument: kestrel.queued_requests
  • Instrument: kestrel.upgraded_connections
  • Instrument: kestrel.tls_handshake.duration
  • Instrument: kestrel.active_tls_handshakes
• Meter: Microsoft.AspNetCore.Http.Connections
  • Instrument: signalr.server.connection.duration
  • Instrument: signalr.server.active_connections

Meter: Microsoft.AspNetCore.Hosting

Instrument: http.server.request.duration

Name	Instrument Type	Unit (UCUM)	Description
http.server.request.duration	Histogram	s	Measures the duration of inbound HTTP requests.

Attribute	Type	Description	Examples	Presence
http.route	string	The matched route.	{controller}/{action}/{id?}	If it's available.
error.type	string	Describes a class of error the operation ended with.	timeout; name_resolution_error; 500	If request has ended with an error.
http.request.method	string	HTTP request method.	GET; POST; HEAD	Always
http.response.status_code	int	HTTP response status code.	200	If one was sent.
network.protocol.name	string	OSI application layer or non-OSI equivalent.	amqp; http; mqtt	Always
network.protocol.version	string	Version of the protocol specified in network.protocol.name.	3.1.1	Always
url.scheme	string	The URI scheme component identifying the used protocol.	http; https	Always
aspnetcore.request.is_unhandled	boolean	True when the request was not handled by the application pipeline.	true	If the request was unhandled.

The time used to handle an inbound HTTP request as measured at the hosting layer of ASP.NET Core. The time measurement starts once the underlying web host has sufficiently parsed the HTTP request headers on the inbound network stream to identify the new request and initialize context data structures such as the xref:Microsoft.AspNetCore.Http.HttpContext. The time ends when the ASP.NET Core handler pipeline is finished executing, all response data has been sent, and context data structures for the request are being disposed.

Available staring in: ASP.NET Core 8.0

Instrument: http.server.active_requests

Name	Instrument Type	Unit (UCUM)	Description
http.server.active_requests	UpDownCounter	{request}	Measures the number of concurrent HTTP requests that are currently in-flight.

Attribute	Type	Description	Examples	Presence
http.request.method	string	HTTP request method. [1]	GET; POST; HEAD	Always
url.scheme	string	The URI scheme component identifying the used protocol.	http; https	Always

Available staring in: ASP.NET Core 8.0

Meter: Microsoft.AspNetCore.Routing

Instrument: aspnetcore.routing.match_attempts

Name	Instrument Type	Unit (UCUM)	Description
aspnetcore.routing.match_attempts	Counter	{match_attempt}	Number of requests that were attempted to be matched to an endpoint.

Attribute	Type	Description	Examples	Presence
aspnetcore.routing.match_status	string	Match result - success or failure	success; failure	Always
aspnetcore.routing.is_fallback_route	boolean	A value that indicates whether the matched route is a fallback route.	True	If a route was successfully matched.
http.route	string	The matched route	{controller}/{action}/{id?}	If a route was successfully matched.

Available staring in: ASP.NET Core 8.0

Meter: Microsoft.AspNetCore.Diagnostics

Instrument: aspnetcore.diagnostics.exceptions

Name	Instrument Type	Unit (UCUM)	Description
aspnetcore.diagnostics.exceptions	Counter	{exception}	Number of exceptions caught by exception handling middleware.

Attribute	Type	Description	Examples	Presence
aspnetcore.diagnostics.exception.result	string	ASP.NET Core exception middleware handling result	handled; unhandled	Always
aspnetcore.diagnostics.handler.type	string	Full type name of the IExceptionHandler implementation that handled the exception.	Contoso.MyHandler	If the exception was handled by this handler.
exception.type	string	The full name of exception type.	System.OperationCanceledException; Contoso.MyException	Always

aspnetcore.diagnostics.exception.result is one of the following:

Value	Description
handled	Exception was handled by the exception handling middleware.
unhandled	Exception was not handled by the exception handling middleware.
skipped	Exception handling was skipped because the response had started.
aborted	Exception handling didn't run because the request was aborted.

Available staring in: ASP.NET Core 8.0

Meter: Microsoft.AspNetCore.RateLimiting

Instrument: aspnetcore.rate_limiting.active_request_leases

Name	Instrument Type	Unit (UCUM)	Description
aspnetcore.rate_limiting.active_request_leases	UpDownCounter	{request}	Number of requests that are currently active on the server that hold a rate limiting lease.

Attribute	Type	Description	Examples	Presence
aspnetcore.rate_limiting.policy	string	Rate limiting policy name.	fixed; sliding; token	If the matched endpoint for the request had a rate-limiting policy.

Available staring in: ASP.NET Core 8.0

Instrument: aspnetcore.rate_limiting.request_lease.duration

Name	Instrument Type	Unit (UCUM)	Description
aspnetcore.rate_limiting.request_lease.duration	Histogram	s	The duration of the rate limiting lease held by requests on the server.

Attribute	Type	Description	Examples	Presence
aspnetcore.rate_limiting.policy	string	Rate limiting policy name.	fixed; sliding; token	If the matched endpoint for the request had a rate-limiting policy.

Available staring in: ASP.NET Core 8.0

Instrument: aspnetcore.rate_limiting.queued_requests

Name	Instrument Type	Unit (UCUM)	Description
aspnetcore.rate_limiting.queued_requests	UpDownCounter	{request}	Number of requests that are currently queued, waiting to acquire a rate limiting lease.

Attribute	Type	Description	Examples	Presence
aspnetcore.rate_limiting.policy	string	Rate limiting policy name.	fixed; sliding; token	If the matched endpoint for the request had a rate-limiting policy.

Available staring in: ASP.NET Core 8.0

Instrument: aspnetcore.rate_limiting.request.time_in_queue

Name	Instrument Type	Unit (UCUM)	Description
aspnetcore.rate_limiting.request.time_in_queue	Histogram	s	The time a request spent in a queue, waiting to acquire a rate limiting lease.

Attribute	Type	Description	Examples	Presence
aspnetcore.rate_limiting.policy	string	Rate limiting policy name.	fixed; sliding; token	If the matched endpoint for the request had a rate-limiting policy.
aspnetcore.rate_limiting.result	string	The rate limiting result shows whether lease was acquired or contains a rejection reason.	acquired; request_canceled	Always

aspnetcore.rate_limiting.result is one of the following:

Value	Description
acquired	Lease was acquired
endpoint_limiter	Lease request was rejected by the endpoint limiter
global_limiter	Lease request was rejected by the global limiter
request_canceled	Lease request was canceled

Available staring in: ASP.NET Core 8.0

Instrument: aspnetcore.rate_limiting.requests

Name	Instrument Type	Unit (UCUM)	Description
aspnetcore.rate_limiting.requests	Counter	{request}	Number of requests that tried to acquire a rate limiting lease.

Attribute	Type	Description	Examples	Presence
aspnetcore.rate_limiting.policy	string	Rate limiting policy name.	fixed; sliding; token	If the matched endpoint for the request had a rate-limiting policy.
aspnetcore.rate_limiting.result	string	The rate limiting result shows whether lease was acquired or contains a rejection reason.	acquired; request_canceled	Always

aspnetcore.rate_limiting.result is one of the following:

Value	Description
acquired	Lease was acquired
endpoint_limiter	Lease request was rejected by the endpoint limiter
global_limiter	Lease request was rejected by the global limiter
request_canceled	Lease request was canceled

Available staring in: ASP.NET Core 8.0

Meter: Microsoft.AspNetCore.Server.Kestrel

Instrument: kestrel.active_connections

Name	Instrument Type	Unit (UCUM)	Description
kestrel.active_connections	UpDownCounter	{connection}	Number of connections that are currently active on the server.

Attribute	Type	Description	Examples	Presence
network.transport	string	OSI transport layer or inter-process communication method.	tcp; unix	Always
network.type	string	OSI network layer or non-OSI equivalent.	ipv4; ipv6	If the transport is tcp or udp.
server.address	string	Server address - domain name if available without reverse DNS lookup, otherwise IP address or Unix domain socket name.	example.com	Always
server.port	int	Server port number	80; 8080; 443	If the transport is tcp or udp.

Available staring in: ASP.NET Core 8.0

Instrument: kestrel.connection.duration

Name	Instrument Type	Unit (UCUM)	Description
kestrel.connection.duration	Histogram	s	The duration of connections on the server.

Attribute	Type	Description	Examples	Presence
error.type	string	The full name of exception type.	System.OperationCanceledException; Contoso.MyException	If an exception was thrown.
network.protocol.name	string	OSI application layer or non-OSI equivalent.	http; web_sockets	Always
network.protocol.version	string	Version of the protocol specified in network.protocol.name.	1.1; 2	Always
network.transport	string	OSI transport layer or inter-process communication method.	tcp; unix	Always
network.type	string	OSI network layer or non-OSI equivalent.	ipv4; ipv6	If the transport is tcp or udp.
server.address	string	Server address - domain name if available without reverse DNS lookup, otherwise IP address or Unix domain socket name.	example.com	Always
server.port	int	Server port number	80; 8080; 443	If the transport is tcp or udp.
tls.protocol.version	string	TLS protocol version.	1.2; 1.3	If the connection is secured with TLS.

Available staring in: ASP.NET Core 8.0

Instrument: kestrel.rejected_connections

Name	Instrument Type	Unit (UCUM)	Description
kestrel.rejected_connections	Counter	{connection}	Number of connections rejected by the server.

Attribute	Type	Description	Examples	Presence
network.transport	string	OSI transport layer or inter-process communication method.	tcp; unix	Always
network.type	string	OSI network layer or non-OSI equivalent.	ipv4; ipv6	If the transport is tcp or udp.
server.address	string	Server address - domain name if available without reverse DNS lookup, otherwise IP address or Unix domain socket name.	example.com	Always
server.port	int	Server port number	80; 8080; 443	If the transport is tcp or udp.

Connections are rejected when the currently active count exceeds the value configured with MaxConcurrentConnections.

Available staring in: ASP.NET Core 8.0

Instrument: kestrel.queued_connections

Name	Instrument Type	Unit (UCUM)	Description
kestrel.queued_connections	UpDownCounter	{connection}	Number of connections that are currently queued and are waiting to start.

Attribute	Type	Description	Examples	Presence
network.transport	string	OSI transport layer or inter-process communication method.	tcp; unix	Always
network.transport	string	OSI network layer or non-OSI equivalent.	ipv4; ipv6	If the transport is tcp or udp.
server.address	string	Server address - domain name if available without reverse DNS lookup, otherwise IP address or Unix domain socket name.	example.com	Always
server.port	int	Server port number	80; 8080; 443	If the transport is tcp or udp.

Available staring in: ASP.NET Core 8.0

Instrument: kestrel.queued_requests

Name	Instrument Type	Unit (UCUM)	Description
kestrel.queued_requests	UpDownCounter	{request}	Number of HTTP requests on multiplexed connections (HTTP/2 and HTTP/3) that are currently queued and are waiting to start.

Attribute	Type	Description	Examples	Presence
network.protocol.name	string	OSI application layer or non-OSI equivalent.	http; web_sockets	Always
network.protocol.version	string	Version of the protocol specified in network.protocol.name.	1.1; 2	Always
network.transport	string	OSI transport layer or inter-process communication method.	tcp; unix	Always
network.transport	string	OSI network layer or non-OSI equivalent.	ipv4; ipv6	If the transport is tcp or udp.
server.address	string	Server address - domain name if available without reverse DNS lookup, otherwise IP address or Unix domain socket name.	example.com	Always
server.port	int	Server port number	80; 8080; 443	If the transport is tcp or udp.

Available staring in: ASP.NET Core 8.0

Instrument: kestrel.upgraded_connections

Name	Instrument Type	Unit (UCUM)	Description
kestrel.upgraded_connections	UpDownCounter	{connection}	Number of connections that are currently upgraded (WebSockets).

Attribute	Type	Description	Examples	Presence
network.transport	string	OSI transport layer or inter-process communication method.	tcp; unix	Always
network.transport	string	OSI network layer or non-OSI equivalent.	ipv4; ipv6	If the transport is tcp or udp.
server.address	string	Server address - domain name if available without reverse DNS lookup, otherwise IP address or Unix domain socket name.	example.com	Always
server.port	int	Server port number	80; 8080; 443	If the transport is tcp or udp.

The counter only tracks HTTP/1.1 connections.

Available staring in: ASP.NET Core 8.0

Instrument: kestrel.tls_handshake.duration

Name	Instrument Type	Unit (UCUM)	Description
kestrel.tls_handshake.duration	Histogram	s	The duration of TLS handshakes on the server.

Attribute	Type	Description	Examples	Presence
error.type	string	The full name of exception type.	System.OperationCanceledException; Contoso.MyException	If an exception was thrown.
network.transport	string	OSI transport layer or inter-process communication method.	tcp; unix	Always
network.transport	string	OSI network layer or non-OSI equivalent.	ipv4; ipv6	If the transport is tcp or udp.
server.address	string	Server address - domain name if available without reverse DNS lookup, otherwise IP address or Unix domain socket name.	example.com	Always
server.port	int	Server port number	80; 8080; 443	If the transport is tcp or udp.
tls.protocol.version	string	TLS protocol version.	1.2; 1.3	If the connection is secured with TLS.

Available staring in: ASP.NET Core 8.0

Instrument: kestrel.active_tls_handshakes

Name	Instrument Type	Unit (UCUM)	Description
kestrel.active_tls_handshakes	UpDownCounter	{handshake}	Number of TLS handshakes that are currently in progress on the server.

Attribute	Type	Description	Examples	Presence
network.transport	string	OSI transport layer or inter-process communication method.	tcp; unix	Always
network.transport	string	OSI network layer or non-OSI equivalent.	ipv4; ipv6	If the transport is tcp or udp.
server.address	string	Server address - domain name if available without reverse DNS lookup, otherwise IP address or Unix domain socket name.	example.com	Always
server.port	int	Server port number	80; 8080; 443	If the transport is tcp or udp.

Available staring in: ASP.NET Core 8.0

Meter: Microsoft.AspNetCore.Http.Connections

Instrument: signalr.server.connection.duration

Name	Instrument Type	Unit (UCUM)	Description
signalr.server.connection.duration	Histogram	s	The duration of connections on the server.

Attribute	Type	Description	Examples	Presence
signalr.connection.status	string	SignalR HTTP connection closure status.	app_shutdown; timeout	Always
signalr.transport	string	SignalR transport type	web_sockets; long_polling	Always

signalr.connection.status is one of the following:

Value	Description
normal_closure	The connection was closed normally.
timeout	The connection was closed due to a timeout.
app_shutdown	The connection was closed because the app is shutting down.

signalr.transport is one of the following:

Value	Description
server_sent_events	ServerSentEvents protocol
long_polling	LongPolling protocol
web_sockets	WebSockets protocol

Available staring in: ASP.NET Core 8.0

Instrument: signalr.server.active_connections

Name	Instrument Type	Unit (UCUM)	Description
signalr.server.active_connections	UpDownCounter	{connection}	Number of connections that are currently active on the server.

Attribute	Type	Description	Examples	Presence
signalr.connection.status	string	SignalR HTTP connection closure status.	app_shutdown; timeout	Always
signalr.transport	string	SignalR transport type	web_sockets; long_polling	Always

signalr.connection.status is one of the following:

Value	Description
normal_closure	The connection was closed normally.
timeout	The connection was closed due to a timeout.
app_shutdown	The connection was closed because the app is shutting down.

signalr.transport is one of the following:

Value	Description
server_sent_events	ServerSentEvents protocol
long_polling	LongPolling protocol
web_sockets	WebSockets protocol

Available staring in: ASP.NET Core 8.0