Semantic Conventions for HTTP Metrics

NOTICE Semantic Conventions are moving to a new location.

No changes to this document are allowed.

The conventions described in this section are HTTP specific. When HTTP operations occur, metric events about those operations will be generated and reported to provide insight into the operations. By adding HTTP attributes to metric events it allows for finely tuned filtering.

Disclaimer: These are initial HTTP metric instruments and attributes but more may be added in the future.

Warning Existing HTTP instrumentations that are using v1.20.0 of this document (or prior):
SHOULD NOT change the version of the HTTP or networking attributes that they emit until the HTTP semantic conventions are marked stable (HTTP stabilization will include stabilization of a core set of networking attributes which are also used in HTTP instrumentations).
SHOULD introduce an environment variable OTEL_SEMCONV_STABILITY_OPT_IN in the existing major version which supports the following values:
none - continue emitting whatever version of the old experimental HTTP and networking attributes the instrumentation was emitting previously. This is the default value.
http - emit the new, stable HTTP and networking attributes, and stop emitting the old experimental HTTP and networking attributes that the instrumentation emitted previously.
http/dup - emit both the old and the stable HTTP and networking attributes, allowing for a seamless transition.
SHOULD maintain (security patching at a minimum) the existing major version for at least six months after it starts emitting both sets of attributes.
SHOULD drop the environment variable in the next major version (stable next major version SHOULD NOT be released prior to October 1, 2023).

HTTP Server

Metric: `http.server.duration`

This metric is required.

This metric SHOULD be specified with ExplicitBucketBoundaries of [ 0, 0.005, 0.01, 0.025, 0.05, 0.075, 0.1, 0.25, 0.5, 0.75, 1, 2.5, 5, 7.5, 10 ].

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

Attribute	Type	Description	Examples	Requirement Level
`http.route`	string	The matched route (path template in the format used by the respective server framework). See note below [1]	`/users/:userID?`; `{controller}/{action}/{id?}`	Conditionally Required: If and only if it’s available
`http.request.method`	string	HTTP request method.	`GET`; `POST`; `HEAD`	Required
`http.response.status_code`	int	HTTP response status code.	`200`	Conditionally Required: If and only if one was received/sent.
`network.protocol.name`	string	OSI Application Layer or non-OSI equivalent. The value SHOULD be normalized to lowercase.	`amqp`; `http`; `mqtt`	Recommended
`network.protocol.version`	string	Version of the application layer protocol used. See note below. [2]	`3.1.1`	Recommended
`server.address`	string	Name of the local HTTP server that received the request. [3]	`example.com`	Required
`server.port`	int	Port of the local HTTP server that received the request. [4]	`80`; `8080`; `443`	Conditionally Required: [5]
`url.scheme`	string	The URI scheme component identifying the used protocol.	`http`; `https`	Required

[1]: MUST NOT be populated when this is not supported by the HTTP server framework as the route attribute should have low-cardinality and the URI path can NOT substitute it. SHOULD include the application roottrace/semantic_conventions/http.md#http-server-definitions) if there is one.

[2]: network.protocol.version refers to the version of the protocol used and might be different from the protocol client’s version. If the HTTP client used has a version of 0.27.2, but sends HTTP version 1.1, this attribute should be set to 1.1.

[3]: Determined by using the first of the following that applies

The primary server nametrace/semantic_conventions/http.md#http-server-definitions) of the matched virtual host. MUST only include host identifier.
Host identifier of the request target if it’s sent in absolute-form.
Host identifier of the Host header

SHOULD NOT be set if only IP address is available and capturing name would require a reverse DNS lookup.

[4]: Determined by using the first of the following that applies

Port identifier of the primary server hosttrace/semantic_conventions/http.md#http-server-definitions) of the matched virtual host.
Port identifier of the request target if it’s sent in absolute-form.
Port identifier of the Host header

[5]: If not default (80 for http scheme, 443 for https).

Metric: `http.server.active_requests`

This metric is optional.

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	Requirement Level
`http.request.method`	string	HTTP request method.	`GET`; `POST`; `HEAD`	Required
`server.address`	string	Name of the local HTTP server that received the request. [1]	`example.com`	Required
`server.port`	int	Port of the local HTTP server that received the request. [2]	`80`; `8080`; `443`	Conditionally Required: [3]
`url.scheme`	string	The URI scheme component identifying the used protocol.	`http`; `https`	Required

[1]: Determined by using the first of the following that applies

The primary server nametrace/semantic_conventions/http.md#http-server-definitions) of the matched virtual host. MUST only include host identifier.
Host identifier of the request target if it’s sent in absolute-form.
Host identifier of the Host header

SHOULD NOT be set if only IP address is available and capturing name would require a reverse DNS lookup.

[2]: Determined by using the first of the following that applies

Port identifier of the primary server hosttrace/semantic_conventions/http.md#http-server-definitions) of the matched virtual host.
Port identifier of the request target if it’s sent in absolute-form.
Port identifier of the Host header

[3]: If not default (80 for http scheme, 443 for https).

Metric: `http.server.request.size`

This metric is optional.

Name	Instrument Type	Unit (UCUM)	Description
`http.server.request.size`	Histogram	`By`	Measures the size of HTTP request messages (compressed).

Attribute	Type	Description	Examples	Requirement Level
`http.route`	string	The matched route (path template in the format used by the respective server framework). See note below [1]	`/users/:userID?`; `{controller}/{action}/{id?}`	Conditionally Required: If and only if it’s available
`http.request.method`	string	HTTP request method.	`GET`; `POST`; `HEAD`	Required
`http.response.status_code`	int	HTTP response status code.	`200`	Conditionally Required: If and only if one was received/sent.
`network.protocol.name`	string	OSI Application Layer or non-OSI equivalent. The value SHOULD be normalized to lowercase.	`amqp`; `http`; `mqtt`	Recommended
`network.protocol.version`	string	Version of the application layer protocol used. See note below. [2]	`3.1.1`	Recommended
`server.address`	string	Name of the local HTTP server that received the request. [3]	`example.com`	Required
`server.port`	int	Port of the local HTTP server that received the request. [4]	`80`; `8080`; `443`	Conditionally Required: [5]
`url.scheme`	string	The URI scheme component identifying the used protocol.	`http`; `https`	Required

[3]: Determined by using the first of the following that applies

The primary server nametrace/semantic_conventions/http.md#http-server-definitions) of the matched virtual host. MUST only include host identifier.
Host identifier of the request target if it’s sent in absolute-form.
Host identifier of the Host header

SHOULD NOT be set if only IP address is available and capturing name would require a reverse DNS lookup.

[4]: Determined by using the first of the following that applies

Port identifier of the primary server hosttrace/semantic_conventions/http.md#http-server-definitions) of the matched virtual host.
Port identifier of the request target if it’s sent in absolute-form.
Port identifier of the Host header

[5]: If not default (80 for http scheme, 443 for https).

Metric: `http.server.response.size`

This metric is optional.

Name	Instrument Type	Unit (UCUM)	Description
`http.server.response.size`	Histogram	`By`	Measures the size of HTTP response messages (compressed).

Attribute	Type	Description	Examples	Requirement Level
`http.route`	string	The matched route (path template in the format used by the respective server framework). See note below [1]	`/users/:userID?`; `{controller}/{action}/{id?}`	Conditionally Required: If and only if it’s available
`http.request.method`	string	HTTP request method.	`GET`; `POST`; `HEAD`	Required
`http.response.status_code`	int	HTTP response status code.	`200`	Conditionally Required: If and only if one was received/sent.
`network.protocol.name`	string	OSI Application Layer or non-OSI equivalent. The value SHOULD be normalized to lowercase.	`amqp`; `http`; `mqtt`	Recommended
`network.protocol.version`	string	Version of the application layer protocol used. See note below. [2]	`3.1.1`	Recommended
`server.address`	string	Name of the local HTTP server that received the request. [3]	`example.com`	Required
`server.port`	int	Port of the local HTTP server that received the request. [4]	`80`; `8080`; `443`	Conditionally Required: [5]
`url.scheme`	string	The URI scheme component identifying the used protocol.	`http`; `https`	Required

[3]: Determined by using the first of the following that applies

The primary server nametrace/semantic_conventions/http.md#http-server-definitions) of the matched virtual host. MUST only include host identifier.
Host identifier of the request target if it’s sent in absolute-form.
Host identifier of the Host header

SHOULD NOT be set if only IP address is available and capturing name would require a reverse DNS lookup.

[4]: Determined by using the first of the following that applies

Port identifier of the primary server hosttrace/semantic_conventions/http.md#http-server-definitions) of the matched virtual host.
Port identifier of the request target if it’s sent in absolute-form.
Port identifier of the Host header

[5]: If not default (80 for http scheme, 443 for https).

HTTP Client

Metric: `http.client.duration`

This metric is required.

This metric SHOULD be specified with ExplicitBucketBoundaries of [ 0, 0.005, 0.01, 0.025, 0.05, 0.075, 0.1, 0.25, 0.5, 0.75, 1, 2.5, 5, 7.5, 10 ].

Name	Instrument Type	Unit (UCUM)	Description
`http.client.duration`	Histogram	`s`	Measures the duration of outbound HTTP requests.

Attribute	Type	Description	Examples	Requirement Level
`http.request.method`	string	HTTP request method.	`GET`; `POST`; `HEAD`	Required
`http.response.status_code`	int	HTTP response status code.	`200`	Conditionally Required: If and only if one was received/sent.
`network.protocol.name`	string	OSI Application Layer or non-OSI equivalent. The value SHOULD be normalized to lowercase.	`amqp`; `http`; `mqtt`	Recommended
`network.protocol.version`	string	Version of the application layer protocol used. See note below. [1]	`3.1.1`	Recommended
`server.address`	string	Host identifier of the “URI origin” HTTP request is sent to. [2]	`example.com`	Required
`server.port`	int	Port identifier of the “URI origin” HTTP request is sent to. [3]	`80`; `8080`; `443`	Conditionally Required: [4]
`server.socket.address`	string	Physical server IP address or Unix socket address.	`10.5.3.2`	Recommended: If different than `server.address`.

[1]: network.protocol.version refers to the version of the protocol used and might be different from the protocol client’s version. If the HTTP client used has a version of 0.27.2, but sends HTTP version 1.1, this attribute should be set to 1.1.

[2]: Determined by using the first of the following that applies

Host identifier of the request target if it’s sent in absolute-form
Host identifier of the Host header

SHOULD NOT be set if capturing it would require an extra DNS lookup.

[3]: When request target is absolute URI, server.port MUST match URI port identifier, otherwise it MUST match Host header port identifier.

[4]: If not default (80 for http scheme, 443 for https).

Metric: `http.client.request.size`

This metric is optional.

Name	Instrument Type	Unit (UCUM)	Description
`http.client.request.size`	Histogram	`By`	Measures the size of HTTP request messages (compressed).

Attribute	Type	Description	Examples	Requirement Level
`http.request.method`	string	HTTP request method.	`GET`; `POST`; `HEAD`	Required
`http.response.status_code`	int	HTTP response status code.	`200`	Conditionally Required: If and only if one was received/sent.
`network.protocol.name`	string	OSI Application Layer or non-OSI equivalent. The value SHOULD be normalized to lowercase.	`amqp`; `http`; `mqtt`	Recommended
`network.protocol.version`	string	Version of the application layer protocol used. See note below. [1]	`3.1.1`	Recommended
`server.address`	string	Host identifier of the “URI origin” HTTP request is sent to. [2]	`example.com`	Required
`server.port`	int	Port identifier of the “URI origin” HTTP request is sent to. [3]	`80`; `8080`; `443`	Conditionally Required: [4]
`server.socket.address`	string	Physical server IP address or Unix socket address.	`10.5.3.2`	Recommended: If different than `server.address`.

[2]: Determined by using the first of the following that applies

Host identifier of the request target if it’s sent in absolute-form
Host identifier of the Host header

SHOULD NOT be set if capturing it would require an extra DNS lookup.

[3]: When request target is absolute URI, server.port MUST match URI port identifier, otherwise it MUST match Host header port identifier.

[4]: If not default (80 for http scheme, 443 for https).

Metric: `http.client.response.size`

This metric is optional.

Name	Instrument Type	Unit (UCUM)	Description
`http.client.response.size`	Histogram	`By`	Measures the size of HTTP response messages (compressed).

Attribute	Type	Description	Examples	Requirement Level
`http.request.method`	string	HTTP request method.	`GET`; `POST`; `HEAD`	Required
`http.response.status_code`	int	HTTP response status code.	`200`	Conditionally Required: If and only if one was received/sent.
`network.protocol.name`	string	OSI Application Layer or non-OSI equivalent. The value SHOULD be normalized to lowercase.	`amqp`; `http`; `mqtt`	Recommended
`network.protocol.version`	string	Version of the application layer protocol used. See note below. [1]	`3.1.1`	Recommended
`server.address`	string	Host identifier of the “URI origin” HTTP request is sent to. [2]	`example.com`	Required
`server.port`	int	Port identifier of the “URI origin” HTTP request is sent to. [3]	`80`; `8080`; `443`	Conditionally Required: [4]
`server.socket.address`	string	Physical server IP address or Unix socket address.	`10.5.3.2`	Recommended: If different than `server.address`.

[2]: Determined by using the first of the following that applies

Host identifier of the request target if it’s sent in absolute-form
Host identifier of the Host header

SHOULD NOT be set if capturing it would require an extra DNS lookup.

[3]: When request target is absolute URI, server.port MUST match URI port identifier, otherwise it MUST match Host header port identifier.

[4]: If not default (80 for http scheme, 443 for https).

Semantic Conventions for HTTP Metrics

HTTP Server

Metric: http.server.duration

Metric: http.server.active_requests

Metric: http.server.request.size

Metric: http.server.response.size

HTTP Client

Metric: http.client.duration

Metric: http.client.request.size

Metric: http.client.response.size

Metric: `http.server.duration`

Metric: `http.server.active_requests`

Metric: `http.server.request.size`

Metric: `http.server.response.size`

Metric: `http.client.duration`

Metric: `http.client.request.size`

Metric: `http.client.response.size`