RPC

• Remote Procedure Call (RPC) Attributes
• Deprecated RPC Attributes

Remote Procedure Call (RPC) Attributes

This document defines attributes for remote procedure calls.

Attribute	Type	Description	Examples	Stability
rpc.connect_rpc.error_code	string	The error codes of the Connect request. Error codes are always string values.	cancelled; unknown; invalid_argument
rpc.connect_rpc.request.metadata.<key>	string[]	Connect request metadata, <key> being the normalized Connect Metadata key (lowercase), the value being the metadata values. [1]	rpc.request.metadata.my-custom-metadata-attribute=["1.2.3.4", "1.2.3.5"]
rpc.connect_rpc.response.metadata.<key>	string[]	Connect response metadata, <key> being the normalized Connect Metadata key (lowercase), the value being the metadata values. [2]	rpc.response.metadata.my-custom-metadata-attribute=["attribute_value"]
rpc.grpc.request.metadata.<key>	string[]	gRPC request metadata, <key> being the normalized gRPC Metadata key (lowercase), the value being the metadata values. [3]	rpc.grpc.request.metadata.my-custom-metadata-attribute=["1.2.3.4", "1.2.3.5"]
rpc.grpc.response.metadata.<key>	string[]	gRPC response metadata, <key> being the normalized gRPC Metadata key (lowercase), the value being the metadata values. [4]	rpc.grpc.response.metadata.my-custom-metadata-attribute=["attribute_value"]
rpc.grpc.status_code	int	The numeric status code of the gRPC request.	0; 1; 2
rpc.jsonrpc.error_code	int	error.code property of response if it is an error response.	-32700; 100
rpc.jsonrpc.error_message	string	error.message property of response if it is an error response.	Parse error; User already exists
rpc.jsonrpc.request_id	string	id property of request or response. Since protocol allows id to be int, string, null or missing (for notifications), value is expected to be cast to string for simplicity. Use empty string in case of null value. Omit entirely if this is a notification.	10; request-7; ``
rpc.jsonrpc.version	string	Protocol version as in jsonrpc property of request/response. Since JSON-RPC 1.0 doesn’t specify this, the value can be omitted.	2.0; 1.0
rpc.message.compressed_size	int	Compressed size of the message in bytes.
rpc.message.id	int	MUST be calculated as two different counters starting from 1 one for sent messages and one for received message. [5]
rpc.message.type	string	Whether this is a received or sent message.	SENT; RECEIVED
rpc.message.uncompressed_size	int	Uncompressed size of the message in bytes.
rpc.method	string	The name of the (logical) method being called, must be equal to the $method part in the span name. [6]	exampleMethod
rpc.service	string	The full (logical) name of the service being called, including its package name, if applicable. [7]	myservice.EchoService
rpc.system	string	A string identifying the remoting system. See below for a list of well-known identifiers.	grpc; java_rmi; dotnet_wcf

[1]: Instrumentations SHOULD require an explicit configuration of which metadata values are to be captured. Including all request metadata values can be a security risk - explicit configuration helps avoid leaking sensitive information.

[2]: Instrumentations SHOULD require an explicit configuration of which metadata values are to be captured. Including all response metadata values can be a security risk - explicit configuration helps avoid leaking sensitive information.

[3]: Instrumentations SHOULD require an explicit configuration of which metadata values are to be captured. Including all request metadata values can be a security risk - explicit configuration helps avoid leaking sensitive information.

[4]: Instrumentations SHOULD require an explicit configuration of which metadata values are to be captured. Including all response metadata values can be a security risk - explicit configuration helps avoid leaking sensitive information.

[5]: This way we guarantee that the values will be consistent between different implementations.

[6]: This is the logical name of the method from the RPC interface perspective, which can be different from the name of any implementing method/function. The code.function attribute may be used to store the latter (e.g., method actually executing the call on the server side, RPC client stub method on the client side).

[7]: This is the logical name of the service from the RPC interface perspective, which can be different from the name of any implementing class. The code.namespace attribute may be used to store the latter (despite the attribute name, it may include a class name; e.g., class with method actually executing the call on the server side, RPC client stub class on the client side).

rpc.connect_rpc.error_code has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

Value	Description	Stability
aborted	aborted
already_exists	already_exists
cancelled	cancelled
data_loss	data_loss
deadline_exceeded	deadline_exceeded
failed_precondition	failed_precondition
internal	internal
invalid_argument	invalid_argument
not_found	not_found
out_of_range	out_of_range
permission_denied	permission_denied
resource_exhausted	resource_exhausted
unauthenticated	unauthenticated
unavailable	unavailable
unimplemented	unimplemented
unknown	unknown

rpc.grpc.status_code has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

Value	Description	Stability
0	OK
1	CANCELLED
2	UNKNOWN
3	INVALID_ARGUMENT
4	DEADLINE_EXCEEDED
5	NOT_FOUND
6	ALREADY_EXISTS
7	PERMISSION_DENIED
8	RESOURCE_EXHAUSTED
9	FAILED_PRECONDITION
10	ABORTED
11	OUT_OF_RANGE
12	UNIMPLEMENTED
13	INTERNAL
14	UNAVAILABLE
15	DATA_LOSS
16	UNAUTHENTICATED

rpc.message.type has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

Value	Description	Stability
RECEIVED	received
SENT	sent

rpc.system has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

Value	Description	Stability
apache_dubbo	Apache Dubbo
connect_rpc	Connect RPC
dotnet_wcf	.NET WCF
grpc	gRPC
java_rmi	Java RMI

Deprecated RPC Attributes

Deprecated rpc message attributes.

Attribute	Type	Description	Examples	Stability
message.compressed_size	int	Deprecated, use rpc.message.compressed_size instead.		Replaced by rpc.message.compressed_size.
message.id	int	Deprecated, use rpc.message.id instead.		Replaced by rpc.message.id.
message.type	string	Deprecated, use rpc.message.type instead.	SENT; RECEIVED	Replaced by rpc.message.type.
message.uncompressed_size	int	Deprecated, use rpc.message.uncompressed_size instead.		Replaced by rpc.message.uncompressed_size.

message.type has the following list of well-known values. If one of them applies, then the respective value MUST be used; otherwise, a custom value MAY be used.

Value	Description	Stability
RECEIVED	received
SENT	sent