The attributes described in this section are not specific to a particular operation but rather generic. They may be used in any Span they apply to. Particular operations may refer to or require some of these attributes.
These attributes may be used for any network related operation.
The net.peer.* attributes describe properties of the remote end of the network connection
(usually the transport-layer peer, e.g. the node to which a TCP connection was established),
while the net.host.* properties describe the local end.
In an ideal situation, not accounting for proxies, multiple IP addresses or host names,
the net.peer.* properties of a client are equal to the net.host.* properties of the server and vice versa.
| Attribute name | Notes and examples |
|---|---|
net.transport |
Transport protocol used. See note below. |
net.peer.ip |
Remote address of the peer (dotted decimal for IPv4 or RFC5952 for IPv6) |
net.peer.port |
Remote port number as an integer. E.g., 80. |
net.peer.name |
Remote hostname or similar, see note below. |
net.host.ip |
Like net.peer.ip but for the host IP. Useful in case of a multi-IP host. |
net.host.port |
Like net.peer.port but for the host port. |
net.host.name |
Local hostname or similar, see note below. |
This attribute should be set to the name of the transport layer protocol (or the relevant protocol below the "application protocol"). One of these strings should be used:
IP.TCPIP.UDPIP: Another IP-based protocol.Unix: Unix Domain socket. See note below.pipe: Named or anonymous pipe. See note below.inproc: Signals that there is only in-process communication not using a "real" network protocol in cases where network attributes would normally be expected. Usually all other network attributes can be left out in that case.other: Something else (not IP-based).
For Unix and pipe, since the connection goes over the file system instead of being directly to a known peer, net.peer.name is the only attribute that usually makes sense (see description of net.peer.name below).
For IP-based communication, the name should be a DNS host name.
For net.peer.name, this should be the name that was used to look up the IP address that was connected to
(i.e., matching net.peer.ip if that one is set; e.g., "example.com" if connecting to an URL https://example.com/foo).
If only the IP address but no host name is available, reverse-lookup of the IP may optionally be used to obtain it.
net.host.name should be the host name of the local host,
preferably the one that the peer used to connect for the current operation.
If that is not known, a public hostname should be preferred over a private one. However, in that case it may be redundant with information already contained in resources and may be left out.
It will usually not make sense to use reverse-lookup to obtain net.host.name, as that would result in static information that is better stored as resource information.
If net.transport is "unix" or "pipe", the absolute path to the file representing it should be used as net.peer.name (net.host.name doesn't make sense in that context).
If there is no such file (e.g., anonymous pipe),
the name should explicitly be set to the empty string to distinguish it from the case where the name is just unknown or not covered by the instrumentation.
This attribute may be used for any operation that accesses some remote service. Users can define what the name of a service is based on their particular semantics in their distributed system. Instrumentations SHOULD provide a way for users to configure this name.
| Attribute name | Notes and examples |
|---|---|
peer.service |
The service.name of the remote service. SHOULD be equal to the actual service.name resource attribute of the remote service if any. |
Examples of peer.service that users may specify:
- A Redis cache of auth tokens as
peer.service="AuthTokenCache". - A gRPC service
rpc.service="io.opentelemetry.AuthService"may be hosted in both a gateway,peer.service="ExternalApiService"and a backend,peer.service="AuthService".
These attributes may be used for any operation with an authenticated and/or authorized enduser.
| Attribute name | Notes and examples |
|---|---|
enduser.id |
Username or client_id extracted from the access token or Authorization header in the inbound request from outside the system. |
enduser.role |
Actual/assumed role the client is making the request under extracted from token or application security context. |
enduser.scope |
Scopes or granted authorities the client currently possesses extracted from token or application security context. The value would come from the scope associated with an OAuth 2.0 Access Token or an attribute value in a SAML 2.0 Assertion. |
These attributes describe the authenticated user driving the user agent making requests to the instrumented system. It is expected this information would be propagated unchanged from node-to-node within the system using the Correlation Context mechanism. These attributes should not be used to record system-to-system authentication attributes.
Examples of where the enduser.id value is extracted from:
| Authentication protocol | Field or description |
|---|---|
| HTTP Basic/Digest Authentication | username |
| OAuth 2.0 Bearer Token | OAuth 2.0 Client Identifier value from client_id for the OAuth 2.0 Client Credentials Grant flow and subject or username from get token info response for other flows using opaque tokens. |
| OpenID Connect 1.0 IDToken | sub |
| SAML 2.0 Assertion | urn:oasis:names:tc:SAML:2.0:assertion:Subject |
| Kerberos | PrincipalName |
| Framework | Field or description |
|---|---|
| JavaEE/JakartaEE Servlet | javax.servlet.http.HttpServletRequest.getUserPrincipal() |
| Windows Communication Foundation | ServiceSecurityContext.Current.PrimaryIdentity |
Given the sensitive nature of this information, SDKs and exporters SHOULD drop these attributes by default and then provide a configuration parameter to turn on retention for use cases where the information is required and would not violate any policies or regulations.