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# Resource Semantic Conventions

**Status**: [Mixed][DocumentStatus]

This document defines standard attributes for resources. These attributes are typically used in the [Resource](https://github.com/open-telemetry/opentelemetry-specification/tree/v1.26.0/specification/resource/sdk.md) and are also recommended to be used anywhere else where there is a need to describe a resource in a consistent manner. The majority of these attributes are inherited from
[OpenCensus Resource standard](https://github.com/census-instrumentation/opencensus-specs/blob/master/resource/StandardResources.md).

<!-- Re-generate TOC with `markdown-toc --no-first-h1 -i` -->

<!-- toc -->

- [TODOs](#todos)
- [Document Conventions](#document-conventions)
- [Attributes with Special Handling](#attributes-with-special-handling)
  * [Semantic Attributes with Dedicated Environment Variable](#semantic-attributes-with-dedicated-environment-variable)
- [Semantic Attributes with SDK-provided Default Value](#semantic-attributes-with-sdk-provided-default-value)
- [Service](#service)
- [Service (Experimental)](#service-experimental)
- [Telemetry SDK](#telemetry-sdk)
- [Telemetry SDK (Experimental)](#telemetry-sdk-experimental)
- [Compute Unit](#compute-unit)
- [Compute Instance](#compute-instance)
- [Environment](#environment)
- [Version attributes](#version-attributes)
- [Cloud-Provider-Specific Attributes](#cloud-provider-specific-attributes)

<!-- tocstop -->

## TODOs

* Add more compute units: AppEngine unit, etc.
* Add Web Browser.
* Decide if lower case strings only.
* Consider to add optional/required for each attribute and combination of attributes
  (e.g when supplying a k8s resource all k8s may be required).

## Document Conventions

**Status**: [Stable][DocumentStatus]

Attributes are grouped logically by the type of the concept that they described. Attributes in the same group have a common prefix that ends with a dot. For example all attributes that describe Kubernetes properties start with "k8s."

See [Attribute Requirement Levels](https://github.com/open-telemetry/opentelemetry-specification/tree/v1.26.0/specification/common/attribute-requirement-level.md) for details on when attributes
should be included.

## Attributes with Special Handling

**Status**: [Stable][DocumentStatus]

Given their significance some resource attributes are treated specifically as described below.

### Semantic Attributes with Dedicated Environment Variable

These are the attributes which MAY be configurable via a dedicated environment variable
as specified in [OpenTelemetry Environment Variable Specification](https://github.com/open-telemetry/opentelemetry-specification/tree/v1.26.0/specification/configuration/sdk-environment-variables.md):

- [`service.name`](#service)

## Semantic Attributes with SDK-provided Default Value

These are the attributes which MUST be provided by the SDK
as specified in the [Resource SDK specification](https://github.com/open-telemetry/opentelemetry-specification/tree/v1.26.0/specification/resource/sdk.md#sdk-provided-resource-attributes):

- [`service.name`](#service)
- [`telemetry.sdk` group](#telemetry-sdk)

## Service

**Status**: [Stable][DocumentStatus]

**type:** `service`

**Description:** A service instance.

<!-- semconv service -->
| Attribute  | Type | Description  | Examples  | Requirement Level |
|---|---|---|---|---|
| `service.name` | string | Logical name of the service. [1] | `shoppingcart` | Required |
| `service.version` | string | The version string of the service API or implementation. The format is not defined by these conventions. | `2.0.0`; `a01dbef8a` | Recommended |

**[1]:** MUST be the same for all instances of horizontally scaled services. If the value was not specified, SDKs MUST fallback to `unknown_service:` concatenated with [`process.executable.name`](process.md#process), e.g. `unknown_service:bash`. If `process.executable.name` is not available, the value MUST be set to `unknown_service`.
<!-- endsemconv -->

## Service (Experimental)

**Status**: [Experimental][DocumentStatus]

**type:** `service`

**Description:** Additions to service instance.

<!-- semconv service_experimental -->
| Attribute  | Type | Description  | Examples  | Requirement Level |
|---|---|---|---|---|
| `service.instance.id` | string | The string ID of the service instance. [1] | `my-k8s-pod-deployment-1`; `627cc493-f310-47de-96bd-71410b7dec09` | Recommended |
| `service.namespace` | string | A namespace for `service.name`. [2] | `Shop` | Recommended |

**[1]:** MUST be unique for each instance of the same `service.namespace,service.name` pair (in other words `service.namespace,service.name,service.instance.id` triplet MUST be globally unique). The ID helps to distinguish instances of the same service that exist at the same time (e.g. instances of a horizontally scaled service). It is preferable for the ID to be persistent and stay the same for the lifetime of the service instance, however it is acceptable that the ID is ephemeral and changes during important lifetime events for the service (e.g. service restarts). If the service has no inherent unique ID that can be used as the value of this attribute it is recommended to generate a random Version 1 or Version 4 RFC 4122 UUID (services aiming for reproducible UUIDs may also use Version 5, see RFC 4122 for more recommendations).

**[2]:** A string value having a meaning that helps to distinguish a group of services, for example the team name that owns a group of services. `service.name` is expected to be unique within the same namespace. If `service.namespace` is not specified in the Resource then `service.name` is expected to be unique for all services that have no explicit namespace defined (so the empty/unspecified namespace is simply one more valid namespace). Zero-length namespace string is assumed equal to unspecified namespace.
<!-- endsemconv -->

Note: `service.namespace` and `service.name` are not intended to be concatenated for the purpose of forming a single globally unique name for the service. For example the following 2 sets of attributes actually describe 2 different services (despite the fact that the concatenation would result in the same string):

```
# Resource attributes that describes a service.
namespace = Company.Shop
service.name = shoppingcart
```

```
# Another set of resource attributes that describe a different service.
namespace = Company
service.name = Shop.shoppingcart
```

## Telemetry SDK

**Status**: [Stable][DocumentStatus]

**type:** `telemetry.sdk`

**Description:** The telemetry SDK used to capture data recorded by the instrumentation libraries.

<!-- semconv telemetry -->
| Attribute  | Type | Description  | Examples  | Requirement Level |
|---|---|---|---|---|
| `telemetry.sdk.language` | string | The language of the telemetry SDK. | `cpp` | Required |
| `telemetry.sdk.name` | string | The name of the telemetry SDK as defined above. [1] | `opentelemetry` | Required |
| `telemetry.sdk.version` | string | The version string of the telemetry SDK. | `1.2.3` | Required |

**[1]:** The OpenTelemetry SDK MUST set the `telemetry.sdk.name` attribute to `opentelemetry`.
If another SDK, like a fork or a vendor-provided implementation, is used, this SDK MUST set the
`telemetry.sdk.name` attribute to the fully-qualified class or module name of this SDK's main entry point
or another suitable identifier depending on the language.
The identifier `opentelemetry` is reserved and MUST NOT be used in this case.
All custom identifiers SHOULD be stable across different versions of an implementation.

`telemetry.sdk.language` 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 |
|---|---|
| `cpp` | cpp |
| `dotnet` | dotnet |
| `erlang` | erlang |
| `go` | go |
| `java` | java |
| `nodejs` | nodejs |
| `php` | php |
| `python` | python |
| `ruby` | ruby |
| `rust` | rust |
| `swift` | swift |
| `webjs` | webjs |
<!-- endsemconv -->

## Telemetry SDK (Experimental)

**Status**: [Experimental][DocumentStatus]

**type:** `telemetry.sdk`

**Description:** Additions to the telemetry SDK.

<!-- semconv telemetry_experimental -->
| Attribute  | Type | Description  | Examples  | Requirement Level |
|---|---|---|---|---|
| `telemetry.distro.name` | string | The name of the auto instrumentation agent or distribution, if used. [1] | `parts-unlimited-java` | Recommended |
| `telemetry.distro.version` | string | The version string of the auto instrumentation agent or distribution, if used. | `1.2.3` | Recommended |

**[1]:** Official auto instrumentation agents and distributions SHOULD set the `telemetry.distro.name` attribute to
a string starting with `opentelemetry-`, e.g. `opentelemetry-java-instrumentation`.
<!-- endsemconv -->

## Compute Unit

**Status**: [Experimental][DocumentStatus]

Attributes defining a compute unit (e.g. Container, Process, Function as a Service):

- [Container](./container.md)
- [Function as a Service](./faas.md)
- [Process](./process.md)
- [Web engine](./webengine.md)

## Compute Instance

**Status**: [Experimental][DocumentStatus]

Attributes defining a computing instance (e.g. host):

- [Host](./host.md)

## Environment

**Status**: [Experimental][DocumentStatus]

Attributes defining a running environment (e.g. Operating System, Cloud, Data Center, Deployment Service):

- [Operating System](./os.md)
- [Device](./device.md)
- [Cloud](./cloud.md)
- Deployment:
  - [Deployment Environment](./deployment-environment.md)
  - [Kubernetes](./k8s.md)
- [Browser](./browser.md)

## Version attributes

**Status**: [Stable][DocumentStatus]

Version attributes, such as `service.version`, are values of type `string`. They are
the exact version used to identify an artifact. This may be a semantic version, e.g., `1.2.3`, git hash, e.g.,
`8ae73a`, or an arbitrary version string, e.g., `0.1.2.20210101`, whatever was used when building the artifact.

## Cloud-Provider-Specific Attributes

**Status**: [Experimental][DocumentStatus]

Attributes that are only applicable to resources from a specific cloud provider. Currently, these
resources can only be defined for providers listed as a valid `cloud.provider` in
[Cloud](./cloud.md) and below. Provider-specific attributes all reside in the `cloud-provider` directory.
Valid cloud providers are:

- [Alibaba Cloud](https://www.alibabacloud.com/) (`alibaba_cloud`)
- [Amazon Web Services](https://aws.amazon.com/) ([`aws`](cloud-provider/aws/README.md))
- [Google Cloud Platform](https://cloud.google.com/) ([`gcp`](cloud-provider/gcp/README.md))
- [Microsoft Azure](https://azure.microsoft.com/) (`azure`)
- [Tencent Cloud](https://www.tencentcloud.com/) (`tencent_cloud`)
- [Heroku dyno](./cloud-provider/heroku.md)

[DocumentStatus]: https://github.com/open-telemetry/opentelemetry-specification/tree/v1.26.0/specification/document-status.md
