# Receiver Creator

<!-- status autogenerated section -->
| Status        |           |
| ------------- |-----------|
| Stability     | [alpha]: logs, traces   |
|               | [beta]: metrics   |
| Distributions | [contrib], [k8s] |
| Issues        | [![Open issues](https://img.shields.io/github/issues-search/open-telemetry/opentelemetry-collector-contrib?query=is%3Aissue%20is%3Aopen%20label%3Areceiver%2Freceivercreator%20&label=open&color=orange&logo=opentelemetry)](https://github.com/open-telemetry/opentelemetry-collector-contrib/issues?q=is%3Aopen+is%3Aissue+label%3Areceiver%2Freceivercreator) [![Closed issues](https://img.shields.io/github/issues-search/open-telemetry/opentelemetry-collector-contrib?query=is%3Aissue%20is%3Aclosed%20label%3Areceiver%2Freceivercreator%20&label=closed&color=blue&logo=opentelemetry)](https://github.com/open-telemetry/opentelemetry-collector-contrib/issues?q=is%3Aclosed+is%3Aissue+label%3Areceiver%2Freceivercreator) |
| [Code Owners](https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/CONTRIBUTING.md#becoming-a-code-owner)    | [@dmitryax](https://www.github.com/dmitryax) |
| Emeritus      | [@rmfitzpatrick](https://www.github.com/rmfitzpatrick) |

[alpha]: https://github.com/open-telemetry/opentelemetry-collector/blob/main/docs/component-stability.md#alpha
[beta]: https://github.com/open-telemetry/opentelemetry-collector/blob/main/docs/component-stability.md#beta
[contrib]: https://github.com/open-telemetry/opentelemetry-collector-releases/tree/main/distributions/otelcol-contrib
[k8s]: https://github.com/open-telemetry/opentelemetry-collector-releases/tree/main/distributions/otelcol-k8s
<!-- end autogenerated section -->

This receiver can instantiate other receivers at runtime based on whether
observed endpoints match a configured rule. To use the receiver creator, you
must first configure one or more
[observers](../../extension/observer/README.md) that will discover networked
endpoints that you may be interested in. The configured rules will be
evaluated for each endpoint discovered. If the rule evaluates to true then
the receiver for that rule will be started against the matched endpoint.

If you use the receiver creator in multiple pipelines of differing telemetry types,
but a given dynamically instantiated receiver doesn't support one of the pipeline's type,
it will effectively lead to a logged no-op that won't cause a collector service failure.

## Configuration

**watch_observers**

A list of observers previously defined to be run in the `extensions` section.
receiver_creator will watch for endpoints generated by these observers.

**receivers**

A map of receiver names (e.g. `redis/1`) to a template for when and how to
instantiate that receiver.

**receivers.&lt;receiver_type/id&gt;.rule**

Rule expression using [expvar
syntax](https://github.com/expr-lang/expr/blob/master/docs/language-definition.md).
Variables available are detailed below in [Rule
Expressions](#rule-expressions).

Note: The built-in `type` function introduced in v1.14.1 has been relocated to `typeOf`.

**receivers.&lt;receiver_type/id&gt;.config**

This is configuration that will be used when creating the receiver at
runtime.

This option can use static and dynamic configuration values. Static values
are normal YAML values. However, the value can also be dynamically constructed
from the discovered endpoint object. Dynamic values are surrounded by
backticks (\`). If a literal backtick is needed use \\` to escape it. Dynamic
values can be used with static values in which case they are concatenated.
For example:

```yaml
config:
   secure_url: https://`pod.labels["secure_host"]`
```

The value of `secure_url` will be `https://` concatenated with the value of
the `secure_host` label.

This can also be used when the discovered endpoint needs to be changed
dynamically. For instance, suppose the IP `1.2.3.4` is discovered without a
port but the port needs to be set inside endpoint. You could do:

```yaml
config:
   endpoint: '`endpoint`:8080'
```

If your target receiver provides an `endpoint` config field and you aren't
manually setting it like the above example, the observer endpoint target value
will automatically be sourced. If no `endpoint` field is available you are
required to specify any necessary fields.

**receivers.resource_attributes**

```yaml
resource_attributes:
  <endpoint type>:
    <attribute>: <attribute value>
```

This setting controls what resource attributes are set on telemetry emitted from the created receiver. These attributes can be set from [values in the endpoint](#rule-expressions) that was matched by the `rule`. These attributes vary based on the endpoint type. These defaults can be disabled by setting the attribute to be removed to an empty value. Note that the values can be dynamic and processed the same as in `config`.

Note that the backticks below are not typos--they indicate the value is set dynamically.

`type == "pod"`

| Resource Attribute | Default       |
|--------------------|---------------|
| k8s.pod.name       | \`name\`      |
| k8s.pod.uid        | \`uid\`       |
| k8s.namespace.name | \`namespace\` |

`type == "port"`

| Resource Attribute | Default           |
|--------------------|-------------------|
| k8s.pod.name       | \`pod.name\`      |
| k8s.pod.uid        | \`pod.uid\`       |
| k8s.namespace.name | \`pod.namespace\` |

`type == "pod.container"`

| Resource Attribute   | Default             |
|----------------------|---------------------|
| k8s.pod.name         | \`pod.name\`        |
| k8s.pod.uid          | \`pod.uid\`         |
| k8s.namespace.name   | \`pod.namespace\`   |
| container.name       | \`name\`            |
| k8s.container.name   | \`container_name\`  |
| container.image.name | \`container_image\` |
| container.id         | \`container_id\`    |

`type == "container"`

| Resource Attribute   | Default           |
|----------------------|-------------------|
| container.name       | \`name\`          |
| container.image.name | \`image\`         |

`type == "hostport"`

None

`type == "k8s.service"`

| Resource Attribute | Default           |
|--------------------|-------------------|
| k8s.namespace.name | \`namespace\`     |

`type == "k8s.node"`

| Resource Attribute | Default           |
|--------------------|-------------------|
| k8s.node.name      | \`name\`          |
| k8s.node.uid       | \`uid\`           |

`type == "k8s.ingress"`

| Resource Attribute | Default           |
|--------------------|-------------------|
| k8s.namespace.name | \`namespace\`     |

See `redis/2` in [examples](#examples).


**receivers.&lt;receiver_type/id&gt;.resource_attributes**

```yaml
receivers:
  <receiver_type>:
    resource_attributes:
      <attribute>: <attribute string value>
```

Similar to the per-endpoint type `resource_attributes` described above but for individual receiver instances. Duplicate attribute entries (including the empty string) in this receiver-specific mapping take precedence. These attribute values also support expansion from endpoint environment content. At this time their values must be strings.

## Rule Expressions

Each rule must start with `type == ("pod"|"port"|"pod.container"|"hostport"|"container"|"k8s.service"|"k8s.node"|"k8s.ingress") &&` such that the rule matches
only one endpoint type. Depending on the type of endpoint the rule is
targeting it will have different variables available.

### Pod

| Variable    | Description                       | Data Type                     |
|-------------|-----------------------------------|-------------------------------|
| type        | `"pod"`                           | String                        |
| id          | ID of source endpoint             | String                        |
| name        | name of the pod                   | String                        |
| namespace   | namespace of the pod              | String                        |
| uid         | unique id of the pod              | String                        |
| labels      | map of labels set on the pod      | Map with String key and value |
| annotations | map of annotations set on the pod | Map with String key and value |

### Port

| Variable        | Description                             | Data Type                     |
|-----------------|-----------------------------------------|-------------------------------|
| type            | `"port"`                                | String                        |
| id              | ID of source endpoint                   | String                        |
| name            | container port name                     | String                        |
| port            | port number                             | Integer                       |
| protocol        | The transport protocol ("TCP" or "UDP") | String                        |
| pod.name        | name of the owning pod                  | String                        |
| pod.namespace   | namespace of the pod                    | String                        |
| pod.uid         | unique id of the pod                    | String                        |
| pod.labels      | map of labels of the owning pod         | Map with String key and value |
| pod.annotations | map of annotations of the owning pod    | Map with String key and value |

### Pod Container

| Variable        | Description                          | Data Type                     |
|-----------------|--------------------------------------|-------------------------------|
| type            | `"pod.container"`                    | String                        |
| id              | ID of source endpoint                | String                        |
| container_name  | container name                       | String                        |
| container_id    | container id                         | String                        |
| container_image | container image                      | String                        |
| pod.name        | name of the owning pod               | String                        |
| pod.namespace   | namespace of the pod                 | String                        |
| pod.uid         | unique id of the pod                 | String                        |
| pod.labels      | map of labels of the owning pod      | Map with String key and value |
| pod.annotations | map of annotations of the owning pod | Map with String key and value |

### Host Port

| Variable      | Description                                      | Data Type                     |
|---------------|--------------------------------------------------|-------------------------------|
| type          | `"hostport"`                                     | String                        |
| id            | ID of source endpoint                            | String                        |
| process_name  | Name of the process                              | String                        |
| command       | Command line with the used to invoke the process | String                        |
| is_ipv6       | true if endpoint is IPv6, otherwise false        | Boolean                       |
| port          | Port number                                      | Integer                       |
| transport     | The transport protocol ("TCP" or "UDP")          | String                        |

### Container

| Variable       | Description                                                       | Data Type                     |
|----------------|-------------------------------------------------------------------|-------------------------------|
| type           | `"container"`                                                     | String                        |
| id             | ID of source endpoint                                             | String                        |
| name           | Primary name of the container                                     | String                        |
| image          | Name of the container image                                       | String                        |
| port           | Exposed port of the container                                     | Integer                       |
| alternate_port | Exposed port accessed through redirection, such as a mapped port  | Integer                       |
| command        | The command used to invoke the process of the container           | String                        |
| container_id   | ID of the container                                               | String                        |
| host           | Hostname or IP of the underlying host the container is running on | String                        |
| transport      | Transport protocol used by the endpoint (TCP or UDP)              | String                        |
| labels         | User-specified metadata labels on the container                   | Map with String key and value |

### Kubernetes Service

| Variable       | Description                                                                           | Data Type                     |
|----------------|---------------------------------------------------------------------------------------|-------------------------------|
| type           | `"k8s.service"`                                                                       | String                        |
| id             | ID of source endpoint                                                                 | String                        |
| name           | The name of the Kubernetes service                                                    | String                        |
| namespace      | The namespace of the service                                                          | String                        |
| uid            | The unique ID for the service                                                         | String                        |
| labels         | The map of labels set on the service                                                  | Map with String key and value |
| annotations    | The map of annotations set on the service                                             | Map with String key and value |
| service_type   | The type of the kubernetes service: ClusterIP, NodePort, LoadBalancer, ExternalName   | String                        |
| cluster_ip     | The cluster IP assigned to the service                                                | String                        |

### Kubernetes Ingress

| Variable       | Description                                                                           | Data Type                     |
|----------------|---------------------------------------------------------------------------------------|-------------------------------|
| type           | `"k8s.ingress"`                                                                       | String                        |
| id             | ID of source endpoint                                                                 | String                        |
| name           | The name of the Kubernetes ingress                                                    | String                        |
| namespace      | The namespace of the ingress                                                          | String                        |
| uid            | The unique ID for the ingress                                                         | String                        |
| labels         | The map of labels set on the ingress                                                  | Map with String key and value |
| annotations    | The map of annotations set on the ingress                                             | Map with String key and value |
| scheme         | Scheme represents whether the ingress path is accessible via HTTPS or HTTP.           | String                        |
| host           | Host is the FQDN that map to backends                                                 | String                        |
| path           | Path that map requests to backends                                                    | String                        |

### Kubernetes Node

| Variable              | Description                                                          | Data Type                     |
|-----------------------|----------------------------------------------------------------------|-------------------------------|
| type                  | `"k8s.node"`                                                         | String                        |
| id                    | ID of source endpoint                                                | String                        |
| name                  | The name of the Kubernetes node                                      | String                        |
| uid                   | The unique ID for the node                                           | String                        |
| hostname              | The node's hostname as reported by its Status object                 | String                        |
| external_ip           | The node's external IP address as reported by its Status object      | String                        |
| internal_ip           | The node's internal IP address as reported by its Status object      | String                        |
| external_dns          | The node's external DNS record as reported by its Status object      | String                        |
| internal_dns          | The node's internal DNS record as reported by its Status object      | String                        |
| annotations           | A key-value map of non-identifying, user-specified node metadata     | Map with String key and value |
| labels                | A key-value map of user-specified node metadata                      | Map with String key and value |
| kubelet_endpoint_port | The node Status object's DaemonEndpoints.KubeletEndpoint.Port value  | Integer                       |

## Examples

```yaml
extensions:
  # Configures the Kubernetes observer to watch for pod start and stop events.
  k8s_observer:
    observe_nodes: true
    observe_services: true
    observe_ingresses: true
  host_observer:

receivers:
  receiver_creator/1:
    # Name of the extensions to watch for endpoints to start and stop.
    watch_observers: [k8s_observer]
    receivers:
      prometheus_simple:
        # Configure prometheus scraping if standard prometheus annotations are set on the pod.
        rule: type == "pod" && annotations["prometheus.io/scrape"] == "true"
        config:
          metrics_path: '`"prometheus.io/path" in annotations ? annotations["prometheus.io/path"] : "/metrics"`'
          endpoint: '`endpoint`:`"prometheus.io/port" in annotations ? annotations["prometheus.io/port"] : 9090`'
        resource_attributes:
          an.attribute: a.value
          # Dynamic configuration values
          app.version: '`labels["app_version"]`'

      redis/1:
        # If this rule matches an instance of this receiver will be started.
        rule: type == "port" && port == 6379
        config:
          # Static receiver-specific config.
          password: secret
          # Dynamic configuration value.
          collection_interval: '`pod.annotations["collection_interval"]`'

      redis/2:
        # Set a resource attribute based on endpoint value.
        rule: type == "port" && port == 6379

      sqlserver:
        rule: type == "port" && pod.name matches "(?i)mssql"
        config:
          server: '`host`'
          port: '`port`'
          username: sa
          password: password

    resource_attributes:
      # Dynamic configuration values, overwriting default attributes`
      pod:
        service.name: '`labels["service_name"]`'
        app: '`labels["app"]`'
      port:
        service.name: '`pod.labels["service_name"]`'
        app: '`pod.labels["app"]`'
  receiver_creator/2:
    # Name of the extensions to watch for endpoints to start and stop.
    watch_observers: [host_observer]
    receivers:
      redis/on_host:
        # If this rule matches an instance of this receiver will be started.
        rule: type == "port" && port == 6379 && is_ipv6 == true
        resource_attributes:
          service.name: redis_on_host
  receiver_creator/3:
    watch_observers: [k8s_observer]
    receivers:
      kubeletstats:
        rule: type == "k8s.node"
        config:
          auth_type: serviceAccount
          collection_interval: 10s
          endpoint: '`endpoint`:`kubelet_endpoint_port`'
          extra_metadata_labels:
            - container.id
          metric_groups:
            - container
            - pod
            - node
      httpcheck:
        # Configure probing if standard prometheus annotations are set on the pod.
        rule: type == "k8s.service" && annotations["prometheus.io/probe"] == "true"
        config:
          targets:
          - endpoint: 'http://`endpoint`:`"prometheus.io/port" in annotations ? annotations["prometheus.io/port"] : 9090``"prometheus.io/path" in annotations ? annotations["prometheus.io/path"] : "/health"`'
            method: GET
          collection_interval: 10s
  receiver_creator/4:
    watch_observers: [k8s_observer]
    receivers:
      httpcheck:
        # Configure probing if standard prometheus annotations are set on the pod.
        rule: type == "k8s.ingress" && annotations["prometheus.io/probe"] == "true"
        config:
          targets:
          - endpoint: '`scheme`://`endpoint`:`port``"prometheus.io/path" in annotations ? annotations["prometheus.io/path"] : "/health"`'
            method: GET
          collection_interval: 10s
  receiver_creator/logs:
    watch_observers: [ k8s_observer ]
    receivers:
      filelog/busybox:
        rule: type == "pod.container" && container_name == "busybox"
        config:
          include:
            - /var/log/pods/`pod.namespace`_`pod.name`_`pod.uid`/`container_name`/*.log
          include_file_name: false
          include_file_path: true
          operators:
            - id: container-parser
              type: container
            - type: add
              field: attributes.log.template
              value: busybox
      filelog/lazybox:
        rule: type == "pod.container" && container_name == "lazybox"
        config:
          include:
            - /var/log/pods/`pod.namespace`_`pod.name`_`pod.uid`/`container_name`/*.log
          include_file_name: false
          include_file_path: true
          operators:
            - id: container-parser
              type: container
            - type: add
              field: attributes.log.template
              value: lazybox

processors:
  exampleprocessor:

exporters:
  exampleexporter:

service:
  pipelines:
    metrics:
      receivers: [receiver_creator/1, receiver_creator/2, receiver_creator/3, receiver_creator/4]
      processors: [exampleprocessor]
      exporters: [exampleexporter]
    logs:
      receivers: [receiver_creator/logs]
      processors: [exampleprocessor]
      exporters: [exampleexporter]
  extensions: [k8s_observer, host_observer]
```

The full list of settings exposed for this receiver are documented [here](./config.go)
with detailed sample configurations [here](./testdata/config.yaml).


## Generate receiver configurations from provided Hints

Note: When hints feature is enabled if hints are present for an endpoint no receiver templates will be evaluated.

Currently this feature is only supported for K8s environments and the `k8sobserver`.

The discovery feature for K8s is enabled with the following setting:

```yaml
receiver_creator/metrics:
  watch_observers: [ k8s_observer ]
  discovery:
     enabled: true
     # Define which receivers should be ignored when provided through annotations
     # ignore_receivers: []
```

Find bellow the supported annotations that user can define to automatically enable receivers to start collecting metrics signals from the target Pods/containers.

### Supported metrics annotations

#### Enable/disable discovery

`io.opentelemetry.discovery.metrics/enabled` (Required. `"true"` or `"false"`)

#### Define scraper

`io.opentelemetry.discovery.metrics/scraper` (example: `"nginx"`)


#### Define configuration

`io.opentelemetry.discovery.metrics/config`

For `"endpoint"` setting specifically, it sticks to urls that include
```"`endpoint`"``` as it comes from the Port endpoint which is
in form of `pod_ip:container_port`. This is to ensure that each Pod can only
generate configuration that targets itself and not others.
If no endpoint is provided the Pod's endpoint will be used (in form of `pod_ip:container_port`).

**Example:**

```yaml
io.opentelemetry.discovery.metrics/config: |
  endpoint: "http://`endpoint`/nginx_status"
  collection_interval: "20s"
  initial_delay: "20s"
  read_buffer_size: "10"
  xyz: "abc"
```


#### Support multiple target containers

Users can target the annotation to a specific container by suffixing it with the name of the port that container exposes:
`io.opentelemetry.discovery.metrics.<container_port>/config`.
For example:
```yaml
io.opentelemetry.discovery.metrics.80/config: |
  endpoint: "http://`endpoint`/nginx_status"
```
where `80` is the port that the target container exposes.

If a Pod is annotated with both container level hints and pod level hints the container level hints have priority and
the Pod level hints are used as a fallback (see detailed example bellow).

The current implementation relies on the implementation of `k8sobserver` extension and specifically
the [pod_endpoint](https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/v0.111.0/extension/observer/k8sobserver/pod_endpoint.go).
The hints are evaluated per container by extracting the annotations from each [`Port` endpoint](#Port) that is emitted. 



### Examples

#### Metrics example

Collector's configuration:
```yaml
receivers:
  receiver_creator/metrics:
    watch_observers: [ k8s_observer ]
    discovery:
      enabled: true
    receivers:

service:
  extensions: [ k8s_observer]
  pipelines:
    metrics:
      receivers: [ receiver_creator ]
      processors: []
      exporters: [ debug ]
```

Target Pod annotated with hints:

```yaml
apiVersion: v1
kind: ConfigMap
metadata:
  name: nginx-conf
data:
  nginx.conf: |
    user  nginx;
    worker_processes  1;
    error_log  /dev/stderr warn;
    pid        /var/run/nginx.pid;
    events {
      worker_connections  1024;
    }
    http {
      include       /etc/nginx/mime.types;
      default_type  application/octet-stream;

      log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                        '$status $body_bytes_sent "$http_referer" '
                        '"$http_user_agent" "$http_x_forwarded_for"';
      access_log  /dev/stdout main;
      server {
          listen 80;
          server_name localhost;

          location /nginx_status {
              stub_status on;
          }
      }
      include /etc/nginx/conf.d/*;
    }
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: redis-deployment
  labels:
    app: redis
spec:
  replicas: 1
  selector:
    matchLabels:
      app: redis
  template:
    metadata:
      labels:
        app: redis
      annotations:
        # redis container port metrics hints
        io.opentelemetry.discovery.metrics.6379/enabled: "true"
        io.opentelemetry.discovery.metrics.6379/scraper: redis
        io.opentelemetry.discovery.metrics.6379/config: |
          collection_interval: "20s"
          timeout: "10s"

        # nginx container port metrics hints
        io.opentelemetry.discovery.metrics.80/enabled: "true"
        io.opentelemetry.discovery.metrics.80/scraper: nginx
        io.opentelemetry.discovery.metrics.80/config: |
          endpoint: "http://`endpoint`/nginx_status"
          collection_interval: "30s"
          timeout: "20s"
    spec:
      volumes:
        - name: nginx-conf
          configMap:
            name: nginx-conf
            items:
              - key: nginx.conf
                path: nginx.conf
      containers:
        - name: webserver
          image: nginx:latest
          ports:
            - containerPort: 80
              name: webserver
          volumeMounts:
            - mountPath: /etc/nginx/nginx.conf
              readOnly: true
              subPath: nginx.conf
              name: nginx-conf
        - image: redis
          imagePullPolicy: IfNotPresent
          name: redis
          ports:
            - name: redis
              containerPort: 6379
              protocol: TCP
```