github.com/open-telemetry/opentelemetry-collector-contrib/receiver/googlecloudpubsubreceiver

Google Pubsub Receiver

Status
Stability	beta: traces, logs, metrics
Distributions	observiq, sumo
Issues
Code Owners	@alexvanboxel

⚠️ This is a community-provided module. It has been developed and extensively tested at Collibra, but it is not officially supported by GCP.

This receiver gets OTLP messages from a Google Cloud Pubsub subscription.

The following configuration options are supported:

• project (Optional): The Google Cloud Project of the client connects to.
• subscription (Required): The subscription name to receive OTLP data from. The subscription name should be a fully qualified resource name (eg: projects/otel-project/subscriptions/otlp).
• encoding (Optional): The encoding that will be used to received data from the subscription. This can either be otlp_proto_trace, otlp_proto_metric, otlp_proto_log, cloud_logging, or raw_text (see encoding). This will only be used as a fallback, when no content-type attribute is present.
• compression (Optional): The compression that will be used on received data from the subscription. When set it can only be gzip. This will only be used as a fallback, when no content-encoding attribute is present.
• endpoint (Optional): Override the default Pubsub Endpoint, useful when connecting to the PubSub emulator instance or switching between global and regional service endpoints.
• insecure (Optional): allows performing “insecure” SSL connections and transfers, useful when connecting to a local emulator instance. Only has effect if Endpoint is not ""

receivers:
  googlecloudpubsub:
    project: otel-project
    subscription: projects/otel-project/subscriptions/otlp-logs
    encoding: raw_json

Encoding

You should not need to set the encoding of the subscription as the receiver will try to discover the type of the data by looking at the ce-type and content-type attributes of the message. Only when those attributes are not set must the encoding field in the configuration be set.

ce-type	ce-datacontenttype	encoding	description
org.opentelemetry.otlp.traces.v1	application/protobuf		Decode OTLP trace message
org.opentelemetry.otlp.metrics.v1	application/protobuf		Decode OTLP metric message
org.opentelemetry.otlp.logs.v1	application/json		Decode OTLP log message
-	-	otlp_proto_trace	Decode OTLP trace message
-	-	otlp_proto_metric	Decode OTLP trace message
-	-	otlp_proto_log	Decode OTLP trace message
-	-	cloud_logging	Decode Cloud Logging LogEntry message type
-	-	raw_text	Wrap in an OTLP log message

When the encoding configuration is set, the attributes on the message are ignored.

With cloud_logging, the receiver can be used to bring Cloud Logging messages into an OpenTelemetry pipeline. You'll first need to set up a logging sink with a Pub/Sub topic as its destination. Note that the cloud_logging integration is considered alpha as the semantic convention on some of the conversion are not stabilized yet.

With raw_text, the receiver can be used for ingesting arbitrary text message on a Pubsub subscription, wrapping them in OTLP Log messages, making it a convenient way to ingest raw log lines from Pubsub.

Pubsub subscription

The Google Cloud Pubsub receiver doesn't automatically create subscriptions, it expects the subscription to be created upfront. Security wise it's best to give the collector its own service account and give the subscription Pub/Sub Subscriber permission.

The subscription should also be of delivery type Pull.

Filtering

When the messages on the subscription are accompanied by the correct attributes and you only need a specific type in your pipeline, the messages can be filtered on the subscription saving on egress fees.

An example of filtering on trace message only:

attributes.ce-type = "org.opentelemetry.otlp.traces.v1"
AND
attributes.content-type = "application/protobuf"