[exporter/datadog] Update metrics export to use datadog-api-client-go instead of Zorkian

[songy23]

Description:

Migrate metrics export in datadogexporter from gopkg.in/zorkian/go-datadog-api.v2 to github.com/DataDog/datadog-api-client-go/v2/api/datadog because the Zorkian library is deprecated. This is guarded by feature gate and can be disabled by adding CLI flag --feature-gates=-exporter.datadogexporter.metricexportnativeclient

Link to tracking Issue:

Fixes #16776.
Fixes #6944.

Testing:

Tested in the staging environment, verified OTLP metrics are properly displayed on Datadog UI.

Documentation:

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[mx-psi]

When would we get endpoint == ""? What should happen in that situation?

[songy23]

This endpoint is from config Metrics.TCPAddr.Endpoint, it's an optional parameter so it can be left unspecified (even the official doc doesn't specify it: https://docs.datadoghq.com/opentelemetry/otel_collector_datadog_exporter/?tab=onahost#setting-up-the-otel-collector-with-the-datadog-exporter).

If it's empty, the datadog exporter should use the default metric endpoint from datadog.NewConfiguration(): https://github.com/DataDog/datadog-api-client-go/blob/206cab2100541c0ed9562e8cca96394b707cbf5c/api/datadog/configuration.go#L102. We don't want to override that value with empty.

[mx-psi]

If left unspecified, the endpoint will be set based on the site

opentelemetry-collector-contrib/exporter/datadogexporter/config.go

Lines 491 to 500 in e46477e

	// If an endpoint is not explicitly set, override it based on the site.
	if !configMap.IsSet("metrics::endpoint") {
	c.Metrics.TCPAddr.Endpoint = fmt.Sprintf("https://api.%s", c.API.Site)
	}
	if !configMap.IsSet("traces::endpoint") {
	c.Traces.TCPAddr.Endpoint = fmt.Sprintf("https://trace.agent.%s", c.API.Site)
	}
	if !configMap.IsSet("logs::endpoint") {
	c.Logs.TCPAddr.Endpoint = fmt.Sprintf("https://http-intake.logs.%s", c.API.Site)
	}

, so I don't think we would get this in practice, unless someone explicitly sets endpoint: "".

I have a slight preference to make the whole thing fail if the endpoint is empty, but since I don't feel strongly I will approve this and merge after you see this if you think it's better this way.

[songy23]

Sounds good, I'd prefer to do the validation in a follow-up PR since that's a fairly independent change.

[mx-psi]

If left unspecified, the endpoint will be set based on the site

opentelemetry-collector-contrib/exporter/datadogexporter/config.go

Lines 491 to 500 in e46477e

	// If an endpoint is not explicitly set, override it based on the site.
	if !configMap.IsSet("metrics::endpoint") {
	c.Metrics.TCPAddr.Endpoint = fmt.Sprintf("https://api.%s", c.API.Site)
	}
	if !configMap.IsSet("traces::endpoint") {
	c.Traces.TCPAddr.Endpoint = fmt.Sprintf("https://trace.agent.%s", c.API.Site)
	}
	if !configMap.IsSet("logs::endpoint") {
	c.Logs.TCPAddr.Endpoint = fmt.Sprintf("https://http-intake.logs.%s", c.API.Site)
	}

, so I don't think we would get this in practice, unless someone explicitly sets endpoint: "".

I have a slight preference to make the whole thing fail if the endpoint is empty, but since I don't feel strongly I will approve this and merge after you see this if you think it's better this way.

[songy23]

Thanks for the review!