junit2otlp

junit2otlp

This simple CLI, written in Go, is sending jUnit metrics to a back-end using Open Telemetry.

Inspired by https://github.com/axw/test2otlp, which sends traces and spans for go test JSON events as they occur.

Background

As jUnit represents a de-facto standard for test results in every programming language, this tool consumes the XML files produced by the test runner (or a tool converting to xUnit format), sending metrics to one or more open-source or commercial back-ends with Open Telemetry.

Supported CI runners

This tool will work in the context of a CI runner, such as a Github action, a Jenkins job, a Gitlab runner, or even a local execution. This is important because it will use the context of the CI execution to infer the attributes to be added to the OpenTelemetry traces and spans.

In particular the order of evaluation to detect the right execution context is the following:

 Local execution > Github action > Jenkins multibranch pipeline > Gitlab runner > NIL

Local execution

It reads the environment variables that are avaible in the context of a local execution, representing the fallback if no context is discovered:

// FromLocal returns an SCM context for local, using TARGET_BRANCH and BRANCH as the variables controlling
// if the SCM context represents a change request. BRANCH is mandatory, otherwise an empty context will be retrieved.
// If TARGET_BRANCH is not empty, it will represent a change request
func FromLocal() *ScmContext {
	baseRef := os.Getenv("TARGET_BRANCH")
	headRef := os.Getenv("BRANCH")
	if headRef == "" {
		return nil
	}

	isPR := (baseRef != "")

	return &ScmContext{
		ChangeRequest: isPR,
		Commit:        "",
		Branch:        headRef,
		Provider:      "",
		TargetBranch:  baseRef,
	}
}

Github Actions

It reads the environment variables that are avaible in the context of a Github Action execution:

// FromGithub returns an SCM context for Github, reading the right environment variables, as described
// in their docs
func FromGithub() *ScmContext {
	if os.Getenv("GITHUB_SHA") == "" {
		return nil
	}

	sha := os.Getenv("GITHUB_SHA")
	branchName := os.Getenv("GITHUB_REF_NAME")
	baseRef := os.Getenv("GITHUB_BASE_REF") // only present for pull requests on Github Actions
	headRef := os.Getenv("GITHUB_HEAD_REF") // only present for pull requests on Github Actions

	isChangeRequest := (baseRef != "" && headRef != "")

	return &ScmContext{
		ChangeRequest: isChangeRequest,
		Commit:        sha,
		Branch:        branchName,
		Provider:      "Github",
		TargetBranch:  baseRef,
	}
}

Jenkins multibranch pipelines

It reads the environment variables that are avaible in the context of a Jenkins multibranch pipeline execution:

// FromJenkins returns an SCM context for Jenkins, reading the right environment variables, as described
// in their docs
func FromJenkins() *ScmContext {
	if os.Getenv("JENKINS_URL") == "" {
		return nil
	}

	isPR := os.Getenv("CHANGE_ID") != ""  // only present on multibranch pipelines on Jenkins
	headRef := os.Getenv("BRANCH_NAME")   // only present on multibranch pipelines on Jenkins
	sha := os.Getenv("GIT_COMMIT")        // only present on multibranch pipelines on Jenkins
	baseRef := os.Getenv("CHANGE_TARGET") // only present on multibranch pipelines on Jenkins

	if isPR {
		return &ScmContext{
			ChangeRequest: isPR,
			Commit:        sha,
			Branch:        headRef,
			Provider:      "Jenkins",
			TargetBranch:  baseRef,
		}
	} else {
		return &ScmContext{
			ChangeRequest: isPR,
			Commit:        sha,
			Branch:        headRef,
			Provider:      "Jenkins",
			TargetBranch:  headRef,
		}
	}
}

Gitlab Runners

It reads the environment variables that are avaible in the context of a Gitlab runner execution:

// FromGitlab returns an SCM context for Gitlab, reading the right environment variables, as described
// in their docs
func FromGitlab() *ScmContext {
	if os.Getenv("CI_COMMIT_REF_NAME") == "" {
		return nil
	}

	sha := os.Getenv("CI_MERGE_REQUEST_SOURCE_BRANCH_SHA")      // only present on merge requests on Gitlab CI
	commitBranch := os.Getenv("CI_COMMIT_BRANCH")               // only present on branches on Gitlab CI
	headRef := os.Getenv("CI_COMMIT_REF_NAME")                  // only present on branches on Gitlab CI
	baseRef := os.Getenv("CI_MERGE_REQUEST_TARGET_BRANCH_NAME") // only present on merge requests on Gitlab CI

	isChangeRequest := (commitBranch == "")

	return &ScmContext{
		ChangeRequest: isChangeRequest,
		Commit:        sha,
		Branch:        headRef,
		Provider:      "Gitlab",
		TargetBranch:  baseRef,
	}
}

OpenTelemetry configuration

This tool is able to override the following attributes:

For using this tool in a distributed tracing scenario, where there is a parent trace in which the test reports traces should be attached, it's important to set the TRACEPARENT environment variable, so that the traces and spans generated by this tool are located under the right parent trace. Please read more on this here.

For further reference on environment variables in the OpenTelemetry SDK, please read the official specification

OpenTelemetry Attributes

This tool is going to parse the XML report produced by jUnit, or any other tool converting to that format, adding different attributes, separated by different categories:

• Test metrics attributes
• Ownership attributes

Metrics and Traces

The following attributes are added as metrics and/or traces.

Test execution attributes

For each test execution, represented by a test report file, the tool will add the following attributes to the metric document, including them in the trace representing the test execution.

Test case attributes

For each test case in the test execution, the tool will add the following attributes to the span document representing the test case:

Ownership attributes

These attributes are added to the traces and spans sent by the tool, identifying the owner (or owners) of the test suite, trying to correlate a test failure with an author or authors. To identify the owner, the tool will inspect the SCM repository for the project.

SCM attributes

Because the XML test report is evaluated for a project in a SCM repository, the tool will add the following attributes to each trace and span:

Change request attributes

The tool will add the following attributes to each trace and span if and only if the XML test report is evaluated in the context of a change requests for a Git repository:

A changeset is calculated based on the HEAD commit and the first ancestor between HEAD and the branch where the changeset is submitted against.

Docker image

It's possible to run the binary as a Docker image. To build and use the image

1. First build the Docker image using this Make goal:

make build-docker-image

1. Then start the Elastic Stack back-end:

make demo-start-elastic

1. Finally, once the services are started, run:

cat TEST-sample3.xml | docker run --rm -i --network elastic_junit2otlp --volume "$(pwd):/opt/projectname" --env OTEL_EXPORTER_OTLP_ENDPOINT=http://apm-server:8200 mdelapenya/junit2otlp:latest --service-name DOCKERFOO --trace-name TRACEBAR --repository-path "/opt/projectname"

• We are making the Docker container receive the pipe with the -i flag.
• We are attaching the container to the same Docker network where the services are running.
• We are passing an environment variable with the URL of the OpenTelemetry exporter endpoint, in this case an APM Server instance.
• We are passing command line flags to the container, setting the service name (DOCKERFOO) and the trace name (TRACEBAR).

Demos

To demonstrate how traces and metrics are sent to different back-ends, we are provising the following demos:

• Elastic
• Jaeger
• Prometheus
• Zipkin

Elastic

It will use the Elastic Stack as back-end, sending the traces, spans and metrics through the APM Server, storing them in Elasticsearch and finally using Kibana as visualisation layer.

make demo-start-elastic
go build && chmod +x ./junit2otlp
cat TEST-sample.xml | ./junit2otlp
cat TEST-sample2.xml | ./junit2otlp
cat TEST-sample3.xml | ./junit2otlp
open http://localhost:5601/app/apm/services?rangeFrom=now-15m&rangeTo=now&comparisonEnabled=true&comparisonType=day

Jaeger

It will use Jaeger as back-end, sending the traces, spans and metrics through the OpenTelemetry collector, storing them in memory.

make demo-start-jaeger
go build && chmod +x ./junit2otlp
cat TEST-sample.xml | ./junit2otlp
cat TEST-sample2.xml | ./junit2otlp
cat TEST-sample3.xml | ./junit2otlp
open http://localhost:16686

Prometheus

It will use Prometheus as back-end, sending the traces, spans and metrics through the OpenTelemetry collector, storing them in memory.

make demo-start-prometheus
go build && chmod +x ./junit2otlp
cat TEST-sample.xml | ./junit2otlp
cat TEST-sample2.xml | ./junit2otlp
cat TEST-sample3.xml | ./junit2otlp
open http://localhost:9090

Zipkin

It will use Prometheus as back-end, sending the traces, spans and metrics through the OpenTelemetry collector, storing them in memory.

make demo-start-zipkin
go build && chmod +x ./junit2otlp
cat TEST-sample.xml | ./junit2otlp
cat TEST-sample2.xml | ./junit2otlp
cat TEST-sample3.xml | ./junit2otlp
open http://localhost:9411