open-nomad/command/agent/metrics_endpoint_test.go

package agent

import (
	"net/http"
	"net/http/httptest"
	"testing"

	metrics "github.com/armon/go-metrics"
	"github.com/hashicorp/nomad/testutil"
	"github.com/stretchr/testify/assert"
)

func TestHTTP_MetricsWithIllegalMethod(t *testing.T) {
	assert := assert.New(t)

	t.Parallel()
	httpTest(t, nil, func(s *TestAgent) {
		req, err := http.NewRequest("DELETE", "/v1/metrics", nil)
		assert.Nil(err)
		respW := httptest.NewRecorder()

		_, err = s.Server.MetricsRequest(respW, req)
		assert.NotNil(err, "HTTP DELETE should not be accepted for this endpoint")
	})
}

func TestHTTP_Metrics(t *testing.T) {
	assert := assert.New(t)

	t.Parallel()
	httpTest(t, nil, func(s *TestAgent) {
		// make a separate HTTP request first, to ensure Nomad has written metrics
		// and prevent a race condition
		req, err := http.NewRequest("GET", "/v1/agent/self", nil)
		assert.Nil(err)
		respW := httptest.NewRecorder()
		s.Server.AgentSelfRequest(respW, req)

		// now make a metrics endpoint request, which should be already initialized
		// and written to
		req, err = http.NewRequest("GET", "/v1/metrics", nil)
		assert.Nil(err)
		respW = httptest.NewRecorder()

		testutil.WaitForResult(func() (bool, error) {
			resp, err := s.Server.MetricsRequest(respW, req)
			if err != nil {
				return false, err
			}
			respW.Flush()

			res := resp.(metrics.MetricsSummary)
			return len(res.Gauges) != 0, nil
		}, func(err error) {
			t.Fatalf("should have metrics: %v", err)
		})
	})
}