add prebuild metrics and observability

enterprise/coderd/prebuilds/metricscollector.go

@@ -0,0 +1,71 @@
+package prebuilds
+
+import (
+	"context"
+	"time"
+
+	"cdr.dev/slog"
+
+	"github.com/prometheus/client_golang/prometheus"
+
+	"github.com/coder/coder/v2/coderd/database"
+	"github.com/coder/coder/v2/coderd/database/dbauthz"
+)
+
+var (
+	CreatedPrebuildsDesc   = prometheus.NewDesc("coderd_prebuilds_created", "The number of prebuilds created.", []string{"template_name", "preset_name"}, nil)
+	FailedPrebuildsDesc    = prometheus.NewDesc("coderd_prebuilds_failed", "The number of prebuilds that failed.", []string{"template_name", "preset_name"}, nil)
+	AssignedPrebuildsDesc  = prometheus.NewDesc("coderd_prebuilds_assigned", "The number of prebuilds that were assigned to a runner.", []string{"template_name", "preset_name"}, nil)
+	UsedPresetsDesc        = prometheus.NewDesc("coderd_presets_used", "The number of times a preset was used.", []string{"template_name", "preset_name"}, nil)
+	ExhaustedPrebuildsDesc = prometheus.NewDesc("coderd_prebuilds_exhausted", "The number of prebuilds that were exhausted.", []string{"template_name", "preset_name"}, nil)
+	DesiredPrebuildsDesc   = prometheus.NewDesc("coderd_prebuilds_desired", "The number of desired prebuilds.", []string{"template_name", "preset_name"}, nil)
+	ActualPrebuildsDesc    = prometheus.NewDesc("coderd_prebuilds_actual", "The number of actual prebuilds.", []string{"template_name", "preset_name"}, nil)
+	EligiblePrebuildsDesc  = prometheus.NewDesc("coderd_prebuilds_eligible", "The number of eligible prebuilds.", []string{"template_name", "preset_name"}, nil)
+)
+
+type MetricsCollector struct {
+	database database.Store
+	logger   slog.Logger
+}
+
+var _ prometheus.Collector = new(MetricsCollector)
+
+func NewMetricsCollector(db database.Store, logger slog.Logger) *MetricsCollector {
+	return &MetricsCollector{
+		database: db,
+		logger:   logger.Named("prebuilds_metrics_collector"),
+	}
+}
+
+func (*MetricsCollector) Describe(descCh chan<- *prometheus.Desc) {
+	descCh <- CreatedPrebuildsDesc
+	descCh <- FailedPrebuildsDesc
+	descCh <- AssignedPrebuildsDesc
+	descCh <- UsedPresetsDesc
+	descCh <- ExhaustedPrebuildsDesc
+	descCh <- DesiredPrebuildsDesc
+	descCh <- ActualPrebuildsDesc
+	descCh <- EligiblePrebuildsDesc
+}
+
+func (mc *MetricsCollector) Collect(metricsCh chan<- prometheus.Metric) {
+	// TODO (sasswart): get a proper actor in here, to deescalate from system
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+	// nolint:gocritic // just until we get back to this
+	metrics, err := mc.database.GetPrebuildMetrics(dbauthz.AsSystemRestricted(ctx))
+	if err != nil {
+		mc.logger.Error(ctx, "failed to get prebuild metrics", slog.Error(err))
+		return
+	}
+
+	for _, metric := range metrics {
+		metricsCh <- prometheus.MustNewConstMetric(CreatedPrebuildsDesc, prometheus.CounterValue, float64(metric.Created), metric.TemplateName.String, metric.PresetName.String)
+		metricsCh <- prometheus.MustNewConstMetric(FailedPrebuildsDesc, prometheus.CounterValue, float64(metric.Failed), metric.TemplateName.String, metric.PresetName.String)
+		metricsCh <- prometheus.MustNewConstMetric(AssignedPrebuildsDesc, prometheus.CounterValue, float64(metric.Assigned), metric.TemplateName.String, metric.PresetName.String)
+		metricsCh <- prometheus.MustNewConstMetric(ExhaustedPrebuildsDesc, prometheus.CounterValue, float64(metric.Exhausted), metric.TemplateName.String, metric.PresetName.String)
+		metricsCh <- prometheus.MustNewConstMetric(UsedPresetsDesc, prometheus.CounterValue, float64(metric.UsedPreset), metric.TemplateName.String, metric.PresetName.String)
+	}
+
+	// TODO (sasswart): read gauges from controller
+}

enterprise/coderd/prebuilds/metricscollector_test.go

@@ -0,0 +1,69 @@
+package prebuilds_test
+
+import (
+	"context"
+	"database/sql"
+	"testing"
+	"time"
+
+	"github.com/google/uuid"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/stretchr/testify/require"
+
+	"cdr.dev/slog/sloggers/slogtest"
+	"github.com/coder/coder/v2/coderd/database"
+	"github.com/coder/coder/v2/coderd/database/dbgen"
+	"github.com/coder/coder/v2/coderd/database/dbtestutil"
+	"github.com/coder/coder/v2/enterprise/coderd/prebuilds"
+)
+
+func TestMetricsCollector(t *testing.T) {
+	t.Parallel()
+
+	db, _ := dbtestutil.NewDB(t, dbtestutil.WithDumpOnFailure())
+
+	org := dbgen.Organization(t, db, database.Organization{})
+	user := dbgen.User(t, db, database.User{})
+	template := dbgen.Template(t, db, database.Template{
+		CreatedBy:      user.ID,
+		OrganizationID: org.ID,
+	})
+	templateVersion := dbgen.TemplateVersion(t, db, database.TemplateVersion{
+		TemplateID:     uuid.NullUUID{UUID: template.ID, Valid: true},
+		OrganizationID: org.ID,
+		CreatedBy:      user.ID,
+	})
+
+	logger := slogtest.Make(t, &slogtest.Options{IgnoreErrors: true})
+	collector := prebuilds.NewMetricsCollector(db, logger)
+
+	registry := prometheus.NewRegistry()
+	registry.Register(collector)
+
+	preset, err := db.InsertPreset(context.Background(), database.InsertPresetParams{
+		TemplateVersionID: templateVersion.ID,
+		Name:              "test",
+	})
+	require.NoError(t, err)
+	workspace := dbgen.Workspace(t, db, database.WorkspaceTable{
+		OrganizationID: org.ID,
+		OwnerID:        user.ID,
+		TemplateID:     template.ID,
+	})
+	job := dbgen.ProvisionerJob(t, db, nil, database.ProvisionerJob{
+		OrganizationID: org.ID,
+		CompletedAt:    sql.NullTime{Time: time.Now(), Valid: true},
+		InitiatorID:    prebuilds.OwnerID,
+	})
+	dbgen.WorkspaceBuild(t, db, database.WorkspaceBuild{
+		WorkspaceID:             workspace.ID,
+		TemplateVersionID:       templateVersion.ID,
+		TemplateVersionPresetID: uuid.NullUUID{UUID: preset.ID, Valid: true},
+		InitiatorID:             prebuilds.OwnerID,
+		JobID:                   job.ID,
+	})
+
+	metrics, err := registry.Gather()
+	require.NoError(t, err)
+	require.Equal(t, 5, len(metrics))
+}