49 lines
1.7 KiB
Go
49 lines
1.7 KiB
Go
package observability
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import (
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"context"
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"io"
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"net/http"
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"net/http/httptest"
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"strings"
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"testing"
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"time"
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)
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func TestMetricsHandlerRendersPrometheusFamilies(t *testing.T) {
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metrics := NewMetrics()
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metrics.ObserveHTTPRequest(http.MethodGet, "/anime/:id", http.StatusOK, 125*time.Millisecond)
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metrics.ObserveJikanRequest("/anime/{id}", http.StatusTooManyRequests, 800*time.Millisecond, assertErr{})
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metrics.ObserveWorkerTick("episodes_availability", nil)
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metrics.ObserveCache("jikan", "hit")
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metrics.ObserveCache("episode_availability", "miss")
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req := httptest.NewRequestWithContext(context.Background(), http.MethodGet, "/metrics", nil)
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rec := httptest.NewRecorder()
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metrics.Handler().ServeHTTP(rec, req)
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body, err := io.ReadAll(rec.Result().Body)
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if err != nil {
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t.Fatalf("read body: %v", err)
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}
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text := string(body)
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assertContains(t, text, `mal_http_requests_total{method="GET",route="/anime/:id",status="200"} 1`)
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assertContains(t, text, `mal_http_request_duration_seconds_count{method="GET",route="/anime/:id",status="200"} 1`)
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assertContains(t, text, `mal_jikan_upstream_requests_total{endpoint="/anime/{id}",status="429"} 1`)
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assertContains(t, text, `mal_jikan_upstream_errors_total{endpoint="/anime/{id}",status="429"} 1`)
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assertContains(t, text, `mal_worker_ticks_total{result="success",worker="episodes_availability"} 1`)
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assertContains(t, text, `mal_cache_operations_total{cache="episode_availability",result="miss"} 1`)
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}
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type assertErr struct{}
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func (assertErr) Error() string { return "boom" }
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func assertContains(t *testing.T, text string, want string) {
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t.Helper()
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if !strings.Contains(text, want) {
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t.Fatalf("missing metric line %q in:\n%s", want, text)
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}
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}
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