159 lines
2.8 KiB
Text
159 lines
2.8 KiB
Text
# Observability
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Короткий Фёдор
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## Prometheus Data Model
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* Data Model
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```
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http_requests_total
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<metric name>{<label name>=<label value>, ...}
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api_http_requests_total{method="POST", handler="/messages"}
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```
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* Metric Types
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* Counter
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- `network_received_bytes`
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- `requests_total`
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* Gauge
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- `go_heap_bytes`
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* Histogram
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- `request_duration`
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## Prometheus architecture
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.image prometheus.png _ 800
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## Prometheus query language
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* Selectors
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```
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http_requests_total
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http_requests_total{job="prometheus",group="canary"}
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http_requests_total{environment=~"staging|testing|development",method!="GET"}
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```
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* Ranges
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```
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http_requests_total{job="prometheus"}[5m]
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```
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* Functions
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```
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rate(http_requests_total[5m])
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```
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* Agregation
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```
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sum by (job) (rate(http_requests_total[5m]))
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sum by (app, proc) (
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instance_memory_limit_bytes - instance_memory_usage_bytes
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) / 1024 / 1024
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topk(3, sum by (app, proc) (rate(instance_cpu_time_ns[5m])))
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```
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## Prometheus API examples
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```go
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package main
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import (
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"net/http"
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"github.com/prometheus/client_golang/prometheus/promhttp"
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)
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func main() {
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http.Handle("/metrics", promhttp.Handler())
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http.ListenAndServe(":2112", nil)
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}
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```
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## Prometheus API examples
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```go
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func recordMetrics() {
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go func() {
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for {
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opsProcessed.Inc()
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time.Sleep(2 * time.Second)
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}
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}()
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}
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var (
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opsProcessed = promauto.NewCounter(prometheus.CounterOpts{
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Name: "myapp_processed_ops_total",
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Help: "The total number of processed events",
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})
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)
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```
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## Prometheus API examples
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```go
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var (
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requestCount = promauto.With(reg).NewCounterVec(
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prometheus.CounterOpts{
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Name: "http_requests_total",
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Help: "Total number of HTTP requests by status code and method.",
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},
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[]string{"code", "method"},
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)
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)
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func countRequest(code, method string) {
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requestCount.WithLavelValues(code, method).Inc()
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}
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```
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## Example: Request Handlers
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Что измерять?
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## Example: Job Queue
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Что измерять?
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## Example: Database Pool
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Что измерять?
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## OpenTelemetry data model
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.image trace.png _ 700
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## Jaeger architecture
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.image jaeger.png _ 800
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## trace API examples
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```
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var (
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tracer = otel.Tracer("rolldice")
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)
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func rolldice(w http.ResponseWriter, r *http.Request) {
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ctx, span := tracer.Start(r.Context(), "roll")
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defer span.End()
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roll := 1 + rand.Intn(6)
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span.SetAttributes(attribute.Int("roll.value", roll))
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resp := strconv.Itoa(roll) + "\n"
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if _, err := io.WriteString(w, resp); err != nil {
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span.RecordError(err)
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}
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}
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```
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## HTTP Propagation
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```
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> GET / HTTP/1.1
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> Host: localhost:3001
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> Accept: */*
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> traceparent: 00-d4cda95b652f4a1592b449d5929fda1b-6e0c63257de34c92-01
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```
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