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Set up Go profiling in pull mode

In pull mode, the Grafana Agent periodically retrieves profiles from Golang applications, specifically targeting the /debug/pprof/* endpoints.

To set up Golang profiling in pull mode, you need to:

  1. Expose pprof endpoints
  2. Install Grafana Agent
  3. Prepare Grafana Agent configuration file
  4. Start Grafana Agent

Expose pprof endpoints

Ensure your Golang application exposes pprof endpoints.

  1. Get godeltaprof package

    bash
    go get github.com/grafana/pyroscope-go/godeltaprof@latest
  2. Import net/http/pprof and godeltaprof/http/pprof packages at the start of your application.

    Go
    import _ "net/http/pprof"
    import _ "github.com/grafana/pyroscope-go/godeltaprof/http/pprof"

Install Grafana Agent

This procedure uses Grafana Agent to send data to Pyroscope using an example River configuration file for the Grafana Agent in Flow mode. Make sure you have Grafana Agent in Flow mode installed.

Prepare Grafana Agent Flow configuration file

In the Grafana Agent Flow configuration file, you need to add at least two blocks: pyroscope.write and pyroscope.scrape.

  1. Add pyroscope.write block.

    river
    pyroscope.write "write_job_name" {
            endpoint {
                    url = "http://localhost:4040"
            }
    }
  2. Add pyroscope.scrape block.

    river
    pyroscope.scrape "scrape_job_name" {
            targets    = [{"__address__" = "localhost:4040", "service_name" = "example_service"}]
            forward_to = [pyroscope.write.write_job_name.receiver]
    
            profiling_config {
                    profile.process_cpu {
                            enabled = true
                    }
    
                    profile.godeltaprof_memory {
                            enabled = true
                    }
    
                    profile.memory { // disable memory, use godeltaprof_memory instead
                            enabled = false
                    }
    
                    profile.godeltaprof_mutex {
                            enabled = true
                    }
    
                    profile.mutex { // disable mutex, use godeltaprof_mutex instead
                            enabled = false
                    }
    
                    profile.godeltaprof_block {
                            enabled = true
                    }
    
                    profile.block { // disable block, use godeltaprof_block instead
                            enabled = false
                    }
    
                    profile.goroutine {
                            enabled = true
                    }
            }
    }
  3. Save the changes to the file.

Start Grafana Agent Flow

  1. Start a local Pyroscope instance for testing purposes
    bash
    docker run -p 4040:4040 grafana/pyroscope 
  2. Start Grafana Agent
    bash
    grafana-agent-flow run conifguration.river
  3. Open a browser to http://localhost:4040. The page should list profiles.

Examples

Send data to Grafana Cloud

Your Grafana Cloud URL, username, and password can be found on the “Details Page” for Pyroscope from your stack on grafana.com. On this same page, create a token and use it as the Basic authentication password.

river
pyroscope.write "write_job_name" {
        endpoint {
                url = "<Grafana Cloud URL>"

                basic_auth {
                        username = "<Grafana Cloud User>"
                        password = "<Grafana Cloud Password>"
                }
        }
        
}

Discover Kubernetes targets

  1. Select all pods
river
discovery.kubernetes "all_pods" {
        role = "pod"
}
  1. Drop not running pods, create namespace, pod, node and container labels. Compose service_name label based on namespace and container labels. Select only services matching regex pattern (ns1/.*)|(ns2/container-.*0).

    river
    
    discovery.relabel "specific_pods" {
            targets = discovery.kubernetes.all_pods.targets
    
            rule {
                    action        = "drop"
                    regex         = "Succeeded|Failed|Completed"
                    source_labels = ["__meta_kubernetes_pod_phase"]
            }
    
            rule {
                    action        = "replace"
                    source_labels = ["__meta_kubernetes_namespace"]
                    target_label  = "namespace"
            }
    
            rule {
                    action        = "replace"
                    source_labels = ["__meta_kubernetes_pod_name"]
                    target_label  = "pod"
            }
    
            rule {
                    action        = "replace"
                    source_labels = ["__meta_kubernetes_node_name"]
                    target_label  = "node"
            }
    
            rule {
                    action        = "replace"
                    source_labels = ["__meta_kubernetes_pod_container_name"]
                    target_label  = "container"
            }
    
            rule {
                    action        = "replace"
                    regex         = "(.*)@(.*)"
                    replacement   = "${1}/${2}"
                    separator     = "@"
                    source_labels = ["__meta_kubernetes_namespace", "__meta_kubernetes_pod_container_name"]
                    target_label  = "service_name"
            }
    
            rule { 
                    action        = "keep"
                    regex         = "(ns1/.*)|(ns2/container-.*0)"
                    source_labels = ["service_name"]
            }
    }
  2. Use discovery.relabel.specific_pods.targets as a target for pyroscope.scrape block.

    river
        pyroscope.scrape "scrape_job_name" {
                targets    = discovery.relabel.specific_pods.output
                ...
        }

Exposing pprof endpoints

If you don’t use http.DefaultServeMux, you can register /debug/pprof/* handlers to your own http.ServeMux

Go
var mux *http.ServeMux
mux.Handle("/debug/pprof/", http.DefaultServeMux)

Or, if you use gorilla/mux:

Go
var router *mux.Router
router.PathPrefix("/debug/pprof").Handler(http.DefaultServeMux)

References

Example using grafana-agent. pyroscope.scrape pyroscope.write discovery.kubernetes discovery.docker discovery.relabel