Merge pull request #1929 from onflow/mfbz/emulator-middleware

Added metrics middleware to emulator start

Author: mfbz

.goreleaser.yaml

@@ -55,4 +55,4 @@ release:
     owner: onflow
     name: flow-cli
   prerelease: auto
-  draft: false
+  draft: false

go.mod

@@ -21,7 +21,7 @@ require (
 	github.com/onflow/fcl-dev-wallet v0.8.0
 	github.com/onflow/flixkit-go/v2 v2.3.0
 	github.com/onflow/flow-core-contracts/lib/go/templates v1.6.1
-	github.com/onflow/flow-emulator v1.3.0
+	github.com/onflow/flow-emulator v1.4.0
 	github.com/onflow/flow-evm-gateway v1.0.3
 	github.com/onflow/flow-go v0.38.1-0.20250218174738-2181389f9f7d
 	github.com/onflow/flow-go-sdk v1.4.0

go.sum

@@ -844,8 +844,8 @@ github.com/onflow/flow-core-contracts/lib/go/contracts v1.5.1-preview h1:W+QkNQc
 github.com/onflow/flow-core-contracts/lib/go/contracts v1.5.1-preview/go.mod h1:LyCICUK6sK1jtEyb+3GuRw5tYfHT1uxACLwLTLxw/0I=
 github.com/onflow/flow-core-contracts/lib/go/templates v1.6.1 h1:Y0bDvS5fTOCrKr7QFl0by3qTq7MFnauVnHoxwW6nQzo=
 github.com/onflow/flow-core-contracts/lib/go/templates v1.6.1/go.mod h1:pN768Al/wLRlf3bwugv9TyxniqJxMu4sxnX9eQJam64=
-github.com/onflow/flow-emulator v1.3.0 h1:SqKbXZ79GcfnDDaggQccEkp6fBMFQVG4AxRtpT+jYYk=
-github.com/onflow/flow-emulator v1.3.0/go.mod h1:+RV5j5TYEE0VYtUAEn/vduecy8yK8P+rB+a9BCc3gQA=
+github.com/onflow/flow-emulator v1.4.0 h1:LSNYV4Dd6Aetd2Q/4qc1mes5BIt4JTKMoQfr5QXdBFQ=
+github.com/onflow/flow-emulator v1.4.0/go.mod h1:+RV5j5TYEE0VYtUAEn/vduecy8yK8P+rB+a9BCc3gQA=
 github.com/onflow/flow-evm-gateway v1.0.3 h1:Mlz3EBVTz7wpUwrDTVSJtd8CG/DtEe920UDUPiTGN7Y=
 github.com/onflow/flow-evm-gateway v1.0.3/go.mod h1:JukrDrisLQvup7FwCkA/z7LEKtLpCETPSu25CAuuEN0=
 github.com/onflow/flow-ft/lib/go/contracts v1.0.1 h1:Ts5ob+CoCY2EjEd0W6vdLJ7hLL3SsEftzXG2JlmSe24=

internal/command/command.go

@@ -364,14 +364,14 @@ func initCrashReporting() {
 }
 
 // The token is injected at build-time using ldflags
-var mixpanelToken = ""
+var MixpanelToken = ""
 
 func UsageMetrics(command *cobra.Command, wg *sync.WaitGroup) {
-	if !settings.MetricsEnabled() || mixpanelToken == "" {
+	if !settings.MetricsEnabled() || MixpanelToken == "" {
 		return
 	}
 	wg.Add(1)
-	client := mixpanel.New(mixpanelToken, "")
+	client := mixpanel.New(MixpanelToken, "")
 
 	// calculates a user ID that doesn't leak any personal information
 	usr, _ := user.Current() // ignore err, just use empty string

internal/emulator/start.go

@@ -19,11 +19,17 @@
 package emulator
 
 import (
+	"crypto/sha256"
+	"encoding/base64"
 	"errors"
 	"fmt"
+	"net/http"
 	"os"
+	"os/user"
+	"runtime"
 	"sync"
 
+	"github.com/dukex/mixpanel"
 	"github.com/onflow/flow-emulator/cmd/emulator/start"
 	"github.com/onflow/flow-go-sdk/crypto"
 	"github.com/spf13/afero"
@@ -32,12 +38,17 @@ import (
 	"github.com/onflow/flowkit/v2"
 	"github.com/onflow/flowkit/v2/config"
 
+	"github.com/onflow/flow-cli/build"
 	"github.com/onflow/flow-cli/internal/command"
+	"github.com/onflow/flow-cli/internal/settings"
 	"github.com/onflow/flow-cli/internal/util"
 )
 
 var Cmd *cobra.Command
 
+// Mixpanel client to be reused on each http request of the middleware
+var mixpanelClient mixpanel.Mixpanel
+
 func configuredServiceKey(
 	init bool,
 	_ crypto.SignatureAlgorithm,
@@ -97,8 +108,45 @@ func configuredServiceKey(
 	return *privateKey, serviceAccount.Key.SigAlgo(), serviceAccount.Key.HashAlgo()
 }
 
+func trackRequestMiddleware(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		// Generate a unique user ID
+		usr, _ := user.Current() // ignore err, just use empty string
+		hash := sha256.Sum256([]byte(fmt.Sprintf("%s%s", usr.Username, usr.Uid)))
+		userID := base64.StdEncoding.EncodeToString(hash[:])
+
+		// Track the request in Mixpanel
+		_ = mixpanelClient.Track(userID, "emulator-request", &mixpanel.Event{
+			IP: "0", // do not track IPs
+			Properties: map[string]any{
+				"method":  r.Method,
+				"url":     r.URL.String(),
+				"version": build.Semver(),
+				"os":      runtime.GOOS,
+				"ci":      os.Getenv("CI") != "", // CI is commonly set by CI providers
+			},
+		})
+
+		// Call the next handler
+		next.ServeHTTP(w, r)
+	})
+}
+
 func init() {
-	Cmd = start.Cmd(configuredServiceKey)
+	// Initialize mixpanel client only if metrics are enabled and token is not empty
+	if settings.MetricsEnabled() && command.MixpanelToken != "" {
+		mixpanelClient = mixpanel.New(command.MixpanelToken, "")
+		Cmd = start.Cmd(start.StartConfig{
+			GetServiceKey:   configuredServiceKey,
+			RestMiddlewares: []start.HttpMiddleware{trackRequestMiddleware},
+		})
+	} else {
+		Cmd = start.Cmd(start.StartConfig{
+			GetServiceKey:   configuredServiceKey,
+			RestMiddlewares: []start.HttpMiddleware{},
+		})
+	}
+
 	Cmd.Use = "emulator"
 	Cmd.Short = "Run Flow network for development"
 	Cmd.GroupID = "tools"