run go foo during the buiild

.github/workflows/test-ci-instrumentation-workflow.yml

@@ -0,0 +1,31 @@
+name: test-ci-instrumentation-workflow.yml
+on:
+  push:
+    branches:
+      - grambbledook/test-toolexec-instrumentation
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v5
+        with:
+          persist-credentials: false
+      - name: Setup Go
+        uses: actions/setup-go@v6.0.0
+        with:
+          go-version-file: go.mod
+          cache: true
+
+      - name: Build foo
+        run: |
+          cd ./goinst
+          GOWORK=off go build -o foo
+          mv ./foo ../foo
+          cd ../
+
+      - name: Build Grafana
+        run: |
+          make build-go
+

goinst/go.mod

@@ -0,0 +1,3 @@
+module goinst
+
+go 1.25.3

goinst/main.go

@@ -0,0 +1,38 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"time"
+)
+
+func main() {
+	if len(os.Args) < 2 {
+		fmt.Fprintln(os.Stderr, "Usage: toolexec <tool> [args...]")
+		os.Exit(1)
+	}
+
+	tool := os.Args[1]
+	args := os.Args[2:]
+
+	start := time.Now()
+
+	cmd := exec.Command(tool, args...)
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+
+	err := cmd.Run()
+	elapsed := time.Since(start)
+
+	fmt.Fprintf(os.Stderr, "tool=%s elapsed=%s\n", tool, elapsed)
+
+	if err != nil {
+		if exitErr, ok := err.(*exec.ExitError); ok {
+			os.Exit(exitErr.ExitCode())
+		} else {
+			fmt.Fprintln(os.Stderr, "Error:", err)
+			os.Exit(1)
+		}
+	}
+}

pkg/build/cmd.go

@@ -207,7 +207,7 @@ func doBuild(binaryName, pkg string, opts BuildOpts) error {
 	// We should not publish Grafana as a Go module, disabling vcs changes the version to (devel)
 	// and works better with SBOM and Vulnerability Scanners.
 	args = append(args, "-buildvcs=false")
-
+	args = append(args, "-toolexec=\"./foo\"")
 	args = append(args, "-o", binary)
 	args = append(args, pkg)