From de635ac0a88a3bec230564e258c65fa2cfd5284b Mon Sep 17 00:00:00 2001
From: Josh Bleecher Snyder <josh@tailscale.com>
Date: Fri, 3 Dec 2021 10:29:51 -0800
Subject: [PATCH] cmd/tailscale: print more detail in connection failure error
 message

Before:

failed to connect to local tailscaled (which appears to be running). Got error: Get "http://local-tailscaled.sock/localapi/v0/status": EOF

After:

failed to connect to local tailscaled (which appears to be running as IPNExtension, pid 2118). Got error: Get "http://local-tailscaled.sock/localapi/v0/status": EOF

This was useful just now, as it made it clear that tailscaled I thought
I was connecting to might not in fact be running; there was
a second tailscaled running that made the error message slightly misleading.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
---
 cmd/tailscale/cli/diag.go | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/cmd/tailscale/cli/diag.go b/cmd/tailscale/cli/diag.go
index 10b302c83..5a09b1714 100644
--- a/cmd/tailscale/cli/diag.go
+++ b/cmd/tailscale/cli/diag.go
@@ -25,23 +25,23 @@ func fixTailscaledConnectError(origErr error) error {
 	if err != nil {
 		return fmt.Errorf("failed to connect to local Tailscaled process and failed to enumerate processes while looking for it")
 	}
-	found := false
+	var foundProc ps.Process
 	for _, proc := range procs {
 		base := filepath.Base(proc.Executable())
 		if base == "tailscaled" {
-			found = true
+			foundProc = proc
 			break
 		}
 		if runtime.GOOS == "darwin" && base == "IPNExtension" {
-			found = true
+			foundProc = proc
 			break
 		}
 		if runtime.GOOS == "windows" && strings.EqualFold(base, "tailscaled.exe") {
-			found = true
+			foundProc = proc
 			break
 		}
 	}
-	if !found {
+	if foundProc == nil {
 		switch runtime.GOOS {
 		case "windows":
 			return fmt.Errorf("failed to connect to local tailscaled process; is the Tailscale service running?")
@@ -52,5 +52,5 @@ func fixTailscaledConnectError(origErr error) error {
 		}
 		return fmt.Errorf("failed to connect to local tailscaled process; it doesn't appear to be running")
 	}
-	return fmt.Errorf("failed to connect to local tailscaled (which appears to be running). Got error: %w", origErr)
+	return fmt.Errorf("failed to connect to local tailscaled (which appears to be running as %v, pid %v). Got error: %w", foundProc.Executable(), foundProc.Pid(), origErr)
 }