chore: add parent PID to coder ssh log file name

aaronlehmann · aaronlehmann · commit 52ab6f61e74e · 2025-01-08T20:50:27.000-08:00
Part of bringing coder ssh to parity with coder vscodessh is associating
the log files with a particular parent process (in this case, the ssh
process that spawned the coder CLI via ProxyCommand). coder vscodessh
named log files using the parent PID, but coder ssh is missing this. Add
the parent PID to the log file name when used in stdio mode so that
the VS Code extension will be able to identify the correct log file.
diff --git a/cli/ssh.go b/cli/ssh.go
@@ -124,18 +124,26 @@ func (r *RootCmd) ssh() *serpent.Command {
 				if err != nil {
 					return xerrors.Errorf("generate nonce: %w", err)
 				}
-				logFilePath := filepath.Join(
-					logDirPath,
-					fmt.Sprintf(
-						"coder-ssh-%s-%s.log",
-						// The time portion makes it easier to find the right
-						// log file.
-						time.Now().Format("20060102-150405"),
-						// The nonce prevents collisions, as SSH invocations
-						// frequently happen in parallel.
-						nonce,
-					),
+				logFileBaseName := fmt.Sprintf(
+					"coder-ssh-%s-%s",
+					// The time portion makes it easier to find the right
+					// log file.
+					time.Now().Format("20060102-150405"),
+					// The nonce prevents collisions, as SSH invocations
+					// frequently happen in parallel.
+					nonce,
 				)
+				if stdio {
+					// The VS Code extension obtains the PID of the SSH process to
+					// find the log file associated with a SSH session.
+					//
+					// We get the parent PID because it's assumed `ssh` is calling this
+					// command via the ProxyCommand SSH option.
+					logFileBaseName += fmt.Sprintf("-%d", os.Getppid())
+				}
+				logFileBaseName += ".log"
+
+				logFilePath := filepath.Join(logDirPath, logFileBaseName)
 				logFile, err := os.OpenFile(
 					logFilePath,
 					os.O_CREATE|os.O_APPEND|os.O_WRONLY|os.O_EXCL,
