From ec6645b832a7627e41ca451d0d30bf321f07fd54 Mon Sep 17 00:00:00 2001
From: Aaron Lehmann <alehmann@netflix.com>
Date: Mon, 13 Jan 2025 16:30:02 -0800
Subject: [PATCH] chore: add parent PID to coder ssh log file name (#16080)

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.

See also #16078.
---
 cli/ssh.go | 30 +++++++++++++++++++-----------
 1 file changed, 19 insertions(+), 11 deletions(-)

diff --git a/cli/ssh.go b/cli/ssh.go
index ea03916e3c..4fa836e44e 100644
--- a/cli/ssh.go
+++ b/cli/ssh.go
@@ -131,18 +131,26 @@ 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,