[Profiler] Use Exec to avoid templating issues. (ray-project#39019)

Cleans up profiler to always use the actual `py-spy` path. This PR also uses a list of arguments to pass to subprocess, instead of a string. Finally, this PR ensures that format is one of the expected types.

dashboard/modules/reporter/profile_manager.py

@@ -1,4 +1,5 @@
 import asyncio
+import shutil
 import subprocess
 import sys
 from pathlib import Path
@@ -49,11 +50,12 @@ def _format_failed_pyspy_command(cmd, stdout, stderr) -> str:
 # If we can sudo, always try that. Otherwise, py-spy will only work if the user has
 # root privileges or has configured setuid on the py-spy script.
 async def _can_passwordless_sudo() -> bool:
-    process = await asyncio.create_subprocess_shell(
-        "sudo -n true",
+    process = await asyncio.create_subprocess_exec(
+        "sudo",
+        "-n",
+        "true",
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
-        shell=True,
     )
     _, _ = await process.communicate()
     return process.returncode == 0
@@ -65,17 +67,20 @@ def __init__(self, profile_dir_path: str):
         self.profile_dir_path.mkdir(exist_ok=True)
 
     async def trace_dump(self, pid: int, native: bool = False) -> (bool, str):
-        cmd = f"py-spy dump -p {pid}"
+        pyspy = shutil.which("py-spy")
+        if pyspy is None:
+            return False, "py-spy is not installed"
+
+        cmd = [pyspy, "dump", "-p", str(pid)]
         # We
         if sys.platform == "linux" and native:
-            cmd += " --native"
+            cmd.append("--native")
         if await _can_passwordless_sudo():
-            cmd = "sudo -n " + cmd.replace("py-spy", "$(which py-spy)")
-        process = await asyncio.create_subprocess_shell(
-            cmd,
+            cmd = ["sudo", "-n"] + cmd
+        process = await asyncio.create_subprocess_exec(
+            *cmd,
             stdout=subprocess.PIPE,
             stderr=subprocess.PIPE,
-            shell=True,
         )
         stdout, stderr = await process.communicate()
         if process.returncode != 0:
@@ -86,26 +91,43 @@ async def trace_dump(self, pid: int, native: bool = False) -> (bool, str):
     async def cpu_profile(
         self, pid: int, format="flamegraph", duration: float = 5, native: bool = False
     ) -> (bool, str):
+        pyspy = shutil.which("py-spy")
+        if pyspy is None:
+            return False, "py-spy is not installed"
+
+        if format not in ("flamegraph", "raw", "speedscope"):
+            return (
+                False,
+                f"Invalid format {format}, " + "must be [flamegraph, raw, speedscope]",
+            )
+
         if format == "flamegraph":
             extension = "svg"
         else:
             extension = "txt"
         profile_file_path = (
             self.profile_dir_path / f"{format}_{pid}_cpu_profiling.{extension}"
         )
-        cmd = (
-            f"py-spy record "
-            f"-o {profile_file_path} -p {pid} -d {duration} -f {format}"
-        )
+        cmd = [
+            pyspy,
+            "record",
+            "-o",
+            profile_file_path,
+            "-p",
+            str(pid),
+            "-d",
+            str(duration),
+            "-f",
+            format,
+        ]
         if sys.platform == "linux" and native:
-            cmd += " --native"
+            cmd.append("--native")
         if await _can_passwordless_sudo():
-            cmd = "sudo -n " + cmd.replace("py-spy", "$(which py-spy)")
-        process = await asyncio.create_subprocess_shell(
-            cmd,
+            cmd = ["sudo", "-n"] + cmd
+        process = await asyncio.create_subprocess_exec(
+            *cmd,
             stdout=subprocess.PIPE,
             stderr=subprocess.PIPE,
-            shell=True,
         )
         stdout, stderr = await process.communicate()
         if process.returncode != 0: