Error handling in subprocess run (#516)

src/web/pi_cmds.py

@@ -44,6 +44,7 @@ def running_env():
     git contains the git hash of the checked out code
     env is the various system information where this app is running
     """
+    try:
         ra_git_version = (
             subprocess.run(
                 ["git", "rev-parse", "HEAD"],
@@ -53,6 +54,12 @@ def running_env():
             .stdout.decode("utf-8")
             .strip()
         )
+    except subprocess.CalledProcessError as error:
+        logging.warning("Executed shell command: %s", " ".join(error.cmd))
+        logging.warning("Got error: %s", error.stderr.decode("utf-8"))
+        ra_git_version = ""
+
+    try:
         pi_version = (
             subprocess.run(
                 ["uname", "-a"],
@@ -62,6 +69,11 @@ def running_env():
             .stdout.decode("utf-8")
             .strip()
         )
+    except subprocess.CalledProcessError as error:
+        logging.warning("Executed shell command: %s", " ".join(error.cmd))
+        logging.warning("Got error: %s", error.stderr.decode("utf-8"))
+        pi_version = "Unknown"
+
     return {"git": ra_git_version, "env": pi_version}
 
 
@@ -70,28 +82,46 @@ def running_proc(daemon):
     Takes (str) daemon
     Returns (int) proc, which is the number of processes currently running
     """
-    process = subprocess.run(
+    try:
+        processes = (
+            subprocess.run(
                 ["ps", "aux"],
                 capture_output=True,
                 check=True,
                 )
-    output = process.stdout.decode("utf-8")
+            .stdout.decode("utf-8")
+            .strip()
+        )
+    except subprocess.CalledProcessError as error:
+        logging.warning("Executed shell command: %s", " ".join(error.cmd))
+        logging.warning("Got error: %s", error.stderr.decode("utf-8"))
+        processes = ""
+
     from re import findall
-    proc = findall(daemon, output)
-    return len(proc)
+    matching_processes = findall(daemon, processes)
+    return len(matching_processes)
 
 
 def is_bridge_setup():
     """
     Returns (bool) True if the rascsi_bridge network interface exists
     """
-    process = subprocess.run(
+    try:
+        bridges = (
+            subprocess.run(
                 ["brctl", "show"],
                 capture_output=True,
                 check=True,
                 )
-    output = process.stdout.decode("utf-8")
-    if "rascsi_bridge" in output:
+            .stdout.decode("utf-8")
+            .strip()
+        )
+    except subprocess.CalledProcessError as error:
+        logging.warning("Executed shell command: %s", " ".join(error.cmd))
+        logging.warning("Got error: %s", error.stderr.decode("utf-8"))
+        bridges = ""
+
+    if "rascsi_bridge" in bridges:
         return True
     return False