Merge pull request #349 from NebulousLabs/fix-err-msg

Use a clearer log message and add some debug output.

setup-scripts/log-checker.py

@@ -57,7 +57,9 @@ async def check_docker_logs():
         container_name = sys.argv[2]
 
     # Get the container id for siad.
-    stream = os.popen('docker ps -q --filter name=^{}$'.format(container_name))
+    cmd = 'docker ps -q --filter name=^{}$'.format(container_name)
+    print("[DEBUG] will run `{}`".format(cmd))
+    stream = os.popen(cmd)
     image_id = stream.read().strip()
 
     # Get the number of hours to look back in the logs or use 1 as default.
@@ -70,11 +72,25 @@ async def check_docker_logs():
     time_string = "{}h".format(check_hours)
 
     # Read the logs.
+    print("[DEBUG] Will run `docker logs --since {} {}`".format(time_string, image_id))
     proc = Popen(["docker", "logs", "--since", time_string, image_id], stdin=PIPE, stdout=PIPE, stderr=PIPE, text=True)
     std_out, std_err = proc.communicate()
 
     if len(std_err) > 0:
-        await send_msg(client, "Error reading docker logs output: {}".format(std_err), force_notify=True)
+        # Trim the error log to under 1MB.
+        one_mb = 1024*1024
+        if len(std_err) > one_mb:
+            pos = std_err.find("\n", -one_mb)
+            std_err = std_err[pos+1:]
+        upload_name = "{}-{}-{}-{}-{}:{}:{}_err.log".format(container_name, time.year, time.month, time.day, time.hour, time.minute, time.second)
+        await send_msg(client, "Error(s) found in log!", file=discord.File(io.BytesIO(std_err.encode()), filename=upload_name), force_notify=True)
+        # Send at most 1900 characters of logs, rounded down to the nearest new line.
+        # This is a limitation in the size of Discord messages - they can be at most
+        # 2000 characters long (and we send some extra characters before the error log).
+        if len(std_err) > 1900:
+            pos = std_err.find("\n", -1900)
+            std_err = std_err[pos+1:]
+        await send_msg(client, "Error(s) preview:\n{}".format(std_err), force_notify=True)
         return
 
     # If there are any critical errors. upload the whole log file.