Capture stderr, too

app.py

@@ -17,6 +17,7 @@ app.config.from_object(config)
 
 class Authenticator(Resource):
     def post(self):
+        log.info("received login request %s", request.json)
         if request.json and request.json.get("token", None) == config.token:
             session["authorized"] = True
             log.info("session: %s", session)
@@ -39,60 +40,36 @@ class Starter(Resource):
         if "args" in request.json:
             args += request.json["args"]
         log.info("args: %s", args)
-        proc = subprocess.Popen(args, stdout=subprocess.PIPE, universal_newlines=True)
+        proc = subprocess.Popen(
-        procinfo = { "popen": proc, "pid": proc.pid, "started": time.time(), "stdout": [] }
+                            args,
+                            stdout=subprocess.PIPE, stderr=subprocess.PIPE,
+                            universal_newlines=True)
+        procinfo = { "popen": proc, "pid": proc.pid, "started": time.time(), "stdout": [], "stderr": [] }
         running.append(procinfo)
         pid = proc.pid
         log.info("pid: %s", pid)
         timeout = request.json.get("timeout", 0.0)
+        log.debug("timeout: %s", timeout)
         if timeout:
-            fd = proc.stdout
+            get_output(procinfo, timeout)
-            p = select.poll()
-            p.register(fd)
-            t0 = time.time()
-            t1 = t0 + timeout
-            while True:
-                dt = t1 - time.time()
-                if dt < 0:
-                    break
-                ready = p.poll(dt * 1000)
-                log.debug("ready: %s", ready)
-                if ready:
-                    ln = fd.readline()
-                    log.debug("ln: %s", ln)
-                    if ln == "":
-                        break;
-                    procinfo["stdout"].append(ln)
         try:
             procinfo["status"] = proc.wait(0.1)
             for ln in proc.stdout:
                 procinfo["stdout"].append(ln)
+            for ln in proc.stderr:
+                procinfo["stderr"].append(ln)
             procinfo["finished"] = time.time()
         except subprocess.TimeoutExpired:
             pass
         return { x: procinfo[x]
-                    for x in ["pid", "started", "stdout", "status", "finished"]
+                    for x in ["pid", "started", "stdout", "stderr", "status", "finished"]
                         if x in procinfo }
 
 class Status(Resource):
     def get(self, pid):
         for procinfo in running:
             if "finished" not in procinfo:
-                p = select.poll()
+                get_output(procinfo, 1.0)
-                p.register(procinfo["popen"].stdout)
-                t1 = time.time() + 1.0
-                while True:
-                    dt = t1 - time.time()
-                    if dt < 0:
-                        break
-                    ready = p.poll(dt * 1000)
-                    log.debug("ready: %s", ready)
-                    if ready:
-                        ln = procinfo["popen"].stdout.readline()
-                        log.debug("ln: %s", ln)
-                        if ln == "":
-                            break;
-                        procinfo["stdout"].append(ln)
                 try:
                     procinfo["status"] = procinfo["popen"].wait(0.1)
                     procinfo["finished"] = time.time()
@@ -101,10 +78,39 @@ class Status(Resource):
         for procinfo in running:
             if procinfo["pid"] == pid:
                 return { x: procinfo[x]
-                            for x in ["pid", "started", "stdout", "status", "finished"]
+                            for x in ["pid", "started", "stdout", "stderr", "status", "finished"]
                                 if x in procinfo }
 
+def get_output(procinfo, timeout):
+    proc = procinfo["popen"]
+    p = select.poll()
+    p.register(proc.stdout)
+    p.register(proc.stderr)
+    t0 = time.time()
+    t1 = t0 + timeout
+    eof = False
+    while not eof:
+        dt = t1 - time.time()
+        if dt < 0:
+            break
+        ready = p.poll(dt * 1000)
+        log.debug("ready: %s", ready)
+        for fd in ready:
 
+            if fd[0] == proc.stdout.fileno():
+                ln = proc.stdout.readline()
+                log.debug("ln: %s", ln)
+                if ln == "":
+                    eof = True
+                    continue
+                procinfo["stdout"].append(ln)
+            if fd[0] == proc.stderr.fileno():
+                ln = proc.stderr.readline()
+                log.debug("ln: %s", ln)
+                if ln == "":
+                    eof = True
+                    continue
+                procinfo["stderr"].append(ln)