Merge lp:~townsend/libertine/verbose-lxc-errors into lp:libertine

[Christopher Townsend]

Be more verbose when the LXC container won't start.

[Libertine CI Bot (libertine-ci-bot)]

PASSED: Continuous integration, rev:241
https://jenkins.canonical.com/libertine/job/libertine-ci-verify-mp/257/
Executed test runs:
    SUCCESS: https://jenkins.canonical.com/libertine/job/generic-ci-generate-dsc/260
    SUCCESS: https://jenkins.canonical.com/libertine/job/libertine-ci-build-and-test-dsc/architecture=amd64,distribution=vivid,label_exp=jenkins-slave-0%20%7C%7C%20jenkins-slave-2/219
    SUCCESS: https://jenkins.canonical.com/libertine/job/libertine-ci-build-and-test-dsc/architecture=amd64,distribution=xenial,label_exp=jenkins-slave-0%20%7C%7C%20jenkins-slave-2/219
    SUCCESS: https://jenkins.canonical.com/libertine/job/libertine-ci-build-and-test-dsc/architecture=i386,distribution=vivid,label_exp=jenkins-slave-0%20%7C%7C%20jenkins-slave-2/219
    SUCCESS: https://jenkins.canonical.com/libertine/job/libertine-ci-build-and-test-dsc/architecture=i386,distribution=xenial,label_exp=jenkins-slave-0%20%7C%7C%20jenkins-slave-2/219
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review: Approve (continuous-integration)

[Larry Price (larryprice)]

Although the raw errors still aren't super helpful for regular users, this should do wonders for debugging.

lgtm

review: Approve

=== modified file 'python/libertine/LxcContainer.py'
--- python/libertine/LxcContainer.py	2016-05-20 14:37:56 +0000
+++ python/libertine/LxcContainer.py	2016-06-10 20:44:27 +0000
@@ -18,6 +18,8 @@
 import psutil
 import shlex
 import subprocess
+import tempfile
+
 from .Libertine import BaseContainer
 from . import utils
 from socket import *
@@ -82,6 +84,9 @@
         super().__init__(container_id)
         self.container_type = "lxc"
         self.container = lxc_container(container_id)
+        self.lxc_log_file = os.path.join(tempfile.mkdtemp(), 'lxc-start.log')
+        self.container.append_config_item("lxc.logfile", self.lxc_log_file)
+        self.container.append_config_item("lxc.logpriority", "3")
 
     def is_running(self):
         return self.container.running
@@ -100,8 +105,10 @@
     def start_container(self):
         if not self.container.running:
             if not self.container.start():
+                self._dump_lxc_log()
                 raise RuntimeError("Container failed to start")
             if not self.container.wait("RUNNING", 10):
+                self._dump_lxc_log()
                 raise RuntimeError("Container failed to enter the RUNNING state")
 
         if not self.container.get_ips(timeout=30):
@@ -298,3 +305,8 @@
         # Receive the reply from libertine-lxc-manager (ignore it for now).
         data = libertine_lxc_mgr_sock.recv(1024)
         libertine_lxc_mgr_sock.close()
+
+    def _dump_lxc_log(self):
+        with open(self.lxc_log_file, 'r') as fd:
+            for line in fd:
+                print(line.lstrip())