Merge pull request #902 from projectcalico/awlc/alpine-missing-iface-fix

Resolve "Felix dies if interface missing" on Alpine
projectcalico · Nov 19, 2015 · 2a36f87 · 2a36f87
2 parents 3d2c9bc + fdfc50d
commit 2a36f87
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Showing 2 changed files with 19 additions and 6 deletions.
diff --git a/calico/felix/devices.py b/calico/felix/devices.py
@@ -91,7 +91,12 @@ def interface_exists(interface):
         futils.check_call(["ip", "link", "list", interface])
         return True
     except futils.FailedSystemCall as fsc:
-        if fsc.stderr.count("does not exist") != 0:
+        # If the interface doesn't exist, the error message varies by
+        # flavor of Linux:
+        #  * Ubuntu/RHEL: "Device 'XYZ' does not exist"
+        #  * Alpine:      "ip: can't find device 'XYZ'"
+        if ("does not exist" in fsc.stderr) or \
+           ("can't find device" in fsc.stderr):
             return False
         else:
             # An error other than does not exist; just pass on up

diff --git a/calico/felix/test/test_devices.py b/calico/felix/test/test_devices.py
@@ -79,12 +79,20 @@ def test_interface_exists(self):
         args = []
         retcode = 1
         stdout = ""
-        stderr = "Device \"%s\" does not exist." % tap
-        err = futils.FailedSystemCall("From test", args, retcode, stdout, stderr)
 
-        with mock.patch('calico.felix.futils.check_call', side_effect=err):
-            self.assertFalse(devices.interface_exists(tap))
-            futils.check_call.assert_called_with(["ip", "link", "list", tap])
+        # Check we correctly handle error messages for a missing interface,
+        # and do so for all supported flavors of Linux.
+        error_messages = [
+            "Device \"%s\" does not exist." % tap,  # Ubuntu/RHEL
+            "ip: can't find device '%s'" % tap,     # Alpine
+        ]
+
+        for stderr in error_messages:
+	    err = futils.FailedSystemCall("From test", args, retcode, stdout, stderr)
+
+	    with mock.patch('calico.felix.futils.check_call', side_effect=err):
+	        self.assertFalse(devices.interface_exists(tap))
+	        futils.check_call.assert_called_with(["ip", "link", "list", tap])
 
         with mock.patch('calico.felix.futils.check_call'):
             self.assertTrue(devices.interface_exists(tap))