From: Michael Tremer <michael.tremer@ipfire.org>
Date: Sun, 14 Sep 2014 19:54:13 +0000 (+0000)
Subject: Add runtime check for providers if all dependencies are met
X-Git-Tag: 005~8
X-Git-Url: http://git.ipfire.org/?p=ddns.git;a=commitdiff_plain;h=64d3fad4f0e7f6715f9fa77c92bd784f68395688

Add runtime check for providers if all dependencies are met
---

diff --git a/configure.ac b/configure.ac
index 124a562..a892095 100644
--- a/configure.ac
+++ b/configure.ac
@@ -54,12 +54,6 @@ AC_PROG_SED
 # Python
 AM_PATH_PYTHON([2.7])
 
-# BIND nsupdate
-AC_CHECK_TOOL([NSUPDATE], [nsupdate])
-if test -z "${NSUPDATE}"; then
-	AC_MSG_ERROR([*** nsupdate not found])
-fi
-
 save_LIBS="$LIBS"
 
 AC_CONFIG_FILES([
@@ -74,6 +68,4 @@ AC_MSG_RESULT([
 
 	prefix            : ${prefix}
 	sysconfdir        : ${sysconfdir}
-
-	nsupdate          : ${NSUPDATE}
 ])
diff --git a/src/ddns/__init__.py b/src/ddns/__init__.py
index 84b8c80..7f2729c 100644
--- a/src/ddns/__init__.py
+++ b/src/ddns/__init__.py
@@ -124,6 +124,12 @@ class DDNSCore(object):
 				logger.warning("Could not find provider '%s' for entry '%s'." % (provider, entry))
 				continue
 
+			# Check if the provider is actually supported and if there are
+			# some dependencies missing on this system.
+			if not provider.supported():
+				logger.warning("Provider '%s' is known, but not supported on this machine" % (provider.name))
+				continue
+
 			# Create an instance of the provider object with settings from the
 			# configuration file.
 			entry = provider(self, **settings)
diff --git a/src/ddns/providers.py b/src/ddns/providers.py
index b66afc5..2c54f5a 100644
--- a/src/ddns/providers.py
+++ b/src/ddns/providers.py
@@ -21,6 +21,7 @@
 
 import datetime
 import logging
+import os
 import subprocess
 import urllib2
 import xml.dom.minidom
@@ -84,6 +85,14 @@ class DDNSProvider(object):
 
 			_providers[provider.handle] = provider
 
+	@staticmethod
+	def supported():
+		"""
+			Should be overwritten to check if the system the code is running
+			on has all the required tools to support this provider.
+		"""
+		return True
+
 	def __init__(self, core, **settings):
 		self.core = core
 
@@ -406,6 +415,19 @@ class DDNSProviderBindNsupdate(DDNSProvider):
 
 	DEFAULT_TTL = 60
 
+	@staticmethod
+	def supported():
+		# Search if the nsupdate utility is available
+		paths = os.environ.get("PATH")
+
+		for path in paths.split(":"):
+			executable = os.path.join(path, "nsupdate")
+
+			if os.path.exists(executable):
+				return True
+
+		return False
+
 	def update(self):
 		scriptlet = self.__make_scriptlet()