Switch to cobalt xmlrpc proxy code; should allow easier sync between bcfg and cobalt

git-svn-id: https://svn.mcs.anl.gov/repos/bcfg/trunk/bcfg2@1725 ce84e21b-d406-0410-9b95-82705330c041

2 files changed, 93 insertions, 1 deletions

diff --git a/src/lib/Client/Proxy.py b/src/lib/Client/Proxy.py
new file mode 100644
index 000000000..d300eac72
--- /dev/null
+++ b/src/lib/Client/Proxy.py
@@ -0,0 +1,92 @@
+'''Cobalt proxy provides client access to cobalt components'''
+__revision__ = '$Revision:$'
+
+import logging, socket, time, xmlrpclib, ConfigParser
+
+class CobaltComponentError(Exception):
+    '''This error signals component connection errors'''
+    pass
+
+class SafeProxy:
+    '''Wrapper for proxy'''
+    _cfile = ConfigParser.ConfigParser()
+    _cfile.read(['/etc/cobalt.conf'])
+    _components = _cfile._sections['components']
+    _authinfo = ('root', _cfile.get('communication', 'password'))
+    _retries = 4
+
+    def __init__(self, component, url=None):
+        self.component = component
+        self.log = logging.getLogger(component)
+        if url != None:
+            address = url
+        else:
+            address = self.__get_location(component)
+        try:
+            self.proxy = xmlrpclib.ServerProxy(address)
+        except IOError, io_error:
+            self.log.error("Invalid server URL %s: %s" % (address, io_error))
+            raise CobaltComponentError
+        except:
+            self.log.error("Failed to initialize xml-rpc", exc_info=1)
+
+    def run_method(self, method_name, method_args):
+        ''' Perform an XMLRPC invocation against the server'''
+        method = getattr(self.proxy, method_name)
+        for irs in range(self._retries):
+            try:
+                ret = apply(method, self._authinfo + method_args)
+                if irs > 0:
+                    self.log.warning("Required %d attempts to contact %s for operation %s" %
+                                     (irs, self.component, method_name))
+                self.log.debug("%s completed successfully" % (method_name))
+                return ret
+            except xmlrpclib.ProtocolError:
+                self.log.error("Server failure: Protocol Error")
+                raise xmlrpclib.Fault(20, "Server Failure")
+            except xmlrpclib.Fault:
+                self.log.debug("Operation %s completed with fault" % (method_name))
+                raise
+            except socket.error:
+                self.log.debug("Attempting %s (%d of %d) failed" % (method_name, (irs+1), self._retries))
+                time.sleep(0.5)                
+            except:
+                break
+        self.log.error("%s failed:\nCould not connect to %s" % (method_name, self.component))
+        
+    def __get_location(self, name):
+        '''Perform component location lookups if needed'''
+        if self._components.has_key(name):
+            return self._components[name]
+        slp = SafeProxy('service-location', url=self._cfile.get('components', 'service-location'))
+        try:
+            sdata = slp.run_method('LookupService',
+                                   ([{'tag':'location', 'name':name, 'url':'*'}],))
+        except xmlrpclib.Fault:
+            raise CobaltComponentError, "No Such Component"
+        if sdata:
+            curl = sdata[0]['url']
+            self._components[name] = curl
+            return curl
+            
+class ComponentProxy(SafeProxy):
+    '''Component Proxy instantiates a SafeProxy to a component and registers local functions
+    based on its definition'''
+    name = 'dummy'
+    methods = []
+
+    def __init__(self, url=None):
+        SafeProxy.__init__(self, self.name, url)
+        for method in self.methods:
+            setattr(self, method, eval('lambda *x:self.run_method(method, x)',
+                                       {'self':self, 'method':method}))
+
+class service_location(ComponentProxy):
+    '''service-location component-specific proxy'''
+    name = 'service-location'
+    methods = ['AssertService', 'LookupService', 'DeassertService']
+
+class process_manager(ComponentProxy):
+    '''process manager specific component proxy'''
+    name = 'process-manager'
+    methods = ['CreateProcessGroup', 'GetProcessGroup']
diff --git a/src/lib/Client/__init__.py b/src/lib/Client/__init__.py
index 0435249f7..bfdbc0e98 100644
--- a/src/lib/Client/__init__.py
+++ b/src/lib/Client/__init__.py
@@ -1,4 +1,4 @@
 '''This contains all Bcfg2 Client modules'''
 __revision__ = '$Revision$'
 
-__all__ = ["Toolset", "Debian", "Solaris", "Redhat", "Gentoo"]
+__all__ = ["Proxy", "Toolset", "Debian", "Solaris", "Redhat", "Gentoo"]