X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=sfa%2Fstorage%2Falchemy.py;h=de2e55d9296df31de30a9cdfcdf31a803ef30759;hb=78e5fb75e3793ae9dfce7f1bbd4a2b0f27b7ecc6;hp=dff6151f7eac85302cdb1de999b99b979d3ce139;hpb=8b2002c13e2c83e49976b5667b8345a977300dde;p=sfa.git

diff --git a/sfa/storage/alchemy.py b/sfa/storage/alchemy.py
index dff6151f..de2e55d9 100644
--- a/sfa/storage/alchemy.py
+++ b/sfa/storage/alchemy.py
@@ -1,87 +1,83 @@
 from sqlalchemy import create_engine
-
 from sqlalchemy.orm import sessionmaker
-Session=sessionmaker ()
-session=Session(bind=engine)
-#session.configure(bind=engine)
 
-from sqlalchemy.ext.declarative import declarative_base
 from sqlalchemy import Column, Integer, String
-from sqlalchemy.orm import relationship, backref
 from sqlalchemy import ForeignKey
 
-from sfa.util.sfalogger import logger
+from sfa.util.sfalogging import logger
+
+# this module is designed to be loaded when the configured db server is reachable
+# OTOH model can be loaded from anywhere including the client-side
 
-Base=declarative_base()
 
-class DB:
+class Alchemy:
 
-    def __init__ (self, config):
-        dbname="sfa"
+    def __init__(self, config):
+        dbname = "sfa"
         # will be created lazily on-demand
-        self.session = None
+        self._session = None
         # the former PostgreSQL.py used the psycopg2 directly and was doing
-        #self.connection.set_client_encoding("UNICODE")
+        # self.connection.set_client_encoding("UNICODE")
         # it's unclear how to achieve this in sqlalchemy, nor if it's needed at all
         # http://www.sqlalchemy.org/docs/dialects/postgresql.html#unicode
         # we indeed have /var/lib/pgsql/data/postgresql.conf where
         # this setting is unset, it might be an angle to tweak that if need be
         # try a unix socket first - omitting the hostname does the trick
-        unix_desc = "postgresql+psycopg2://%s:%s@:%s/%s"%\
-            (config.SFA_DB_USER,config.SFA_DB_PASSWORD,config.SFA_DB_PORT,dbname)
+        unix_url = "postgresql+psycopg2://%s:%s@:%s/%s" %\
+            (config.SFA_DB_USER, config.SFA_DB_PASSWORD, config.SFA_DB_PORT, dbname)
         # the TCP fallback method
-        tcp_desc = "postgresql+psycopg2://%s:%s@%s:%s/%s"%\
-            (config.SFA_DB_USER,config.SFA_DB_PASSWORD,config.SFA_DB_HOST,config.SFA_DB_PORT,dbname)
-        for desc in [ unix_desc, tcp_desc ] :
+        tcp_url = "postgresql+psycopg2://%s:%s@%s:%s/%s" %\
+            (config.SFA_DB_USER, config.SFA_DB_PASSWORD,
+             config.SFA_DB_HOST, config.SFA_DB_PORT, dbname)
+        for url in [unix_url, tcp_url]:
             try:
-                self.engine = create_engine (engine_desc)
+                logger.debug("Trying db URL %s" % url)
+                self.engine = create_engine(url)
                 self.check()
+                self.url = url
                 return
             except:
                 pass
-        self.engine=None
-        raise Exception,"Could not connect to database"
-                
+        self.engine = None
+        raise Exception("Could not connect to database %s as %s with psycopg2" % (
+            dbname, config.SFA_DB_USER))
 
     # expects boolean True: debug is ON or False: debug is OFF
-    def debug (self, echo):
-        self.engine.echo=echo
-
-    def check (self):
-        self.engine.execute ("select 1").scalar()
+    def debug(self, echo):
+        self.engine.echo = echo
 
-    # create schema
-    def create_schema (self):
-        return Base.metadata.create_all(self.engine)
+    def check(self):
+        self.engine.execute("select 1").scalar()
 
-    # does a complete wipe of the schema, use with care
-    def drop_schema (self):
-        return Base.metadata.drop_all(self.engine)
-
-    def session (self):
+    def global_session(self):
         if self._session is None:
-            Session=sessionmaker ()
-            self._session=Session(bind=self.engine)
+            Session = sessionmaker()
+            self._session = Session(bind=self.engine)
+            logger.debug('alchemy.global_session created session %s' %
+                         self._session)
         return self._session
 
-    def close_session (self):
-        if self._session is None: return
+    def close_global_session(self):
+        if self._session is None:
+            return
+        logger.debug('alchemy.close_global_session %s' % self._session)
         self._session.close()
-        self._session=None
+        self._session = None
+
+    # create a dbsession to be managed separately
+    def session(self):
+        Session = sessionmaker()
+        session = Session(bind=self.engine)
+        logger.debug('alchemy.session created session %s' % session)
+        return session
 
-    def commit (self):
-        self.session().commit()
-            
-    def insert (self, stuff, commit=False):
-        if isinstance (stuff,list):
-            self.session().add_all(stuff)
-        else:
-            self.session().add(obj)
+    def close_session(self, session):
+        logger.debug('alchemy.close_session closed session %s' % session)
+        session.close()
 
-    # for compat with the previous PostgreSQL stuff
-    def update (self, record):
-        self.commit()
+####################
+from sfa.util.config import Config
 
-    def remove (self, record):
-        del record
-        self.commit()
+alchemy = Alchemy(Config())
+engine = alchemy.engine
+global_dbsession = alchemy.global_session()