First draft for leases

[plcapi.git] / PLC / Leases.py

diff --git a/PLC/Leases.py b/PLC/Leases.py
new file mode 100644 (file)
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+++ b/PLC/Leases.py
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+#
+# Functions for interacting with the leases table in the database
+#
+# $Id$
+# $URL$
+# Thierry Parmentelat -- INRIA
+#
+
+from datetime import datetime
+
+from PLC.Faults import *
+from PLC.Parameter import Parameter, Mixed
+from PLC.Filter import Filter
+from PLC.Table import Row, Table
+from PLC.Nodes import Node, Nodes
+from PLC.Slices import Slice, Slices
+from PLC.LeaseFilter import LeaseFilter
+from PLC.Timestamp import Timestamp
+
+class Lease(Row):
+    """
+    Representation of a row in the leases table. To use, optionally
+    instantiate with a dict of values. Update as you would a
+    dict. Commit to the database with sync().
+    """
+
+    table_name = 'leases'
+    primary_key = 'lease_id'
+    join_tables = [ ]
+    fields = {
+        # native
+        'lease_id': Parameter(int, "Lease identifier"),
+        't_from': Timestamp.Parameter("timeslot start"),
+        't_until': Timestamp.Parameter("timeslot end"),
+        'node_id': Node.fields['node_id'],
+        'slice_id': Slice.fields['slice_id'],
+
+        # derived
+        'hostname': Node.fields['hostname'],
+        'node_type': Node.fields['node_type'],
+        'name': Slice.fields['name'],
+        'site_id': Slice.fields['site_id'],
+        'duration': Parameter(int, "duration in seconds"),
+        'expired' : Parameter(bool, "time slot is over"),
+        }
+
+    related_fields = { }
+
+    # leases do not have arbitrary boundaries
+    # f_from and t_until are rounded to this period of time
+    # initial model is one hour
+    granularity = 60*60
+
+    def validate_time (self, timestamp, round_up):
+        # convert to long
+        timestamp = Timestamp.cast_long(timestamp)
+        # the trick for rounding up rather than down
+        if round_up: timestamp += (Lease.granularity-1)
+        # round down
+        timestamp = (timestamp/Lease.granularity) * Lease.granularity
+        # return a SQL string
+        return Timestamp.sql_validate_utc(timestamp)
+
+    # round UP 
+    def validate_t_from(self,timestamp):
+        return self.validate_time (timestamp, round_up=True)
+    # round DOWN 
+    def validate_t_until (self, timestamp):
+        return self.validate_time (timestamp, round_up=False)
+
+class Leases(Table):
+    """
+    Representation of row(s) from the leases table in the
+    database.
+    """
+
+    def __init__(self, api, lease_filter = None, columns = None):
+        Table.__init__(self, api, Lease, columns)
+
+        # the view that we're selecting upon: start with view_leases
+        view = "view_leases"
+        sql = "SELECT %s FROM %s WHERE true" % (", ".join(self.columns.keys()),view)
+
+
+        if lease_filter is not None:
+
+            if isinstance (lease_filter, int):
+                lease_filter = Filter (Lease.fields, {'lease_id': lease_filter})
+            elif isinstance(lease_filter, (list, tuple, set)):
+                lease_filter = Filter(Lease.fields, {'lease_id': lease_filter})
+            elif isinstance(lease_filter, dict):
+                lease_filter = LeaseFilter(Lease.fields, lease_filter)
+            else:
+                raise PLCInvalidArgument, "Wrong lease filter %r"%lease_filter
+            sql += " AND (%s) %s" % lease_filter.sql(api)
+
+        self.selectall(sql)