from types import StringTypes, IntType, LongType import time import calendar from PLC.Timestamp import Timestamp from PLC.Faults import * from PLC.Parameter import Parameter class Row(dict): """ Representation of a row in a database table. To use, optionally instantiate with a dict of values. Update as you would a dict. Commit to the database with sync(). """ # Set this to the name of the table that stores the row. # e.g. table_name = "nodes" table_name = None # Set this to the name of the primary key of the table. It is # assumed that the this key is a sequence if it is not set when # sync() is called. # e.g. primary_key="node_id" primary_key = None # Set this to the names of tables that reference this table's # primary key. join_tables = [] # Set this to a dict of the valid fields of this object and their # types. Not all fields (e.g., joined fields) may be updated via # sync(). fields = {} # The name of the view that extends objects with tags # e.g. view_tags_name = "view_node_tags" view_tags_name = None # Set this to the set of tags that can be returned by the Get function tags = {} def __init__(self, api, fields = {}): dict.__init__(self, fields) self.api = api # run the class_init initializer once cls=self.__class__ if not hasattr(cls,'class_inited'): cls.class_init (api) cls.class_inited=True # actual value does not matter def validate(self): """ Validates values. Will validate a value with a custom function if a function named 'validate_[key]' exists. """ # Warn about mandatory fields mandatory_fields = self.api.db.fields(self.table_name, notnull = True, hasdef = False) for field in mandatory_fields: if not self.has_key(field) or self[field] is None: raise PLCInvalidArgument, field + " must be specified and cannot be unset in class %s"%self.__class__.__name__ # Validate values before committing for key, value in self.iteritems(): if value is not None and hasattr(self, 'validate_' + key): validate = getattr(self, 'validate_' + key) self[key] = validate(value) def separate_types(self, items): """ Separate a list of different typed objects. Return a list for each type (ints, strs and dicts) """ if isinstance(items, (list, tuple, set)): ints = filter(lambda x: isinstance(x, (int, long)), items) strs = filter(lambda x: isinstance(x, StringTypes), items) dicts = filter(lambda x: isinstance(x, dict), items) return (ints, strs, dicts) else: raise PLCInvalidArgument, "Can only separate list types" def associate(self, *args): """ Provides a means for high level api calls to associate objects using low level calls. """ if len(args) < 3: raise PLCInvalidArgumentCount, "auth, field, value must be specified" elif hasattr(self, 'associate_' + args[1]): associate = getattr(self, 'associate_'+args[1]) associate(*args) else: raise PLCInvalidArguemnt, "No such associate function associate_%s" % args[1] def validate_timestamp (self, timestamp): return Timestamp.sql_validate(timestamp) def add_object(self, classobj, join_table, columns = None): """ Returns a function that can be used to associate this object with another. """ def add(self, obj, columns = None, commit = True): """ Associate with the specified object. """ # Various sanity checks assert isinstance(self, Row) assert self.primary_key in self assert join_table in self.join_tables assert isinstance(obj, classobj) assert isinstance(obj, Row) assert obj.primary_key in obj assert join_table in obj.join_tables # By default, just insert the primary keys of each object # into the join table. if columns is None: columns = {self.primary_key: self[self.primary_key], obj.primary_key: obj[obj.primary_key]} params = [] for name, value in columns.iteritems(): params.append(self.api.db.param(name, value)) self.api.db.do("INSERT INTO %s (%s) VALUES(%s)" % \ (join_table, ", ".join(columns), ", ".join(params)), columns) if commit: self.api.db.commit() return add add_object = classmethod(add_object) def remove_object(self, classobj, join_table): """ Returns a function that can be used to disassociate this object with another. """ def remove(self, obj, commit = True): """ Disassociate from the specified object. """ assert isinstance(self, Row) assert self.primary_key in self assert join_table in self.join_tables assert isinstance(obj, classobj) assert isinstance(obj, Row) assert obj.primary_key in obj assert join_table in obj.join_tables self_id = self[self.primary_key] obj_id = obj[obj.primary_key] self.api.db.do("DELETE FROM %s WHERE %s = %s AND %s = %s" % \ (join_table, self.primary_key, self.api.db.param('self_id', self_id), obj.primary_key, self.api.db.param('obj_id', obj_id)), locals()) if commit: self.api.db.commit() return remove remove_object = classmethod(remove_object) # convenience: check in dict (self.fields or self.tags) that a key is writable @staticmethod def is_writable (key,value,dict): # if not mentioned, assume it's writable (e.g. deleted ...) if key not in dict: return True # if mentioned but not linked to a Parameter object, idem if not isinstance(dict[key], Parameter): return True # if not marked ro, it's writable if not dict[key].ro: return True return False def db_fields(self, obj = None): """ Return only those fields that can be set or updated directly (i.e., those fields that are in the primary table (table_name) for this object, and are not marked as a read-only Parameter. """ if obj is None: obj = self db_fields = self.api.db.fields(self.table_name) return dict ( [ (key, value) for (key, value) in obj.items() if key in db_fields and Row.is_writable(key, value, self.fields) ] ) def tag_fields (self, obj=None): """ Return the fields of obj that are mentioned in tags """ if obj is None: obj=self return dict ( [ (key,value) for (key,value) in obj.iteritems() if key in self.tags and Row.is_writable(key,value,self.tags) ] ) # takes as input a list of columns, sort native fields from tags # returns 2 dicts and one list : fields, tags, rejected @classmethod def parse_columns (cls, columns): (fields,tags,rejected)=({},{},[]) for column in columns: if column in cls.fields: fields[column]=cls.fields[column] elif column in cls.tags: tags[column]=cls.tags[column] else: rejected.append(column) return (fields,tags,rejected) # compute the 'accepts' part of a method, from a list of column names, and a fields dict # use exclude=True to exclude the column names instead # typically accepted_fields (Node.fields,['hostname','model',...]) @staticmethod def accepted_fields (update_columns, fields_dict, exclude=False): result={} for (k,v) in fields_dict.iteritems(): if (not exclude and k in update_columns) or (exclude and k not in update_columns): result[k]=v return result # filter out user-provided fields that are not part of the declared acceptance list # keep it separate from split_fields for simplicity # typically check_fields (,{'hostname':Parameter(str,...),'model':Parameter(..)...}) @staticmethod def check_fields (user_dict, accepted_fields): # avoid the simple, but silent, version # return dict ([ (k,v) for (k,v) in user_dict.items() if k in accepted_fields ]) result={} for (k,v) in user_dict.items(): if k in accepted_fields: result[k]=v else: raise PLCInvalidArgument ('Trying to set/change unaccepted key %s'%k) return result # given a dict (typically passed to an Update method), we check and sort # them against a list of dicts, e.g. [Node.fields, Node.related_fields] # return is a list that contains n+1 dicts, last one has the rejected fields @staticmethod def split_fields (fields, dicts): result=[] for x in dicts: result.append({}) rejected={} for (field,value) in fields.iteritems(): found=False for i in range(len(dicts)): candidate_dict=dicts[i] if field in candidate_dict.keys(): result[i][field]=value found=True break if not found: rejected[field]=value result.append(rejected) return result ### class initialization : create tag-dependent cross view if needed @classmethod def tagvalue_view_name (cls, tagname): return "tagvalue_view_%s_%s"%(cls.primary_key,tagname) @classmethod def tagvalue_view_create_sql (cls,tagname): """ returns a SQL sentence that creates a view named after the primary_key and tagname, with 2 columns (*) column 1: primary_key (*) column 2: actual tag value, renamed into tagname """ if not cls.view_tags_name: raise Exception, 'WARNING: class %s needs to set view_tags_name'%cls.__name__ table_name=cls.table_name primary_key=cls.primary_key view_tags_name=cls.view_tags_name tagvalue_view_name=cls.tagvalue_view_name(tagname) return 'CREATE OR REPLACE VIEW %(tagvalue_view_name)s ' \ 'as SELECT %(table_name)s.%(primary_key)s,%(view_tags_name)s.value as "%(tagname)s" ' \ 'from %(table_name)s right join %(view_tags_name)s using (%(primary_key)s) ' \ 'WHERE tagname = \'%(tagname)s\';'%locals() @classmethod def class_init (cls,api): cls.tagvalue_views_create (api) @classmethod def tagvalue_views_create (cls,api): if not cls.tags: return for tagname in cls.tags.keys(): api.db.do(cls.tagvalue_view_create_sql (tagname)) api.db.commit() def __eq__(self, y): """ Compare two objects. """ # Filter out fields that cannot be set or updated directly # (and thus would not affect equality for the purposes of # deciding if we should sync() or not). x = self.db_fields() y = self.db_fields(y) return dict.__eq__(x, y) # validate becomes optional on sept. 2010 # we find it useful to use DeletePerson on duplicated entries def sync(self, commit = True, insert = None, validate=True): """ Flush changes back to the database. """ # Validate all specified fields if validate: self.validate() # Filter out fields that cannot be set or updated directly db_fields = self.db_fields() # Parameterize for safety keys = db_fields.keys() values = [self.api.db.param(key, value) for (key, value) in db_fields.items()] # If the primary key (usually an auto-incrementing serial # identifier) has not been specified, or the primary key is the # only field in the table, or insert has been forced. if not self.has_key(self.primary_key) or \ keys == [self.primary_key] or \ insert is True: # If primary key id is a serial int and it isnt included, get next id if self.fields[self.primary_key].type in (IntType, LongType) and \ self.primary_key not in self: pk_id = self.api.db.next_id(self.table_name, self.primary_key) self[self.primary_key] = pk_id db_fields[self.primary_key] = pk_id keys = db_fields.keys() values = [self.api.db.param(key, value) for (key, value) in db_fields.items()] # Insert new row sql = "INSERT INTO %s (%s) VALUES (%s)" % \ (self.table_name, ", ".join(keys), ", ".join(values)) else: # Update existing row columns = ["%s = %s" % (key, value) for (key, value) in zip(keys, values)] sql = "UPDATE {} SET {} WHERE {} = {}"\ .format(self.table_name, ", ".join(columns), self.primary_key, self.api.db.param(self.primary_key, self[self.primary_key])) self.api.db.do(sql, db_fields) if commit: self.api.db.commit() def delete(self, commit = True): """ Delete row from its primary table, and from any tables that reference it. """ assert self.primary_key in self for table in self.join_tables + [self.table_name]: if isinstance(table, tuple): key = table[1] table = table[0] else: key = self.primary_key sql = "DELETE FROM %s WHERE %s = %s" % \ (table, key, self.api.db.param(self.primary_key, self[self.primary_key])) self.api.db.do(sql, self) if commit: self.api.db.commit() class Table(list): """ Representation of row(s) in a database table. """ def __init__(self, api, classobj, columns = None): self.api = api self.classobj = classobj self.rows = {} if columns is None: columns = classobj.fields tag_columns={} else: (columns,tag_columns,rejected) = classobj.parse_columns(columns) if not columns and not tag_columns: raise PLCInvalidArgument, "No valid return fields specified for class %s"%classobj.__name__ if rejected: raise PLCInvalidArgument, "unknown column(s) specified %r in %s"%(rejected,classobj.__name__) self.columns = columns self.tag_columns = tag_columns def sync(self, commit = True): """ Flush changes back to the database. """ for row in self: row.sync(commit) def selectall(self, sql, params = None): """ Given a list of rows from the database, fill ourselves with Row objects. """ for row in self.api.db.selectall(sql, params): obj = self.classobj(self.api, row) self.append(obj) def dict(self, key_field = None): """ Return ourself as a dict keyed on key_field. """ if key_field is None: key_field = self.classobj.primary_key return dict([(obj[key_field], obj) for obj in self])