3 from types import StringTypes, IntType, LongType
7 from PLC.Timestamp import Timestamp
8 from PLC.Faults import *
9 from PLC.Parameter import Parameter
14 Representation of a row in a database table. To use, optionally
15 instantiate with a dict of values. Update as you would a
16 dict. Commit to the database with sync().
19 # Set this to the name of the table that stores the row.
20 # e.g. table_name = "nodes"
23 # Set this to the name of the primary key of the table. It is
24 # assumed that the this key is a sequence if it is not set when
26 # e.g. primary_key="node_id"
29 # Set this to the names of tables that reference this table's
33 # Set this to a dict of the valid fields of this object and their
34 # types. Not all fields (e.g., joined fields) may be updated via
38 # The name of the view that extends objects with tags
39 # e.g. view_tags_name = "view_node_tags"
42 # Set this to the set of tags that can be returned by the Get function
45 def __init__(self, api, fields = {}):
46 dict.__init__(self, fields)
48 # run the class_init initializer once
50 if not hasattr(cls,'class_inited'):
52 cls.class_inited=True # actual value does not matter
56 Validates values. Will validate a value with a custom function
57 if a function named 'validate_[key]' exists.
60 # Warn about mandatory fields
61 mandatory_fields = self.api.db.fields(self.table_name, notnull = True, hasdef = False)
62 for field in mandatory_fields:
63 if not self.has_key(field) or self[field] is None:
64 raise PLCInvalidArgument, field + " must be specified and cannot be unset in class %s"%self.__class__.__name__
66 # Validate values before committing
67 for key, value in self.iteritems():
68 if value is not None and hasattr(self, 'validate_' + key):
69 validate = getattr(self, 'validate_' + key)
70 self[key] = validate(value)
72 def separate_types(self, items):
74 Separate a list of different typed objects.
75 Return a list for each type (ints, strs and dicts)
78 if isinstance(items, (list, tuple, set)):
79 ints = filter(lambda x: isinstance(x, (int, long)), items)
80 strs = filter(lambda x: isinstance(x, StringTypes), items)
81 dicts = filter(lambda x: isinstance(x, dict), items)
82 return (ints, strs, dicts)
84 raise PLCInvalidArgument, "Can only separate list types"
87 def associate(self, *args):
89 Provides a means for high level api calls to associate objects
90 using low level calls.
94 raise PLCInvalidArgumentCount, "auth, field, value must be specified"
95 elif hasattr(self, 'associate_' + args[1]):
96 associate = getattr(self, 'associate_'+args[1])
99 raise PLCInvalidArguemnt, "No such associate function associate_%s" % args[1]
101 def validate_timestamp (self, timestamp):
102 return Timestamp.sql_validate(timestamp)
104 def add_object(self, classobj, join_table, columns = None):
106 Returns a function that can be used to associate this object
110 def add(self, obj, columns = None, commit = True):
112 Associate with the specified object.
115 # Various sanity checks
116 assert isinstance(self, Row)
117 assert self.primary_key in self
118 assert join_table in self.join_tables
119 assert isinstance(obj, classobj)
120 assert isinstance(obj, Row)
121 assert obj.primary_key in obj
122 assert join_table in obj.join_tables
124 # By default, just insert the primary keys of each object
125 # into the join table.
127 columns = {self.primary_key: self[self.primary_key],
128 obj.primary_key: obj[obj.primary_key]}
131 for name, value in columns.iteritems():
132 params.append(self.api.db.param(name, value))
134 self.api.db.do("INSERT INTO %s (%s) VALUES(%s)" % \
135 (join_table, ", ".join(columns), ", ".join(params)),
143 add_object = classmethod(add_object)
145 def remove_object(self, classobj, join_table):
147 Returns a function that can be used to disassociate this
151 def remove(self, obj, commit = True):
153 Disassociate from the specified object.
156 assert isinstance(self, Row)
157 assert self.primary_key in self
158 assert join_table in self.join_tables
159 assert isinstance(obj, classobj)
160 assert isinstance(obj, Row)
161 assert obj.primary_key in obj
162 assert join_table in obj.join_tables
164 self_id = self[self.primary_key]
165 obj_id = obj[obj.primary_key]
167 self.api.db.do("DELETE FROM %s WHERE %s = %s AND %s = %s" % \
169 self.primary_key, self.api.db.param('self_id', self_id),
170 obj.primary_key, self.api.db.param('obj_id', obj_id)),
178 remove_object = classmethod(remove_object)
180 # convenience: check in dict (self.fields or self.tags) that a key is writable
182 def is_writable (key,value,dict):
183 # if not mentioned, assume it's writable (e.g. deleted ...)
184 if key not in dict: return True
185 # if mentioned but not linked to a Parameter object, idem
186 if not isinstance(dict[key], Parameter): return True
187 # if not marked ro, it's writable
188 if not dict[key].ro: return True
191 def db_fields(self, obj = None):
193 Return only those fields that can be set or updated directly
194 (i.e., those fields that are in the primary table (table_name)
195 for this object, and are not marked as a read-only Parameter.
198 if obj is None: obj = self
200 db_fields = self.api.db.fields(self.table_name)
201 return dict ( [ (key,value) for (key,value) in obj.items()
202 if key in db_fields and
203 Row.is_writable(key,value,self.fields) ] )
205 def tag_fields (self, obj=None):
207 Return the fields of obj that are mentioned in tags
209 if obj is None: obj=self
211 return dict ( [ (key,value) for (key,value) in obj.iteritems()
212 if key in self.tags and Row.is_writable(key,value,self.tags) ] )
214 # takes as input a list of columns, sort native fields from tags
215 # returns 2 dicts and one list : fields, tags, rejected
217 def parse_columns (cls, columns):
218 (fields,tags,rejected)=({},{},[])
219 for column in columns:
220 if column in cls.fields: fields[column]=cls.fields[column]
221 elif column in cls.tags: tags[column]=cls.tags[column]
222 else: rejected.append(column)
223 return (fields,tags,rejected)
225 # compute the 'accepts' part of a method, from a list of column names, and a fields dict
226 # use exclude=True to exclude the column names instead
227 # typically accepted_fields (Node.fields,['hostname','model',...])
229 def accepted_fields (update_columns, fields_dict, exclude=False):
231 for (k,v) in fields_dict.iteritems():
232 if (not exclude and k in update_columns) or (exclude and k not in update_columns):
236 # filter out user-provided fields that are not part of the declared acceptance list
237 # keep it separate from split_fields for simplicity
238 # typically check_fields (<user_provided_dict>,{'hostname':Parameter(str,...),'model':Parameter(..)...})
240 def check_fields (user_dict, accepted_fields):
241 # avoid the simple, but silent, version
242 # return dict ([ (k,v) for (k,v) in user_dict.items() if k in accepted_fields ])
244 for (k,v) in user_dict.items():
245 if k in accepted_fields: result[k]=v
246 else: raise PLCInvalidArgument ('Trying to set/change unaccepted key %s'%k)
249 # given a dict (typically passed to an Update method), we check and sort
250 # them against a list of dicts, e.g. [Node.fields, Node.related_fields]
251 # return is a list that contains n+1 dicts, last one has the rejected fields
253 def split_fields (fields, dicts):
255 for x in dicts: result.append({})
257 for (field,value) in fields.iteritems():
259 for i in range(len(dicts)):
260 candidate_dict=dicts[i]
261 if field in candidate_dict.keys():
262 result[i][field]=value
265 if not found: rejected[field]=value
266 result.append(rejected)
269 ### class initialization : create tag-dependent cross view if needed
271 def tagvalue_view_name (cls, tagname):
272 return "tagvalue_view_%s_%s"%(cls.primary_key,tagname)
275 def tagvalue_view_create_sql (cls,tagname):
277 returns a SQL sentence that creates a view named after the primary_key and tagname,
279 (*) column 1: primary_key
280 (*) column 2: actual tag value, renamed into tagname
283 if not cls.view_tags_name:
284 raise Exception, 'WARNING: class %s needs to set view_tags_name'%cls.__name__
286 table_name=cls.table_name
287 primary_key=cls.primary_key
288 view_tags_name=cls.view_tags_name
289 tagvalue_view_name=cls.tagvalue_view_name(tagname)
290 return 'CREATE OR REPLACE VIEW %(tagvalue_view_name)s ' \
291 'as SELECT %(table_name)s.%(primary_key)s,%(view_tags_name)s.value as "%(tagname)s" ' \
292 'from %(table_name)s right join %(view_tags_name)s using (%(primary_key)s) ' \
293 'WHERE tagname = \'%(tagname)s\';'%locals()
296 def class_init (cls,api):
297 cls.tagvalue_views_create (api)
300 def tagvalue_views_create (cls,api):
301 if not cls.tags: return
302 for tagname in cls.tags.keys():
303 api.db.do(cls.tagvalue_view_create_sql (tagname))
311 # Filter out fields that cannot be set or updated directly
312 # (and thus would not affect equality for the purposes of
313 # deciding if we should sync() or not).
315 y = self.db_fields(y)
316 return dict.__eq__(x, y)
318 def sync(self, commit = True, insert = None):
320 Flush changes back to the database.
323 # Validate all specified fields
326 # Filter out fields that cannot be set or updated directly
327 db_fields = self.db_fields()
329 # Parameterize for safety
330 keys = db_fields.keys()
331 values = [self.api.db.param(key, value) for (key, value) in db_fields.items()]
333 # If the primary key (usually an auto-incrementing serial
334 # identifier) has not been specified, or the primary key is the
335 # only field in the table, or insert has been forced.
336 if not self.has_key(self.primary_key) or \
337 keys == [self.primary_key] or \
340 # If primary key id is a serial int and it isnt included, get next id
341 if self.fields[self.primary_key].type in (IntType, LongType) and \
342 self.primary_key not in self:
343 pk_id = self.api.db.next_id(self.table_name, self.primary_key)
344 self[self.primary_key] = pk_id
345 db_fields[self.primary_key] = pk_id
346 keys = db_fields.keys()
347 values = [self.api.db.param(key, value) for (key, value) in db_fields.items()]
349 sql = "INSERT INTO %s (%s) VALUES (%s)" % \
350 (self.table_name, ", ".join(keys), ", ".join(values))
352 # Update existing row
353 columns = ["%s = %s" % (key, value) for (key, value) in zip(keys, values)]
354 sql = "UPDATE %s SET " % self.table_name + \
355 ", ".join(columns) + \
358 self.api.db.param(self.primary_key, self[self.primary_key]))
360 self.api.db.do(sql, db_fields)
365 def delete(self, commit = True):
367 Delete row from its primary table, and from any tables that
371 assert self.primary_key in self
373 for table in self.join_tables + [self.table_name]:
374 if isinstance(table, tuple):
378 key = self.primary_key
380 sql = "DELETE FROM %s WHERE %s = %s" % \
382 self.api.db.param(self.primary_key, self[self.primary_key]))
384 self.api.db.do(sql, self)
391 Representation of row(s) in a database table.
394 def __init__(self, api, classobj, columns = None):
396 self.classobj = classobj
400 columns = classobj.fields
403 (columns,tag_columns,rejected) = classobj.parse_columns(columns)
404 if not columns and not tag_columns:
405 raise PLCInvalidArgument, "No valid return fields specified for class %s"%classobj.__name__
407 raise PLCInvalidArgument, "unknown column(s) specified %r in %s"%(rejected,classobj.__name__)
409 self.columns = columns
410 self.tag_columns = tag_columns
412 def sync(self, commit = True):
414 Flush changes back to the database.
420 def selectall(self, sql, params = None):
422 Given a list of rows from the database, fill ourselves with
426 for row in self.api.db.selectall(sql, params):
427 obj = self.classobj(self.api, row)
430 def dict(self, key_field = None):
432 Return ourself as a dict keyed on key_field.
435 if key_field is None:
436 key_field = self.classobj.primary_key
438 return dict([(obj[key_field], obj) for obj in self])