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-- listen trigger:
-- create trigger triga_nimi after insert or update on customer
-- for each row execute procedure pgq.sqltriga('qname');
-- redirect trigger:
-- create trigger triga_nimi after insert or update on customer
-- for each row execute procedure pgq.sqltriga('qname', 'ret=SKIP');
create or replace function pgq.sqltriga()
returns trigger as $$
# -- ----------------------------------------------------------------------
# -- Function: pgq.sqltriga()
# --
# -- Trigger function that puts row data in partial SQL form into queue.
# --
# -- Parameters:
# -- arg1 - queue name
# -- arg2 - optional urlencoded options
# --
# -- Extra options:
# --
# -- ret - return value for function OK/SKIP
# -- pkey - override pkey fields, can be functions
# -- ignore - comma separated field names to ignore
# --
# -- Queue event fields:
# -- ev_type - I/U/D
# -- ev_data - partial SQL statement
# -- ev_extra1 - table name
# --
# -- ----------------------------------------------------------------------
# this triger takes 1 or 2 args:
# queue_name - destination queue
# args - urlencoded dict of options:
# ret - return value: OK/SKIP
# pkey - comma-separated col names or funcs on cols
# simple: pkey=user,orderno
# hashed: pkey=user,hashtext(user)
# ignore - comma-separated col names to ignore
# on first call init stuff
if not 'init_done' in SD:
# find table name plan
q = "SELECT n.nspname || '.' || c.relname AS table_name"\
" FROM pg_namespace n, pg_class c"\
" WHERE n.oid = c.relnamespace AND c.oid = $1"
SD['name_plan'] = plpy.prepare(q, ['oid'])
# find key columns plan
q = "SELECT k.attname FROM pg_index i, pg_attribute k"\
" WHERE i.indrelid = $1 AND k.attrelid = i.indexrelid"\
" AND i.indisprimary AND k.attnum > 0 AND NOT k.attisdropped"\
" ORDER BY k.attnum"
SD['key_plan'] = plpy.prepare(q, ['oid'])
# data insertion
q = "SELECT pgq.insert_event($1, $2, $3, $4, null, null, null)"
SD['ins_plan'] = plpy.prepare(q, ['text', 'text', 'text', 'text'])
# shorter tags
SD['op_map'] = {'INSERT': 'I', 'UPDATE': 'U', 'DELETE': 'D'}
# quoting
from psycopg import QuotedString
def quote(s):
if s is None:
return "null"
s = str(s)
return str(QuotedString(s))
s = s.replace('\\', '\\\\')
s = s.replace("'", "''")
return "'%s'" % s
# TableInfo class
import re, urllib
class TableInfo:
func_rc = re.compile("([^(]+) [(] ([^)]+) [)]", re.I | re.X)
def __init__(self, table_oid, options_txt):
res = plpy.execute(SD['name_plan'], [table_oid])
self.name = res[0]['table_name']
self.parse_options(options_txt)
self.load_pkey()
def recheck(self, options_txt):
if self.options_txt == options_txt:
return
self.parse_options(options_txt)
self.load_pkey()
def parse_options(self, options_txt):
self.options = {'ret': 'OK'}
if options_txt:
for s in options_txt.split('&'):
k, v = s.split('=', 1)
self.options[k] = urllib.unquote_plus(v)
self.options_txt = options_txt
def load_pkey(self):
self.pkey_list = []
if not 'pkey' in self.options:
res = plpy.execute(SD['key_plan'], [table_oid])
for krow in res:
col = krow['attname']
expr = col + "=%s"
self.pkey_list.append( (col, expr) )
else:
for a_pk in self.options['pkey'].split(','):
m = self.func_rc.match(a_pk)
if m:
col = m.group(2)
fn = m.group(1)
expr = "%s(%s) = %s(%%s)" % (fn, col, fn)
else:
# normal case
col = a_pk
expr = col + "=%s"
self.pkey_list.append( (col, expr) )
if len(self.pkey_list) == 0:
plpy.error('sqltriga needs primary key on table')
def get_insert_stmt(self, new):
col_list = []
val_list = []
for k, v in new.items():
col_list.append(k)
val_list.append(quote(v))
return "(%s) values (%s)" % (",".join(col_list), ",".join(val_list))
def get_update_stmt(self, old, new):
chg_list = []
for k, v in new.items():
ov = old[k]
if v == ov:
continue
chg_list.append("%s=%s" % (k, quote(v)))
if len(chg_list) == 0:
pk = self.pkey_list[0][0]
chg_list.append("%s=%s" % (pk, quote(new[pk])))
return "%s where %s" % (",".join(chg_list), self.get_pkey_expr(new))
def get_pkey_expr(self, data):
exp_list = []
for col, exp in self.pkey_list:
exp_list.append(exp % quote(data[col]))
return " and ".join(exp_list)
SD['TableInfo'] = TableInfo
# cache some functions
def proc_insert(tbl):
return tbl.get_insert_stmt(TD['new'])
def proc_update(tbl):
return tbl.get_update_stmt(TD['old'], TD['new'])
def proc_delete(tbl):
return tbl.get_pkey_expr(TD['old'])
SD['event_func'] = {
'I': proc_insert,
'U': proc_update,
'D': proc_delete,
}
# remember init
SD['init_done'] = 1
# load args
table_oid = TD['relid']
queue_name = TD['args'][0]
if len(TD['args']) > 1:
options_str = TD['args'][1]
else:
options_str = ''
# load & cache table data
if table_oid in SD:
tbl = SD[table_oid]
tbl.recheck(options_str)
else:
tbl = SD['TableInfo'](table_oid, options_str)
SD[table_oid] = tbl
# generate payload
op = SD['op_map'][TD['event']]
data = SD['event_func'][op](tbl)
# insert event
plpy.execute(SD['ins_plan'], [queue_name, op, data, tbl.name])
# done
return tbl.options['ret']
$$ language plpythonu;
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