/
setup.go
162 lines (148 loc) · 4.22 KB
/
setup.go
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package pgtl
import (
"context"
"database/sql"
"fmt"
"strings"
"time"
"github.com/lib/pq"
)
// Table struct for table details
type Table struct {
Name string
Schema string
}
// Trigger Details
const (
ListenEvent = `event`
TriggerFunction = `notifier`
Trigger = `notifier_trigger`
)
// CreateTriggerFunction creates triggered function
func CreateTriggerFunction(ctx context.Context, db *sql.DB) error {
const createTriggerFunQuery = `
CREATE OR REPLACE FUNCTION notifier() RETURNS TRIGGER AS
$body$
DECLARE
message json;
old_row json;
new_row json;
data json;
BEGIN
IF (TG_OP = 'UPDATE') THEN
old_row = row_to_json(OLD);
new_row = row_to_json(NEW);
data = json_build_object('old row', old_row,'new row', new_row);
ELSIF (TG_OP = 'DELETE') THEN
old_row = row_to_json(OLD);
data = json_build_object('old row', old_row);
ELSIF (TG_OP = 'INSERT') THEN
new_row = row_to_json(NEW);
data = json_build_object('new row', new_row);
END IF;
message = json_build_object(
'table_name', TG_TABLE_NAME,
'schema_name', TG_TABLE_SCHEMA,
'operation', TG_OP,
'data', data
);
PERFORM pg_notify('event',message::text);
RETURN NULL;
END;
$body$
LANGUAGE plpgsql;`
if _, err := db.ExecContext(ctx, createTriggerFunQuery); err != nil {
return err
}
return nil
}
// TablesInDatabase returns list of tables in connected database
func TablesInDatabase(ctx context.Context, db *sql.DB) ([]*Table, error) {
const query = `SELECT array_agg(table_schema || '.' || table_name)
FROM information_schema.tables WHERE
table_schema != 'pg_catalog' AND table_schema != 'information_schema';`
list := make([]string, 0, 10)
if err := db.QueryRowContext(ctx, query).Scan(pq.Array(&list)); err != nil {
return nil, err
}
tablesList := make([]*Table, 0, len(list))
for _, l := range list {
t := strings.Split(l, ".")
tablesList = append(tablesList, &Table{t[1], t[0]})
}
return tablesList, nil
}
// TriggerSomeTables adds triggers to the provided tables
func TriggerSomeTables(ctx context.Context, db *sql.DB, tables []*Table) error {
const dropTrigger = `DROP TRIGGER IF EXISTS notifier_trigger ON `
const triggerQuerry1stHalf = `
CREATE TRIGGER notifier_trigger
AFTER INSERT OR UPDATE OR DELETE ON `
const triggerQuerry2ndHalf = `
FOR EACH ROW EXECUTE PROCEDURE notifier();`
tx, err := db.BeginTx(ctx, nil)
if err != nil {
return err
}
defer tx.Rollback()
for _, tb := range tables {
if _, err := tx.ExecContext(ctx, fmt.Sprintf("%s%s.%s;", dropTrigger, tb.Schema, tb.Name)); err != nil {
return err
}
query := fmt.Sprintf("%s%s.%s%s;", triggerQuerry1stHalf, tb.Schema, tb.Name, triggerQuerry2ndHalf)
if _, err := tx.ExecContext(ctx, query); err != nil {
return err
}
}
if err := tx.Commit(); err != nil {
return err
}
return nil
}
// TriggerAllTables adds triggers to all the tables in the connected database
func TriggerAllTables(ctx context.Context, db *sql.DB) error {
tables, err := TablesInDatabase(ctx, db)
if err != nil {
return err
}
return TriggerSomeTables(ctx, db, tables)
}
// SetupEverything sets everything up for the whole database to notify logs
func SetupEverything(ctx context.Context, dbConfig string) (*pq.Listener, error) {
db, err := sql.Open("postgres", dbConfig)
if err != nil {
return nil, fmt.Errorf("connection not open | %v", err.Error())
}
if err = db.Ping(); err != nil {
return nil, err
}
if err := CreateTriggerFunction(ctx, db); err != nil {
return nil, err
}
if err := TriggerAllTables(ctx, db); err != nil {
return nil, err
}
ls := pq.NewListener(dbConfig, 15*time.Second, time.Minute, func(event pq.ListenerEventType, err error) {
if err != nil {
panic(fmt.Errorf("%v with ListenerEventType = %v", err.Error(), event))
}
})
if err := ls.Listen(ListenEvent); err != nil {
return nil, fmt.Errorf("event failed to listen | %v", err)
}
return ls, nil
}
// Listen ...
func Listen(ls *pq.Listener) error {
if err := ls.Listen(ListenEvent); err != nil {
return fmt.Errorf("event failed to listen | %v", err)
}
return nil
}
// Unlisten ...
func Unlisten(ls *pq.Listener) error {
if err := ls.Unlisten(ListenEvent); err != nil {
return fmt.Errorf("event failed to unlisten | %v", err)
}
return nil
}