connector.go•8.36 kB
package postgres
import (
"context"
"fmt"
"strings"
"github.com/centralmind/gateway/connectors"
"database/sql"
"github.com/centralmind/gateway/castx"
"github.com/centralmind/gateway/model"
"github.com/jackc/pgx/v4/stdlib"
"github.com/jmoiron/sqlx"
"golang.org/x/xerrors"
)
func init() {
connectors.Register[Config](func(cfg Config) (connectors.Connector, error) {
c, err := cfg.MakeConfig()
if err != nil {
return nil, xerrors.Errorf("unable to prepare pg config: %w", err)
}
db := sqlx.NewDb(stdlib.OpenDB(*c), "pgx")
return &Connector{
config: cfg,
db: db,
base: &connectors.BaseConnector{DB: db},
}, nil
})
connectors.RegisterAlias("postgres", "postgresql")
}
// Connector implements the connectors.Connector interface for PostgreSQL
type Connector struct {
config Config
db *sqlx.DB
base *connectors.BaseConnector
}
func (c Connector) Config() connectors.Config {
return c.config
}
// GuessColumnType implements TypeGuesser interface for PostgreSQL
func (c *Connector) GuessColumnType(sqlType string) model.ColumnType {
upperType := strings.ToUpper(sqlType)
// Array types (check first as they contain other type names)
if strings.Contains(upperType, "[]") || strings.Contains(upperType, "ARRAY") {
return model.TypeArray
}
// Object types
switch upperType {
case "JSON", "JSONB":
return model.TypeObject
}
// String types
switch upperType {
case "VARCHAR", "CHAR", "TEXT", "NAME", "BPCHAR", "BYTEA", "UUID", "XML", "CITEXT",
"CHARACTER", "CHARACTER VARYING", "NCHAR", "NVARCHAR":
return model.TypeString
}
// Numeric types
switch upperType {
case "DECIMAL", "NUMERIC", "REAL", "DOUBLE PRECISION", "MONEY":
return model.TypeNumber
}
// Integer types
switch upperType {
case "INT4", "INT8", "SMALLINT", "INTEGER", "BIGINT", "SMALLSERIAL", "SERIAL", "BIGSERIAL":
return model.TypeInteger
}
// Boolean type
switch upperType {
case "BOOLEAN", "BOOL":
return model.TypeBoolean
}
// Date/Time types
switch upperType {
case "DATE", "TIME", "TIMETZ", "TIMESTAMP", "TIMESTAMPTZ", "INTERVAL":
return model.TypeDatetime
}
// Default to string for unknown types
return model.TypeString
}
// InferResultColumns returns column information for the given query
func (c *Connector) InferResultColumns(ctx context.Context, query string) ([]model.ColumnSchema, error) {
return c.base.InferResultColumns(ctx, query, c)
}
func (c Connector) Sample(ctx context.Context, table model.Table) ([]map[string]any, error) {
tx, err := c.db.BeginTxx(ctx, &sql.TxOptions{
ReadOnly: true,
})
if err != nil {
return nil, xerrors.Errorf("BeginTx failed with error: %w", err)
}
defer tx.Commit()
rows, err := tx.NamedQuery(fmt.Sprintf("SELECT * FROM %s LIMIT 5", table.Name), map[string]any{})
if err != nil {
return nil, xerrors.Errorf("unable to query db: %w", err)
}
defer rows.Close()
res := make([]map[string]any, 0, 5)
for rows.Next() {
row := map[string]any{}
if err := rows.MapScan(row); err != nil {
return nil, xerrors.Errorf("unable to scan row: %w", err)
}
res = append(res, row)
}
return res, nil
}
func (c Connector) Discovery(ctx context.Context, tablesList []string) ([]model.Table, error) {
tx, err := c.base.DB.BeginTxx(ctx, &sql.TxOptions{
ReadOnly: c.Config().Readonly(),
})
if err != nil {
return nil, xerrors.Errorf("BeginTx failed with error: %w", err)
}
defer tx.Commit()
// Create a map for quick lookups if tablesList is provided
tableSet := make(map[string]bool)
if len(tablesList) > 0 {
for _, table := range tablesList {
tableSet[table] = true
}
}
var query string
var args []interface{}
if len(tablesList) > 0 {
// If specific tables are requested, only query those
placeholders := make([]string, len(tablesList))
args = make([]interface{}, len(tablesList))
for i, table := range tablesList {
placeholders[i] = fmt.Sprintf("$%d", i+1)
args[i] = table
}
query = fmt.Sprintf(`
SELECT table_name, table_schema
FROM information_schema.tables
WHERE table_type = 'BASE TABLE'
AND table_name IN (%s)
`, strings.Join(placeholders, ","))
} else {
// Otherwise, query all tables
query = `
SELECT table_name, table_schema
FROM information_schema.tables
WHERE table_type = 'BASE TABLE'
`
}
rows, err := tx.QueryContext(ctx, query, args...)
if err != nil {
return nil, err
}
defer rows.Close()
var tables []model.Table
for rows.Next() {
var tableName, tableSchema string
if err := rows.Scan(&tableName, &tableSchema); err != nil {
return nil, err
}
if c.config.Schema != "" {
if tableSchema != c.config.Schema {
continue
}
}
columns, err := c.LoadsColumns(ctx, tableName)
if err != nil {
return nil, err
}
fqtn := fmt.Sprintf(`"%s"."%s"`, tableSchema, tableName)
// Get the total row count for this table
var rowCount int
countQuery := fmt.Sprintf("SELECT COUNT(*) FROM %s", fqtn)
err = c.db.Get(&rowCount, countQuery)
if err != nil {
return nil, xerrors.Errorf("unable to get row count for table %s: %w", tableName, err)
}
table := model.Table{
Name: fqtn,
Columns: columns,
RowCount: rowCount,
}
tables = append(tables, table)
}
return tables, nil
}
func (c Connector) Ping(ctx context.Context) error {
rows, err := c.db.QueryContext(ctx, "select 1+1")
if err != nil {
return xerrors.Errorf("unable to ping db: %w", err)
}
defer rows.Close()
for rows.Next() {
var res int
if err := rows.Scan(&res); err != nil {
return xerrors.Errorf("unable to scan ping result: %w", err)
}
}
if rows.Err() != nil {
return xerrors.Errorf("rows fetcher failed: %w", err)
}
return nil
}
func (c Connector) Query(ctx context.Context, endpoint model.Endpoint, params map[string]any) ([]map[string]any, error) {
processed, err := castx.ParamsE(endpoint, params)
if err != nil {
return nil, xerrors.Errorf("unable to process params: %w", err)
}
tx, err := c.db.BeginTxx(ctx, &sql.TxOptions{
ReadOnly: c.Config().Readonly(),
})
if err != nil {
return nil, xerrors.Errorf("BeginTx failed with error: %w", err)
}
defer tx.Commit()
rows, err := tx.NamedQuery(endpoint.Query, processed)
if err != nil {
return nil, xerrors.Errorf("unable to query db: %w", err)
}
defer rows.Close()
res := make([]map[string]any, 0)
for rows.Next() {
row := map[string]any{}
if err := rows.MapScan(row); err != nil {
return nil, xerrors.Errorf("unable to scan row: %w", err)
}
res = append(res, row)
}
return res, nil
}
func (c Connector) LoadsColumns(ctx context.Context, tableName string) ([]model.ColumnSchema, error) {
tx, err := c.db.BeginTxx(ctx, &sql.TxOptions{
ReadOnly: true,
})
if err != nil {
return nil, xerrors.Errorf("BeginTx failed with error: %w", err)
}
defer tx.Commit()
// Use the schema from config, default to 'public' if not specified
schema := "public"
if c.config.Schema != "" {
schema = c.config.Schema
}
rows, err := tx.QueryContext(
ctx,
`SELECT
c.column_name,
c.data_type,
c.is_nullable,
(SELECT true
FROM information_schema.table_constraints tc
JOIN information_schema.key_column_usage kcu
ON tc.constraint_name = kcu.constraint_name
AND tc.table_schema = kcu.table_schema
AND tc.table_name = kcu.table_name
WHERE tc.constraint_type = 'PRIMARY KEY'
AND tc.table_name = $1
AND tc.table_schema = $2
AND kcu.column_name = c.column_name) is not null as is_primary_key
FROM information_schema.columns c
WHERE c.table_name = $1
AND c.table_schema = $2`,
tableName, schema,
)
if err != nil {
return nil, xerrors.Errorf("unable to query columns: %w", err)
}
defer rows.Close()
var columns []model.ColumnSchema
for rows.Next() {
var name, dataType, isNullable string
var isPrimaryKey bool
if err := rows.Scan(&name, &dataType, &isNullable, &isPrimaryKey); err != nil {
return nil, xerrors.Errorf("unable to scan column info: %w", err)
}
columns = append(columns, model.ColumnSchema{
Name: name,
Type: c.GuessColumnType(dataType),
PrimaryKey: isPrimaryKey,
})
}
return columns, nil
}
// InferQuery implements the Connector interface
func (c *Connector) InferQuery(ctx context.Context, query string) ([]model.ColumnSchema, error) {
return c.base.InferResultColumns(ctx, query, c)
}