✨ feat: added postgres service interface and handler #1

Author: pnguyen215

postgresconn/postgresconn.go

@@ -64,10 +64,6 @@ func NewClient(config postgres.PostgresConfig) (*sqlx.DB, dbx.Dbx) {
 }
 
 func GetPostgresPIDConn(db *sqlx.DB) (int, error) {
-	var pid int
-	err := db.QueryRow("SELECT pg_backend_pid() AS pid").Scan(&pid)
-	if err != nil {
-		return 0, err
-	}
-	return pid, nil
+	s := NewPostgresService(db)
+	return s.GetPIDConn()
 }

postgresconn/postgresconn_model.go

@@ -1 +1,8 @@
 package postgresconn
+
+type PostgresFunctionDetail struct {
+	RoutineName   string `db:"routine_name" json:"routine_name"`
+	DataType      string `db:"data_type" json:"data_type"`
+	ParameterName string `db:"parameter_name" json:"parameter_name"`
+	ParameterMode string `db:"parameter_mode" json:"parameter_mode"`
+}

postgresconn/postgresconn_service.go

@@ -0,0 +1,153 @@
+package postgresconn
+
+import (
+	"strings"
+
+	"github.com/jmoiron/sqlx"
+
+	_ "github.com/lib/pq"
+)
+
+type PostgresService interface {
+	GetPIDConn() (int, error)
+	Database() string
+	GetAllTables() ([]string, error)
+	GetAllFunctions() ([]string, error)
+	GetAllProcedures() ([]string, error)
+	GetFunctionDetails(function string) ([]PostgresFunctionDetail, error)
+	GetFunctionReturnType(function string) (string, error)
+	BuildFunction(function string) (string, error)
+	ShowFunctionContent(function string) (string, error)
+	ShowProcedureContent(procedure string) (string, error)
+}
+
+type postgresServiceImpl struct {
+	dbConn *sqlx.DB
+}
+
+func NewPostgresService(dbConn *sqlx.DB) PostgresService {
+	p := &postgresServiceImpl{
+		dbConn: dbConn,
+	}
+	return p
+}
+
+func (p *postgresServiceImpl) GetPIDConn() (int, error) {
+	var pid int
+	err := p.dbConn.QueryRow("SELECT pg_backend_pid() AS pid").Scan(&pid)
+	if err != nil {
+		return 0, err
+	}
+	return pid, nil
+}
+
+func (p *postgresServiceImpl) GetAllTables() ([]string, error) {
+	var tableNames []string
+	err := p.dbConn.Select(&tableNames, "SELECT table_name FROM information_schema.tables WHERE table_schema='public' AND table_type='BASE TABLE'")
+	if err != nil {
+		return nil, err
+	}
+	return tableNames, nil
+}
+
+func (p *postgresServiceImpl) GetAllFunctions() ([]string, error) {
+	var functions []string
+	err := p.dbConn.Select(&functions, "SELECT routine_name FROM information_schema.routines WHERE routine_catalog = $1 AND routine_schema = 'public' AND routine_type = 'FUNCTION'", p.Database())
+	if err != nil {
+		return nil, err
+	}
+	return functions, nil
+}
+
+func (p *postgresServiceImpl) Database() string {
+	var database string
+	err := p.dbConn.Get(&database, "SELECT current_database()")
+	if err != nil {
+		panic(err)
+	}
+	return database
+}
+
+func (p *postgresServiceImpl) GetAllProcedures() ([]string, error) {
+	var procedures []string
+	err := p.dbConn.Select(&procedures, "SELECT routine_name FROM information_schema.routines WHERE routine_catalog = $1 AND routine_schema = 'public' AND routine_type = 'PROCEDURE'", p.Database())
+	if err != nil {
+		return nil, err
+	}
+	return procedures, nil
+}
+
+func (p *postgresServiceImpl) GetFunctionDetails(function string) ([]PostgresFunctionDetail, error) {
+	var functionDetails []PostgresFunctionDetail
+	err := p.dbConn.Select(&functionDetails, `
+	SELECT 
+		r.routine_name, 
+		p.data_type, 
+		p.parameter_name, 
+		p.parameter_mode 
+	FROM information_schema.routines r 
+	JOIN information_schema.parameters p 
+		ON r.specific_name = p.specific_name 
+	WHERE r.routine_catalog = $1 
+		AND r.routine_schema = 'public' 
+		AND r.routine_name = $2
+        `, p.Database(), function)
+	if err != nil {
+		return nil, err
+	}
+	return functionDetails, nil
+}
+
+func (p *postgresServiceImpl) GetFunctionReturnType(function string) (string, error) {
+	var returnType string
+	err := p.dbConn.QueryRow("SELECT pg_get_function_result(oid) FROM pg_proc WHERE proname = $1", function).Scan(&returnType)
+	if err != nil {
+		return "", err
+	}
+	return returnType, nil
+}
+
+func (p *postgresServiceImpl) BuildFunction(function string) (string, error) {
+	functionDetails, err := p.GetFunctionDetails(function)
+	if err != nil {
+		return "", err
+	}
+	returnType, err := p.GetFunctionReturnType(function)
+	if err != nil {
+		return "", err
+	}
+	var builder strings.Builder
+	builder.WriteString("CREATE OR REPLACE FUNCTION " + function + "(")
+	for i, detail := range functionDetails {
+		if i > 0 {
+			builder.WriteString(", ")
+		}
+		builder.WriteString(detail.ParameterName + " " + detail.DataType)
+		if detail.ParameterMode != "IN" {
+			builder.WriteString(" " + detail.ParameterMode)
+		}
+	}
+	builder.WriteString(") RETURNS " + returnType + " AS $$\n")
+	builder.WriteString("BEGIN\n\n")
+	builder.WriteString("\n")
+	builder.WriteString("\nEND;\n$$ LANGUAGE plpgsql;")
+	return builder.String(), nil
+}
+
+func (ps *postgresServiceImpl) ShowFunctionContent(function string) (string, error) {
+	var functionContent string
+	err := ps.dbConn.QueryRow("SELECT pg_get_functiondef($1::regproc)", function).Scan(&functionContent)
+	if err != nil {
+		return "", err
+	}
+	return functionContent, nil
+}
+
+func (p *postgresServiceImpl) ShowProcedureContent(procedure string) (string, error) {
+	var procedureContent string
+	err := p.dbConn.QueryRow("SELECT pg_get_functiondef($1::regproc)", procedure).Scan(&procedureContent)
+	if err != nil {
+		return "", err
+	}
+	return procedureContent, nil
+}