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package procapi
import (
"context"
"fmt"
"net/http"
"reflect"
"strings"
"sync"
"github.com/jackc/pgx/v4"
"github.com/go-logr/logr"
)
// codebeat:disable[TOO_MANY_IVARS]
// Config defines local application flags
type Config struct {
DSN string `long:"dsn" default:"postgres://?sslmode=disable" description:"Database connect string"`
Driver string `long:"driver" default:"postgres" description:"Database driver"`
InDefFunc string `long:"indef" default:"func_args" description:"Argument definition function"`
OutDefFunc string `long:"outdef" default:"func_result" description:"Result row definition function"`
IndexFunc string `long:"index" default:"index" description:"Available functions list"`
FuncSchema string `long:"schema" default:"rpc" description:"Definition functions schema"`
ArgSyntax string `long:"arg_syntax" default:":=" description:"Default named args syntax (:= or =>)"`
ArgTrimPrefix string `long:"arg_prefix" default:"a_" description:"Trim prefix from arg name"`
NameSpaces *[]string `long:"nsp" description:"Proc namespace(s)"`
// TODO: Lim*
// LimArg - если у ф-и нет этого аргумента, добавить в запрос `LIMIT LimDefault`
// LimDefault - лимит строк по умолчанию
}
// InDef holds function argument attributes
type InDef struct {
Name string `db:"arg"`
Type string `db:"type"`
Required bool `db:"required"` // TODO: is_required
Default *string `db:"def_val" json:",omitempty"`
Anno *string `db:"anno" json:",omitempty"`
// Check string `json:"check,omitempty" sql:"-"` // validate argument
}
// OutDef holds function result attributes
type OutDef struct {
Name string `db:"arg"`
Type string `db:"type"`
Anno *string `db:"anno" json:",omitempty"`
}
// Method holds method attributes
type Method struct {
Name string `db:"code"`
Class string `db:"nspname"`
Func string `db:"proname"`
Anno string `db:"anno"`
IsRO bool `db:"is_ro"`
IsSet bool `db:"is_set"`
IsStruct bool `db:"is_struct"`
Sample *string `db:"sample" json:",omitempty"`
Result *string `db:"result" json:",omitempty"`
In map[string]InDef //`json:",omitempty"`
Out []OutDef //`json:",omitempty"`
}
// Service holds API service methods
type Service struct {
dbh *pgx.Conn
config Config
log logr.Logger
methods map[string]Method
mx sync.RWMutex
typeM Marshaller
schemaSuffix string
}
// codebeat:enable[TOO_MANY_IVARS]
// Marshaller holds methods for database values marshalling
type Marshaller interface {
Marshal(typ string, v interface{}) (interface{}, error)
Unmarshal(typ string, data interface{}) (rv interface{}, err error)
}
//Functional options
//https://github.com/tmrts/go-patterns/blob/master/idiom/functional-options.md
// Option is a functional options return type
type Option func(*Service)
// Marshall allows to change default marshaller
func Marshall(m Marshaller) Option {
return func(srv *Service) {
srv.typeM = m
}
}
// New returns procapi service
func New(cfg Config, log logr.Logger, dbh *pgx.Conn, options ...Option) *Service {
srv := &Service{
log: log, config: cfg, dbh: dbh,
}
for _, option := range options {
option(srv)
}
if srv.typeM == nil {
srv.typeM = &PGType{}
}
return srv
}
// Method returns method by name
func (srv *Service) Method(name string) (Method, bool) {
srv.mx.RLock()
defer srv.mx.RUnlock()
m, ok := srv.methods[name]
return m, ok
}
// LoadMethodsTx load methods within given transaction for nsp if given, all of methods otherwise
func (srv *Service) LoadMethodsTx(tx pgx.Tx) error {
rv, err := srv.FetchMethods(tx, srv.config.NameSpaces)
if err != nil {
return err
}
srv.mx.Lock()
srv.methods = rv
srv.mx.Unlock()
return nil
}
// FetchMethods fetches from DB methods definition for given namespaces
func (srv *Service) FetchMethods(tx pgx.Tx, nsp *[]string) (map[string]Method, error) {
const SQL = "select * from %s.%s(%s)"
schema := srv.config.FuncSchema
if srv.schemaSuffix != "" {
schema += "_" + srv.schemaSuffix
}
ctx := context.Background()
rows, err := tx.Query(ctx, fmt.Sprintf(SQL, schema, srv.config.IndexFunc, positionalArgs(nsp)), nsp)
if err != nil {
return nil, err
}
defer rows.Close()
rvTemp := []Method{}
for rows.Next() {
r := Method{}
err := ScanStruct(rows, &r)
if err != nil {
return nil, err
}
rvTemp = append(rvTemp, r)
}
rv := map[string]Method{}
for _, v := range rvTemp {
k := v.Name
rows, err := tx.Query(ctx, fmt.Sprintf(SQL, schema, srv.config.InDefFunc, positionalArgs(k)), k)
if err != nil {
return nil, err
}
defer rows.Close()
inArgs := map[string]InDef{}
for rows.Next() {
r := InDef{}
err := ScanStruct(rows, &r)
if err != nil {
return nil, err
}
inArgs[strings.TrimPrefix(r.Name, srv.config.ArgTrimPrefix)] = r
}
v.In = inArgs
rows, err = tx.Query(ctx, fmt.Sprintf(SQL, schema, srv.config.OutDefFunc, positionalArgs(k)), k)
if err != nil {
return nil, err
}
defer rows.Close()
for rows.Next() {
r := OutDef{}
err := ScanStruct(rows, &r)
if err != nil {
return nil, err
}
v.Out = append(v.Out, r)
}
rv[k] = v
}
return rv, nil
}
// Call calls postgresql stored function
func (srv *Service) Call(
r *http.Request, // TODO: interface to session & request data
method string,
args map[string]interface{},
) (interface{}, error) {
srv.mx.RLock()
dbh := srv.dbh
srv.mx.RUnlock()
ctx := context.Background()
tx, err := dbh.Begin(ctx)
if err != nil {
return nil, err
}
var rv interface{}
rv, err = srv.CallTx(tx, method, args)
if err != nil { // TODO: or Method.IsRo
tx.Rollback(ctx)
} else {
err = tx.Commit(ctx)
}
return rv, err
}
// CallTx calls postgresql stored function within given transaction
func (srv *Service) CallTx( //r *http.Request,
tx pgx.Tx,
method string,
args map[string]interface{},
) (interface{}, error) {
// Check for Marshaller is set
if srv.typeM == nil {
return nil, &callError{code: errNilMarshaller}
}
// Lookup method.
methodSpec, ok := srv.Method(method)
if !ok {
return nil, (&callError{code: errNotFound}).addContext("name", method)
}
var missedArgs []string
var inAssigns []string
var inVars []interface{}
var err error
if methodSpec.In != nil {
missedArgs, inAssigns, inVars, err = srv.namedArgs(methodSpec.In, args)
}
if err != nil {
return nil, err
}
if len(missedArgs) > 0 {
return nil, (&callError{code: errArgsMissed}).addContext("args", missedArgs)
}
ctx := context.Background()
if methodSpec.Result != nil && *methodSpec.Result == "void" {
// no data returned
sql := fmt.Sprintf("SELECT %s.%s(%s)",
methodSpec.Class,
methodSpec.Func,
strings.Join(inAssigns, ", "),
)
qr, err := tx.Exec(ctx, sql, inVars...)
ctra := qr.RowsAffected()
srv.log.Debugf("Rows affected: %d", ctra) // TODO: Header.Add ?
return nil, err
}
var outCols []string
if methodSpec.Out != nil {
for _, v := range methodSpec.Out {
outCols = append(outCols, v.Name)
}
}
from := ""
if len(outCols) > 0 {
from = " from "
}
sql := fmt.Sprintf("select %s%s%s.%s(%s)",
strings.Join(outCols, ", "),
from,
methodSpec.Class,
methodSpec.Func,
strings.Join(inAssigns, ", "),
)
srv.log.Debugf("sql: %s, args: %v\n", sql, inVars)
// fmt.Printf(">>> row------------------: %+v %v\n", sql, inVars)
rows, err := tx.Query(ctx, sql, inVars...)
if err != nil {
return nil, err
}
if rows.Err() != nil {
return nil, rows.Err()
}
defer rows.Close()
return fetch(methodSpec, srv.typeM, rows)
}
func fetch(methodSpec Method, mars Marshaller, rows pgx.Rows) (interface{}, error) {
var rv []interface{}
var err error
for rows.Next() {
var r interface{}
if methodSpec.IsStruct {
m := map[string]interface{}{}
err = ScanMap(rows, &m)
if err != nil {
return nil, err
}
for _, c := range methodSpec.Out {
if m[c.Name] == nil {
continue
}
out, err := mars.Unmarshal(c.Type, m[c.Name])
if err != nil {
return nil, err
}
m[c.Name] = out
}
r = m
} else {
// get 1st column only
var rr []interface{}
rr, err = rows.Values()
if err != nil {
return nil, err
}
r = rr[0]
}
rv = append(rv, r)
}
if !methodSpec.IsSet {
if len(rv) != 1 {
return nil, &callError{code: errNotSingleRV}
}
rv0 := rv[0]
return &rv0, nil // might be null
}
return rv, nil
}
// namedArgs returns data for building proc call with named args
func (srv *Service) namedArgs(
inDef map[string]InDef,
args map[string]interface{},
) (
missedArgs []string,
inAssigns []string,
inVars []interface{},
err error,
) {
log := srv.log
log.Debugf("IN args: %+v", inDef)
for k, v := range inDef {
a, ok := args[k]
if !ok {
if v.Required {
missedArgs = append(missedArgs, k)
} else {
log.Debugf("Skip missed value of %s", k)
}
continue
}
if reflect.ValueOf(a).Kind() == reflect.Ptr {
if reflect.ValueOf(a).IsNil() {
if v.Required {
missedArgs = append(missedArgs, k)
continue
} else {
log.Debugf("Use NULL for empty ref of %s", k)
}
} else {
a = reflect.ValueOf(a).Elem().Interface() // dereference ptr
}
}
inAssigns = append(inAssigns, fmt.Sprintf("%s %s $%d", v.Name, srv.config.ArgSyntax, len(inAssigns)+1))
out, e := srv.typeM.Marshal(v.Type, a)
if e != nil {
err = (&callError{code: errArgCast}).
addContext("arg", v.Name).
addContext("type", v.Type).
addContext("val", a).
addContext("err", e)
return
}
a = out
inVars = append(inVars, a)
log.Debugf("Use: %s (%+v)", k, a)
}
return
}
// positionalArgs returns string with function args placeholders
func positionalArgs(args ...interface{}) string {
inAssigns := make([]string, len(args))
for i := range args {
inAssigns[i] = fmt.Sprintf("$%d", i+1)
}
return strings.Join(inAssigns, ", ")
}