/
postgres.go
671 lines (574 loc) · 15.5 KB
/
postgres.go
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// Copyright 2020 Asim Aslam
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// Original source: github.com/micro/go-plugins/v3/store/cockroach/cockroach.go
// Package postgres implements the postgres store
package postgres
import (
"database/sql"
"database/sql/driver"
"fmt"
"net"
"net/url"
"regexp"
"strings"
"sync"
"syscall"
"time"
"github.com/lib/pq"
"github.com/micro/micro/v3/service/logger"
"github.com/micro/micro/v3/service/store"
"github.com/pkg/errors"
)
// DefaultDatabase is the namespace that the sql store
// will use if no namespace is provided.
var (
DefaultDatabase = "micro"
DefaultTable = "micro"
ErrNoConnection = errors.New("Database connection not initialised")
)
var (
re = regexp.MustCompile("[^a-zA-Z0-9]+")
// alternative ordering
orderAsc = "ORDER BY key ASC"
orderDesc = "ORDER BY key DESC"
// the sql statements we prepare and use
statements = map[string]string{
"list": "SELECT key, value, metadata, expiry FROM %s.%s WHERE key LIKE $1 ORDER BY key ASC LIMIT $2 OFFSET $3;",
"read": "SELECT key, value, metadata, expiry FROM %s.%s WHERE key = $1;",
"readMany": "SELECT key, value, metadata, expiry FROM %s.%s WHERE key LIKE $1 ORDER BY key ASC;",
"readOffset": "SELECT key, value, metadata, expiry FROM %s.%s WHERE key LIKE $1 ORDER BY key ASC LIMIT $2 OFFSET $3;",
"write": "INSERT INTO %s.%s(key, value, metadata, expiry) VALUES ($1, $2::bytea, $3, $4) ON CONFLICT (key) DO UPDATE SET value = EXCLUDED.value, metadata = EXCLUDED.metadata, expiry = EXCLUDED.expiry;",
"delete": "DELETE FROM %s.%s WHERE key = $1;",
"deleteExpired": "DELETE FROM %s.%s WHERE expiry < now();",
"showTables": "SELECT schemaname, tablename FROM pg_catalog.pg_tables WHERE schemaname != 'pg_catalog' AND schemaname != 'information_schema';",
}
)
type sqlStore struct {
options store.Options
dbConn *sql.DB
sync.RWMutex
// known databases
databases map[string]bool
}
func (s *sqlStore) getDB(database, table string) (string, string) {
if len(database) == 0 {
if len(s.options.Database) > 0 {
database = s.options.Database
} else {
database = DefaultDatabase
}
}
if len(table) == 0 {
if len(s.options.Table) > 0 {
table = s.options.Table
} else {
table = DefaultTable
}
}
// store.namespace must only contain letters, numbers and underscores
database = re.ReplaceAllString(database, "_")
table = re.ReplaceAllString(table, "_")
return database, table
}
// createDB ensures that the DB and table have been created. It's used for lazy initialisation
// and will record which tables have been created to reduce calls to the DB
func (s *sqlStore) createDB(database, table string) error {
database, table = s.getDB(database, table)
s.Lock()
defer s.Unlock()
if _, ok := s.databases[database+":"+table]; ok {
return nil
}
if err := s.initDB(database, table); err != nil {
return err
}
s.databases[database+":"+table] = true
return nil
}
// db returns a valid connection to the DB
func (s *sqlStore) db() (*sql.DB, error) {
if s.dbConn == nil {
return nil, ErrNoConnection
}
if err := s.dbConn.Ping(); err != nil {
if !isBadConnError(err) {
return nil, err
}
logger.Errorf("Error with DB connection, will reconfigure: %s", err)
if err := s.configure(); err != nil {
logger.Errorf("Error while reconfiguring client: %s", err)
return nil, err
}
}
return s.dbConn, nil
}
// isBadConnError returns true if the error is related to having a bad connection such that you need to reconnect
func isBadConnError(err error) bool {
if err == nil {
return false
}
if err == driver.ErrBadConn {
return true
}
// heavy handed crude check for "connection reset by peer"
if strings.Contains(err.Error(), syscall.ECONNRESET.Error()) {
return true
}
// otherwise iterate through the error types
switch t := err.(type) {
case syscall.Errno:
return t == syscall.ECONNRESET || t == syscall.ECONNABORTED || t == syscall.ECONNREFUSED
case *net.OpError:
return !t.Temporary()
case net.Error:
return !t.Temporary()
}
return false
}
func (s *sqlStore) initDB(database, table string) error {
db, err := s.db()
if err != nil {
return err
}
// Create the namespace's database
_, err = db.Exec(fmt.Sprintf("CREATE DATABASE %s;", database))
if err != nil && !strings.Contains(err.Error(), "already exists") {
return err
}
var version string
if err = db.QueryRow("select version()").Scan(&version); err == nil {
if strings.Contains(version, "PostgreSQL") {
_, err = db.Exec(fmt.Sprintf("CREATE SCHEMA IF NOT EXISTS %s;", database))
if err != nil {
return err
}
}
}
// Create a table for the namespace's prefix
_, err = db.Exec(fmt.Sprintf(`CREATE TABLE IF NOT EXISTS %s.%s
(
key text NOT NULL,
value bytea,
metadata JSONB,
expiry timestamp with time zone,
CONSTRAINT %s_pkey PRIMARY KEY (key)
);`, database, table, table))
if err != nil {
return errors.Wrap(err, "Couldn't create table")
}
// Create Index
_, err = db.Exec(fmt.Sprintf(`CREATE INDEX IF NOT EXISTS "%s" ON %s.%s USING btree ("key");`, "key_index_"+table, database, table))
if err != nil {
return err
}
// Create Metadata Index
_, err = db.Exec(fmt.Sprintf(`CREATE INDEX IF NOT EXISTS "%s" ON %s.%s USING GIN ("metadata");`, "metadata_index_"+table, database, table))
if err != nil {
return err
}
return nil
}
func (s *sqlStore) configure() error {
if len(s.options.Nodes) == 0 {
s.options.Nodes = []string{"postgresql://root@localhost:26257?sslmode=disable"}
}
source := s.options.Nodes[0]
// check if it is a standard connection string eg: host=%s port=%d user=%s password=%s dbname=%s sslmode=disable
// if err is nil which means it would be a URL like postgre://xxxx?yy=zz
_, err := url.Parse(source)
if err != nil {
if !strings.Contains(source, " ") {
source = fmt.Sprintf("host=%s", source)
}
}
// create source from first node
db, err := sql.Open("postgres", source)
if err != nil {
return err
}
if err := db.Ping(); err != nil {
return err
}
if s.dbConn != nil {
s.dbConn.Close()
}
// save the values
s.dbConn = db
// get DB
database, table := s.getDB(s.options.Database, s.options.Table)
// initialise the database
return s.initDB(database, table)
}
func (s *sqlStore) prepare(database, table, query string, order store.Order) (*sql.Stmt, error) {
st, ok := statements[query]
if !ok {
return nil, errors.New("unsupported statement")
}
// set the order in the statement
// TODO: replace with better sql compositon
if order == store.OrderDesc {
st = strings.Replace(st, orderAsc, orderDesc, 1)
}
// get DB
database, table = s.getDB(database, table)
q := fmt.Sprintf(st, database, table)
db, err := s.db()
if err != nil {
return nil, err
}
stmt, err := db.Prepare(q)
if err != nil {
return nil, err
}
return stmt, nil
}
func (s *sqlStore) Close() error {
if s.dbConn != nil {
return s.dbConn.Close()
}
return nil
}
func (s *sqlStore) Init(opts ...store.Option) error {
for _, o := range opts {
o(&s.options)
}
// reconfigure
return s.configure()
}
// List all the known records
func (s *sqlStore) List(opts ...store.ListOption) ([]string, error) {
options := store.ListOptions{
Order: store.OrderAsc,
}
for _, o := range opts {
o(&options)
}
// create the db if not exists
if err := s.createDB(options.Database, options.Table); err != nil {
return nil, err
}
limit := sql.NullInt32{}
offset := 0
pattern := "%"
if options.Prefix != "" || options.Suffix != "" {
if options.Prefix != "" {
pattern = options.Prefix + pattern
}
if options.Suffix != "" {
pattern = pattern + options.Suffix
}
}
if options.Offset > 0 {
offset = int(options.Offset)
}
if options.Limit > 0 {
limit = sql.NullInt32{Int32: int32(options.Limit), Valid: true}
}
st, err := s.prepare(options.Database, options.Table, "list", options.Order)
if err != nil {
return nil, err
}
defer st.Close()
rows, err := st.Query(pattern, limit, offset)
if err != nil {
if err == sql.ErrNoRows {
return nil, nil
}
return nil, err
}
defer rows.Close()
var keys []string
records, err := s.rowsToRecords(rows)
if err != nil {
return nil, err
}
for _, k := range records {
keys = append(keys, k.Key)
}
rowErr := rows.Close()
if rowErr != nil {
// transaction rollback or something
return keys, rowErr
}
if err := rows.Err(); err != nil {
return keys, err
}
return keys, nil
}
// rowToRecord converts from sql.Row to a store.Record. If the record has expired it will issue a delete in a separate goroutine
func (s *sqlStore) rowToRecord(row *sql.Row) (*store.Record, error) {
var timehelper pq.NullTime
record := &store.Record{}
metadata := make(Metadata)
if err := row.Scan(&record.Key, &record.Value, &metadata, &timehelper); err != nil {
if err == sql.ErrNoRows {
return record, store.ErrNotFound
}
return nil, err
}
// set the metadata
record.Metadata = toMetadata(&metadata)
if timehelper.Valid {
if timehelper.Time.Before(time.Now()) {
// record has expired
go s.Delete(record.Key)
return nil, store.ErrNotFound
}
record.Expiry = time.Until(timehelper.Time)
}
return record, nil
}
// rowsToRecords converts from sql.Rows to []*store.Record. If a record has expired it will issue a delete in a separate goroutine
func (s *sqlStore) rowsToRecords(rows *sql.Rows) ([]*store.Record, error) {
var records []*store.Record
var timehelper pq.NullTime
for rows.Next() {
record := &store.Record{}
metadata := make(Metadata)
if err := rows.Scan(&record.Key, &record.Value, &metadata, &timehelper); err != nil {
return records, err
}
// set the metadata
record.Metadata = toMetadata(&metadata)
if timehelper.Valid {
if timehelper.Time.Before(time.Now()) {
// record has expired
go s.Delete(record.Key)
} else {
record.Expiry = time.Until(timehelper.Time)
records = append(records, record)
}
} else {
records = append(records, record)
}
}
return records, nil
}
// Read a single key
func (s *sqlStore) Read(key string, opts ...store.ReadOption) ([]*store.Record, error) {
options := store.ReadOptions{
Order: store.OrderAsc,
}
for _, o := range opts {
o(&options)
}
// create the db if not exists
if err := s.createDB(options.Database, options.Table); err != nil {
return nil, err
}
if options.Prefix || options.Suffix {
return s.read(key, options)
}
st, err := s.prepare(options.Database, options.Table, "read", options.Order)
if err != nil {
return nil, err
}
defer st.Close()
row := st.QueryRow(key)
record, err := s.rowToRecord(row)
if err != nil {
return nil, err
}
var records []*store.Record
return append(records, record), nil
}
// Read Many records
func (s *sqlStore) read(key string, options store.ReadOptions) ([]*store.Record, error) {
pattern := "%"
if options.Prefix {
pattern = key + pattern
}
if options.Suffix {
pattern = pattern + key
}
var rows *sql.Rows
var st *sql.Stmt
var err error
if options.Limit != 0 {
st, err = s.prepare(options.Database, options.Table, "readOffset", options.Order)
if err != nil {
return nil, err
}
defer st.Close()
rows, err = st.Query(pattern, options.Limit, options.Offset)
} else {
st, err = s.prepare(options.Database, options.Table, "readMany", options.Order)
if err != nil {
return nil, err
}
defer st.Close()
rows, err = st.Query(pattern)
}
if err != nil {
if err == sql.ErrNoRows {
return []*store.Record{}, nil
}
return []*store.Record{}, errors.Wrap(err, "sqlStore.read failed")
}
defer rows.Close()
records, err := s.rowsToRecords(rows)
if err != nil {
return nil, err
}
rowErr := rows.Close()
if rowErr != nil {
// transaction rollback or something
return records, rowErr
}
if err := rows.Err(); err != nil {
return records, err
}
return records, nil
}
// Write records
func (s *sqlStore) Write(r *store.Record, opts ...store.WriteOption) error {
var options store.WriteOptions
for _, o := range opts {
o(&options)
}
// create the db if not exists
if err := s.createDB(options.Database, options.Table); err != nil {
return err
}
st, err := s.prepare(options.Database, options.Table, "write", store.OrderAsc)
if err != nil {
return err
}
defer st.Close()
metadata := make(Metadata)
for k, v := range r.Metadata {
metadata[k] = v
}
var expiry time.Time
if r.Expiry != 0 {
expiry = time.Now().Add(r.Expiry)
}
if expiry.IsZero() {
_, err = st.Exec(r.Key, r.Value, metadata, nil)
} else {
_, err = st.Exec(r.Key, r.Value, metadata, expiry)
}
if err != nil {
return errors.Wrap(err, "Couldn't insert record "+r.Key)
}
return nil
}
// Delete records with keys
func (s *sqlStore) Delete(key string, opts ...store.DeleteOption) error {
var options store.DeleteOptions
for _, o := range opts {
o(&options)
}
// create the db if not exists
if err := s.createDB(options.Database, options.Table); err != nil {
return err
}
st, err := s.prepare(options.Database, options.Table, "delete", store.OrderAsc)
if err != nil {
return err
}
defer st.Close()
result, err := st.Exec(key)
if err != nil {
return err
}
_, err = result.RowsAffected()
if err != nil {
return err
}
return nil
}
func (s *sqlStore) Options() store.Options {
return s.options
}
func (s *sqlStore) String() string {
return "cockroach"
}
// NewStore returns a new micro Store backed by sql
func NewStore(opts ...store.Option) store.Store {
options := store.Options{
Database: DefaultDatabase,
Table: DefaultTable,
}
for _, o := range opts {
o(&options)
}
// new store
s := new(sqlStore)
// set the options
s.options = options
// mark known databases
s.databases = make(map[string]bool)
// best-effort configure the store
if err := s.configure(); err != nil {
if logger.V(logger.ErrorLevel, logger.DefaultLogger) {
logger.Error("Error configuring store ", err)
}
}
go s.expiryLoop()
// return store
return s
}
func (s *sqlStore) expiryLoop() {
for {
s.expireRows()
time.Sleep(1 * time.Hour)
}
}
func (s *sqlStore) expireRows() error {
db, err := s.db()
if err != nil {
logger.Errorf("Error getting DB connection %s", err)
return err
}
stmt, err := db.Prepare(statements["showTables"])
if err != nil {
logger.Errorf("Error prepping show tables query %s", err)
return err
}
defer stmt.Close()
rows, err := stmt.Query()
if err != nil {
logger.Errorf("Error running show tables query %s", err)
return err
}
defer rows.Close()
for rows.Next() {
var schemaName, tableName string
if err := rows.Scan(&schemaName, &tableName); err != nil {
logger.Errorf("Error parsing result %s", err)
return err
}
db, err = s.db()
if err != nil {
logger.Errorf("Error prepping delete expired query %s", err)
return err
}
delStmt, err := db.Prepare(fmt.Sprintf(statements["deleteExpired"], schemaName, tableName))
if err != nil {
logger.Errorf("Error prepping delete expired query %s", err)
return err
}
defer delStmt.Close()
res, err := delStmt.Exec()
if err != nil {
logger.Errorf("Error cleaning up %s", err)
return err
}
r, _ := res.RowsAffected()
logger.Infof("Cleaning up %s %s: %d rows deleted", schemaName, tableName, r)
}
return nil
}