Support Postgres as configuration store #4551

Signed-off-by: akhilac1 <chetlapalle.akhila@gmail.com>
This commit is contained in:
akhilac1 2022-09-09 18:39:15 +05:30
parent ebaa1b5cc5
commit 269277bf6f
3 changed files with 389 additions and 0 deletions

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/*
Copyright 2021 The Dapr Authors
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
http://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.
*/
package postgres
import "time"
type metadata struct {
maxIdleTime time.Duration
connectionString string
configTable string
}

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/*
Copyright 2021 The Dapr Authors
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
http://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.
*/
package postgres
import (
"context"
"database/sql"
"encoding/json"
"fmt"
"os"
"reflect"
"strings"
"sync"
"time"
"github.com/dapr/components-contrib/configuration"
"github.com/dapr/kit/logger"
"github.com/google/uuid"
"github.com/jackc/pgconn"
"github.com/jackc/pgx/v4/pgxpool"
_ "github.com/jackc/pgx/v4/stdlib"
)
type PostgresConfigStore struct {
metadata metadata
pool *pgxpool.Pool
logger logger.Logger
subscribeStopChanMap sync.Map
}
const (
configtablekey = "table"
connMaxIdleTimeKey = "connMaxIdleTime"
connectionStringKey = "connectionString"
ErrorMissingTableName = "missing postgreSQL configuration table name"
InfoStartInit = "Initializing PostgreSQL state store"
ErrorMissingConnectionString = "missing postgreSQL connection string"
ErrorAlreadyInitialized = "PostgreSQL configuration store already initialized"
ErrorMissinMaxTimeout = "missing PostgreSQL maxTimeout setting in configuration"
QueryTableExists = "SELECT EXISTS (SELECT FROM pg_tables where tablename = $1)"
)
func NewPostgresConfigurationStore(logger logger.Logger) *PostgresConfigStore {
logger.Debug("Instantiating PostgreSQL configuration store")
return &PostgresConfigStore{
logger: logger,
}
}
func (p *PostgresConfigStore) Init(metadata configuration.Metadata) error {
p.logger.Debug(InfoStartInit)
if p.pool != nil {
return fmt.Errorf(ErrorAlreadyInitialized)
}
if m, err := parseMetadata(metadata); err != nil {
p.logger.Error(err)
return err
} else {
p.metadata = m
}
ctx := context.Background()
pool, err := Connect(ctx, p.metadata.connectionString)
if err != nil {
return err
}
p.pool = pool
pingErr := p.pool.Ping(ctx)
if pingErr != nil {
return pingErr
}
// check if table exists
exists := false
err = p.pool.QueryRow(ctx, QueryTableExists, p.metadata.configTable).Scan(&exists)
if err != nil {
return err
}
return nil
}
func (p *PostgresConfigStore) Get(ctx context.Context, req *configuration.GetRequest) (*configuration.GetResponse, error) {
query, err := buildQuery(req, p.metadata.configTable)
if err != nil {
p.logger.Error(err)
return nil, err
}
rows, err := p.pool.Query(ctx, query)
if err != nil {
// If no rows exist, return an empty response, otherwise return the error.
if err == sql.ErrNoRows {
return &configuration.GetResponse{}, nil
}
return nil, err
}
response := configuration.GetResponse{}
for i := 0; rows.Next(); i++ {
var item configuration.Item
var key string
var metadata []byte
var v = make(map[string]string)
if err := rows.Scan(key, &item.Value, &item.Version, &metadata); err != nil {
return nil, err
}
if err := json.Unmarshal(metadata, &v); err != nil {
return nil, err
}
item.Metadata = v
response.Items[key] = &item
}
return &response, nil
}
func (p *PostgresConfigStore) Subscribe(ctx context.Context, req *configuration.SubscribeRequest, handler configuration.UpdateHandler) (string, error) {
subscribeID := uuid.New().String()
key := "listen " + p.metadata.configTable
// subscribe to events raised on the configTable
if oldStopChan, ok := p.subscribeStopChanMap.Load(key); ok {
close(oldStopChan.(chan struct{}))
}
stop := make(chan struct{})
p.subscribeStopChanMap.Store(subscribeID, stop)
go p.doSubscribe(ctx, req, handler, key, subscribeID, stop)
return subscribeID, nil
}
func (p *PostgresConfigStore) Unsubscribe(ctx context.Context, req *configuration.UnsubscribeRequest) error {
if oldStopChan, ok := p.subscribeStopChanMap.Load(req.ID); ok {
p.subscribeStopChanMap.Delete(req.ID)
close(oldStopChan.(chan struct{}))
}
return nil
}
func (p *PostgresConfigStore) doSubscribe(ctx context.Context, req *configuration.SubscribeRequest, handler configuration.UpdateHandler, channel string, id string, stop chan struct{}) {
conn, err := p.pool.Acquire(ctx)
if err != nil {
fmt.Fprintln(os.Stderr, "Error acquiring connection:", err)
}
defer conn.Release()
_, err = conn.Exec(context.Background(), channel)
if err != nil {
p.logger.Errorf("Error listening to channel:", err)
return
}
for {
notification, err := conn.Conn().WaitForNotification(ctx)
if err != nil {
p.logger.Errorf("Error waiting for notification:", err)
return
}
p.handleSubscribedChange(ctx, handler, notification, id)
}
}
func (p *PostgresConfigStore) handleSubscribedChange(ctx context.Context, handler configuration.UpdateHandler, msg *pgconn.Notification, id string) {
defer func() {
if err := recover(); err != nil {
p.logger.Errorf("panic in handleSubscribedChange(method and recovered: %s", err)
}
}()
payload := make(map[string]interface{})
err := json.Unmarshal([]byte(msg.Payload), &payload)
if err != nil {
p.logger.Errorf("Error in UnMarshall: ", err)
return
}
var key, value, version string
m := make(map[string]string)
// trigger should encapsulate the row in "data" field in the notification
row := reflect.ValueOf(payload["data"])
if row.Kind() == reflect.Map {
for _, k := range row.MapKeys() {
v := row.MapIndex(k)
strKey := k.Interface().(string)
switch strings.ToLower(strKey) {
case "key":
key = v.Interface().(string)
case "value":
value = v.Interface().(string)
case "version":
version = v.Interface().(string)
case "metadata":
a := v.Interface().(map[string]interface{})
for k, v := range a {
m[k] = v.(string)
}
}
}
}
e := &configuration.UpdateEvent{
Items: map[string]*configuration.Item{
key: {
Value: value,
Version: version,
Metadata: m,
},
},
ID: id,
}
err = handler(ctx, e)
if err != nil {
p.logger.Errorf("fail to call handler to notify event for configuration update subscribe: %s", err)
}
}
func parseMetadata(cmetadata configuration.Metadata) (metadata, error) {
m := metadata{}
if val, ok := cmetadata.Properties[connectionStringKey]; ok && val != "" {
m.connectionString = val
} else {
return m, fmt.Errorf(ErrorMissingConnectionString)
}
if tbl, ok := cmetadata.Properties[configtablekey]; ok && tbl != "" {
m.configTable = tbl
} else {
return m, fmt.Errorf(ErrorMissingTableName)
}
// configure maxTimeout if provided
if mxTimeout, ok := cmetadata.Properties[connMaxIdleTimeKey]; ok && mxTimeout != "" {
if t, err := time.ParseDuration(mxTimeout); err == nil {
m.maxIdleTime = t
} else {
return m, fmt.Errorf(ErrorMissinMaxTimeout)
}
}
return m, nil
}
func Connect(ctx context.Context, conn string) (*pgxpool.Pool, error) {
pool, err := pgxpool.Connect(ctx, conn)
if err != nil {
return nil, fmt.Errorf("postgres configuration store connection error : %s", err)
}
pingErr := pool.Ping(context.Background())
if pingErr != nil {
return nil, fmt.Errorf("postgres configuration store ping error : %s", pingErr)
}
return pool, nil
}
func buildQuery(req *configuration.GetRequest, configTable string) (string, error) {
var query string
if len(req.Keys) == 0 {
query = "SELECT * FROM " + configTable
} else {
var queryBuilder strings.Builder
queryBuilder.WriteString("SELECT * FROM " + configTable + " WHERE KEY IN ('")
queryBuilder.WriteString(strings.Join(req.Keys, "','"))
queryBuilder.WriteString("')")
query = queryBuilder.String()
}
if len(req.Metadata) > 0 {
var s strings.Builder
i, j := len(req.Metadata), 0
s.WriteString(" AND ")
for k, v := range req.Metadata {
temp := k + "='" + v + "'"
s.WriteString(temp)
if j++; j < i {
s.WriteString(" AND ")
}
}
query += s.String()
}
return query, nil
}
func QueryRow(ctx context.Context, p *pgxpool.Pool, query string, tbl string) error {
exists := false
err := p.QueryRow(ctx, query, tbl).Scan(&exists)
if err != nil {
return fmt.Errorf("postgres configuration store query error : %s", err)
}
return nil
}

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/*
Copyright 2021 The Dapr Authors
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
http://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.
*/
package postgres
import (
"context"
"regexp"
"testing"
"github.com/dapr/components-contrib/configuration"
"github.com/pashagolub/pgxmock"
)
func TestPostgresbuildQuery(t *testing.T) {
g := &configuration.GetRequest{
Keys: []string{"someKey"},
Metadata: map[string]string{
"Version": "1.0",
},
}
query, err := buildQuery(g, "cfgtbl")
if err != nil {
t.Errorf("Error building query: %v ", err)
}
expected := "SELECT * FROM cfgtbl WHERE KEY IN ('someKey') AND Version='1.0'"
if query != expected {
t.Errorf("Did not get expected result. Got: '%v' , Expected: '%v'", query, expected)
}
}
func TestConnectAndQuery(t *testing.T) {
m := metadata{
connectionString: "mockConnectionString",
configTable: "mockConfigTable",
}
mock, err := pgxmock.NewPool()
if err != nil {
t.Fatalf("an error '%s' was not expected when opening a stub database connection", err)
}
defer mock.Close()
query := "SELECT EXISTS (SELECT FROM pg_tables where tablename = '" + m.configTable + "'"
mock.ExpectQuery(regexp.QuoteMeta(query)).
WillReturnRows(pgxmock.NewRows(
[]string{"exists"}).
AddRow(string("t")),
)
rows := mock.QueryRow(context.Background(), query)
var id string
err = rows.Scan(&id)
if err != nil {
t.Error(err)
}
if err := mock.ExpectationsWereMet(); err != nil {
t.Errorf("there were unfulfilled expectations: %s", err)
}
}