/
postgres.go
465 lines (387 loc) · 12.9 KB
/
postgres.go
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package postgres
import (
"context"
dbsql "database/sql"
"errors"
"fmt"
"time"
"github.com/IBM/pgxpoolprometheus"
sq "github.com/Masterminds/squirrel"
"github.com/jackc/pgconn"
"github.com/jackc/pgx/v4"
"github.com/jackc/pgx/v4/pgxpool"
"github.com/jackc/pgx/v4/stdlib"
"github.com/ngrok/sqlmw"
"github.com/prometheus/client_golang/prometheus"
"go.opentelemetry.io/otel"
"golang.org/x/sync/errgroup"
"github.com/authzed/spicedb/internal/datastore/common"
"github.com/authzed/spicedb/internal/datastore/common/revisions"
pgxcommon "github.com/authzed/spicedb/internal/datastore/postgres/common"
"github.com/authzed/spicedb/internal/datastore/postgres/migrations"
"github.com/authzed/spicedb/internal/datastore/proxy"
log "github.com/authzed/spicedb/internal/logging"
"github.com/authzed/spicedb/pkg/datastore"
)
func init() {
datastore.Engines = append(datastore.Engines, Engine)
}
const (
Engine = "postgres"
tableNamespace = "namespace_config"
tableTransaction = "relation_tuple_transaction"
tableTuple = "relation_tuple"
tableCaveat = "caveat"
colXID = "xid"
colTimestamp = "timestamp"
colNamespace = "namespace"
colConfig = "serialized_config"
colCreatedXid = "created_xid"
colDeletedXid = "deleted_xid"
colSnapshot = "snapshot"
colObjectID = "object_id"
colRelation = "relation"
colUsersetNamespace = "userset_namespace"
colUsersetObjectID = "userset_object_id"
colUsersetRelation = "userset_relation"
colCaveatName = "name"
colCaveatDefinition = "definition"
colCaveatContextName = "caveat_name"
colCaveatContext = "caveat_context"
errUnableToInstantiate = "unable to instantiate datastore: %w"
// The parameters to this format string are:
// 1: the created_xid or deleted_xid column name
// 2: the transaction table's snapshot column name
// 3: the transaction table name
// 4: the transaction table's xid column name
// 5: a squirrel library placeholder string, i.e. `?`
snapshotAlive = "pg_visible_in_snapshot(%[1]s, (SELECT %[2]s FROM %[3]s WHERE %[4]s = %[5]s)) = %[5]s"
// This is the largest positive integer possible in postgresql
liveDeletedTxnID = uint64(9223372036854775807)
tracingDriverName = "postgres-tracing"
batchDeleteSize = 1000
pgSerializationFailure = "40001"
pgUniqueConstraintViolation = "23505"
livingTupleConstraint = "uq_relation_tuple_living_xid"
)
func init() {
dbsql.Register(tracingDriverName, sqlmw.Driver(stdlib.GetDefaultDriver(), new(traceInterceptor)))
}
var (
psql = sq.StatementBuilder.PlaceholderFormat(sq.Dollar)
getRevision = psql.
Select(colXID, fmt.Sprintf("pg_snapshot_xmin(%s)", colSnapshot)).
From(tableTransaction).
OrderByClause(fmt.Sprintf("%s DESC", colXID)).
Limit(1)
createTxn = fmt.Sprintf(
"INSERT INTO %s DEFAULT VALUES RETURNING %s, pg_snapshot_xmin(%s)",
tableTransaction,
colXID,
colSnapshot,
)
getNow = psql.Select("NOW()")
tracer = otel.Tracer("spicedb/internal/datastore/postgres")
)
type sqlFilter interface {
ToSql() (string, []interface{}, error)
}
// NewPostgresDatastore initializes a SpiceDB datastore that uses a PostgreSQL
// database by leveraging manual book-keeping to implement revisioning.
//
// This datastore is also tested to be compatible with CockroachDB.
func NewPostgresDatastore(
url string,
options ...Option,
) (datastore.Datastore, error) {
ds, err := newPostgresDatastore(url, options...)
if err != nil {
return nil, err
}
return proxy.NewSeparatingContextDatastoreProxy(ds), nil
}
func newPostgresDatastore(
url string,
options ...Option,
) (datastore.Datastore, error) {
config, err := generateConfig(options)
if err != nil {
return nil, fmt.Errorf(errUnableToInstantiate, err)
}
if config.migrationPhase != "" {
log.Info().
Str("phase", config.migrationPhase).
Msg("postgres configured to use intermediate migration phase")
}
// config must be initialized by ParseConfig
pgxConfig, err := pgxpool.ParseConfig(url)
if err != nil {
return nil, fmt.Errorf(errUnableToInstantiate, err)
}
configurePool(config, pgxConfig)
initializationContext, cancelInit := context.WithTimeout(context.Background(), 5*time.Second)
defer cancelInit()
dbpool, err := pgxpool.ConnectConfig(initializationContext, pgxConfig)
if err != nil {
return nil, fmt.Errorf(errUnableToInstantiate, err)
}
// Verify that the server supports commit timestamps
var trackTSOn string
if err := dbpool.
QueryRow(initializationContext, "SHOW track_commit_timestamp;").
Scan(&trackTSOn); err != nil {
return nil, fmt.Errorf(errUnableToInstantiate, err)
}
watchEnabled := trackTSOn == "on"
if !watchEnabled {
log.Warn().Msg("watch API disabled, postgres must be run with track_commit_timestamp=on")
}
if config.enablePrometheusStats {
collector := pgxpoolprometheus.NewCollector(dbpool, map[string]string{"db_name": "spicedb"})
if err := prometheus.Register(collector); err != nil {
return nil, fmt.Errorf(errUnableToInstantiate, err)
}
if err := common.RegisterGCMetrics(); err != nil {
return nil, fmt.Errorf(errUnableToInstantiate, err)
}
}
gcCtx, cancelGc := context.WithCancel(context.Background())
quantizationPeriodNanos := config.revisionQuantization.Nanoseconds()
if quantizationPeriodNanos < 1 {
quantizationPeriodNanos = 1
}
revisionQuery := fmt.Sprintf(
querySelectRevision,
colXID,
tableTransaction,
colTimestamp,
quantizationPeriodNanos,
colSnapshot,
)
validTransactionQuery := fmt.Sprintf(
queryValidTransaction,
colXID,
tableTransaction,
colTimestamp,
config.gcWindow.Seconds(),
)
maxRevisionStaleness := time.Duration(float64(config.revisionQuantization.Nanoseconds())*
config.maxRevisionStalenessPercent) * time.Nanosecond
datastore := &pgDatastore{
CachedOptimizedRevisions: revisions.NewCachedOptimizedRevisions(
maxRevisionStaleness,
),
dburl: url,
dbpool: dbpool,
watchBufferLength: config.watchBufferLength,
optimizedRevisionQuery: revisionQuery,
validTransactionQuery: validTransactionQuery,
gcWindow: config.gcWindow,
gcInterval: config.gcInterval,
gcTimeout: config.gcMaxOperationTime,
analyzeBeforeStatistics: config.analyzeBeforeStatistics,
usersetBatchSize: config.splitAtUsersetCount,
watchEnabled: watchEnabled,
gcCtx: gcCtx,
cancelGc: cancelGc,
readTxOptions: pgx.TxOptions{IsoLevel: pgx.RepeatableRead, AccessMode: pgx.ReadOnly},
maxRetries: config.maxRetries,
}
datastore.SetOptimizedRevisionFunc(datastore.optimizedRevisionFunc)
// Start a goroutine for garbage collection.
if datastore.gcInterval > 0*time.Minute && config.gcEnabled {
datastore.gcGroup, datastore.gcCtx = errgroup.WithContext(datastore.gcCtx)
datastore.gcGroup.Go(func() error {
return common.StartGarbageCollector(
datastore.gcCtx,
datastore,
datastore.gcInterval,
datastore.gcWindow,
datastore.gcTimeout,
)
})
} else {
log.Warn().Msg("datastore background garbage collection disabled")
}
return datastore, nil
}
func configurePool(config postgresOptions, pgxConfig *pgxpool.Config) {
if config.maxOpenConns != nil {
pgxConfig.MaxConns = int32(*config.maxOpenConns)
}
if config.minOpenConns != nil {
pgxConfig.MinConns = int32(*config.minOpenConns)
}
if pgxConfig.MaxConns > 0 && pgxConfig.MinConns > 0 && pgxConfig.MaxConns < pgxConfig.MinConns {
log.Warn().Int32("max-connections", pgxConfig.MaxConns).Int32("min-connections", pgxConfig.MinConns).Msg("maximum number of connections configured is less than minimum number of connections; minimum will be used")
}
if config.connMaxIdleTime != nil {
pgxConfig.MaxConnIdleTime = *config.connMaxIdleTime
}
if config.connMaxLifetime != nil {
pgxConfig.MaxConnLifetime = *config.connMaxLifetime
}
if config.healthCheckPeriod != nil {
pgxConfig.HealthCheckPeriod = *config.healthCheckPeriod
}
pgxcommon.ConfigurePGXLogger(pgxConfig.ConnConfig)
}
type pgDatastore struct {
*revisions.CachedOptimizedRevisions
dburl string
dbpool *pgxpool.Pool
watchBufferLength uint16
optimizedRevisionQuery string
validTransactionQuery string
gcWindow time.Duration
gcInterval time.Duration
gcTimeout time.Duration
usersetBatchSize uint16
analyzeBeforeStatistics bool
readTxOptions pgx.TxOptions
maxRetries uint8
watchEnabled bool
gcGroup *errgroup.Group
gcCtx context.Context
cancelGc context.CancelFunc
}
func (pgd *pgDatastore) SnapshotReader(revRaw datastore.Revision) datastore.Reader {
rev := revRaw.(postgresRevision)
createTxFunc := func(ctx context.Context) (pgx.Tx, common.TxCleanupFunc, error) {
tx, err := pgd.dbpool.BeginTx(ctx, pgd.readTxOptions)
if err != nil {
return nil, nil, err
}
cleanup := func(ctx context.Context) {
if err := tx.Rollback(ctx); err != nil {
log.Ctx(ctx).Err(err).Msg("error running transaction cleanup function")
}
}
return tx, cleanup, nil
}
querySplitter := common.TupleQuerySplitter{
Executor: pgxcommon.NewPGXExecutor(createTxFunc),
UsersetBatchSize: pgd.usersetBatchSize,
}
return &pgReader{
createTxFunc,
querySplitter,
buildLivingObjectFilterForRevision(rev),
}
}
func noCleanup(context.Context) {}
// ReadWriteTx tarts a read/write transaction, which will be committed if no error is
// returned and rolled back if an error is returned.
func (pgd *pgDatastore) ReadWriteTx(
ctx context.Context,
fn datastore.TxUserFunc,
) (datastore.Revision, error) {
var err error
for i := uint8(0); i <= pgd.maxRetries; i++ {
var newXID, newXmin xid8
err = pgd.dbpool.BeginTxFunc(ctx, pgx.TxOptions{IsoLevel: pgx.Serializable}, func(tx pgx.Tx) error {
var err error
newXID, newXmin, err = createNewTransaction(ctx, tx)
if err != nil {
return err
}
longLivedTx := func(context.Context) (pgx.Tx, common.TxCleanupFunc, error) {
return tx, noCleanup, nil
}
querySplitter := common.TupleQuerySplitter{
Executor: pgxcommon.NewPGXExecutor(longLivedTx),
UsersetBatchSize: pgd.usersetBatchSize,
}
rwt := &pgReadWriteTXN{
&pgReader{
longLivedTx,
querySplitter,
currentlyLivingObjects,
},
tx,
newXID,
}
return fn(rwt)
})
if err != nil {
if errorRetryable(err) {
continue
}
return datastore.NoRevision, err
}
return postgresRevision{newXID, newXmin}, nil
}
return datastore.NoRevision, fmt.Errorf("max retries exceeded: %w", err)
}
func (pgd *pgDatastore) Close() error {
pgd.cancelGc()
if pgd.gcGroup != nil {
err := pgd.gcGroup.Wait()
log.Warn().Err(err).Msg("completed shutdown of postgres datastore")
}
pgd.dbpool.Close()
return nil
}
func errorRetryable(err error) bool {
var pgerr *pgconn.PgError
if !errors.As(err, &pgerr) {
log.Debug().Err(err).Msg("couldn't determine a sqlstate error code")
return false
}
// We need to check unique constraint here because some versions of postgres have an error where
// unique constraint violations are raised instead of serialization errors.
// (e.g. https://www.postgresql.org/message-id/flat/CAGPCyEZG76zjv7S31v_xPeLNRuzj-m%3DY2GOY7PEzu7vhB%3DyQog%40mail.gmail.com)
return pgerr.SQLState() == pgSerializationFailure || pgerr.SQLState() == pgUniqueConstraintViolation
}
func (pgd *pgDatastore) IsReady(ctx context.Context) (bool, error) {
headMigration, err := migrations.DatabaseMigrations.HeadRevision()
if err != nil {
return false, fmt.Errorf("invalid head migration found for postgres: %w", err)
}
currentRevision, err := migrations.NewAlembicPostgresDriver(pgd.dburl)
if err != nil {
return false, err
}
defer currentRevision.Close(ctx)
version, err := currentRevision.Version(ctx)
if err != nil {
return false, err
}
return version == headMigration, nil
}
func (pgd *pgDatastore) Features(ctx context.Context) (*datastore.Features, error) {
return &datastore.Features{Watch: datastore.Feature{Enabled: pgd.watchEnabled}}, nil
}
func buildLivingObjectFilterForRevision(revision postgresRevision) queryFilterer {
createdBeforeTXN := sq.Expr(fmt.Sprintf(
snapshotAlive,
colCreatedXid,
colSnapshot,
tableTransaction,
colXID,
sq.Placeholders(1),
), revision.tx, true)
alreadyAlive := sq.Or{
createdBeforeTXN,
sq.Expr(colCreatedXid+" = "+sq.Placeholders(1), revision.tx),
}
deletedAfterTXN := sq.Expr(fmt.Sprintf(
snapshotAlive,
colDeletedXid,
colSnapshot,
tableTransaction,
colXID,
sq.Placeholders(1),
), revision.tx, false)
notYetDead := sq.And{
deletedAfterTXN,
sq.Expr(colDeletedXid+" <> "+sq.Placeholders(1), revision.tx),
}
return func(original sq.SelectBuilder) sq.SelectBuilder {
return original.Where(alreadyAlive).Where(notYetDead)
}
}
func currentlyLivingObjects(original sq.SelectBuilder) sq.SelectBuilder {
return original.Where(sq.Eq{colDeletedXid: liveDeletedTxnID})
}
var _ datastore.Datastore = &pgDatastore{}