90 lines
2.5 KiB
Go
90 lines
2.5 KiB
Go
/*
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Copyright 2016 GitHub Inc.
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See https://github.com/github/gh-osc/blob/master/LICENSE
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*/
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package logic
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import (
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"fmt"
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"github.com/github/gh-osc/go/base"
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"github.com/outbrain/golib/log"
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)
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// Migrator is the main schema migration flow manager.
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type Migrator struct {
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inspector *Inspector
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applier *Applier
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eventsStreamer *EventsStreamer
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migrationContext *base.MigrationContext
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}
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func NewMigrator() *Migrator {
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return &Migrator{
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migrationContext: base.GetMigrationContext(),
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}
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}
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func (this *Migrator) Migrate() (err error) {
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this.inspector = NewInspector()
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if err := this.inspector.InitDBConnections(); err != nil {
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return err
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}
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if this.migrationContext.MasterConnectionConfig, err = this.inspector.getMasterConnectionConfig(); err != nil {
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return err
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}
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if this.migrationContext.IsRunningOnMaster() && !this.migrationContext.AllowedRunningOnMaster {
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return fmt.Errorf("It seems like this migration attempt to run directly on master. Preferably it would be executed on a replica (and this reduces load from the master). To proceed please provide --allow-on-master")
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}
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log.Infof("Master found to be %+v", this.migrationContext.MasterConnectionConfig.Key)
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uniqueKeys, err := this.inspector.InspectOriginalTable()
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if err != nil {
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return err
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}
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this.eventsStreamer = NewEventsStreamer()
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if err := this.eventsStreamer.InitDBConnections(); err != nil {
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return err
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}
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this.applier = NewApplier()
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if err := this.applier.InitDBConnections(); err != nil {
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return err
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}
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if err := this.applier.CreateGhostTable(); err != nil {
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log.Errorf("Unable to create ghost table, see further error details. Perhaps a previous migration failed without dropping the table? Bailing out")
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return err
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}
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if err := this.applier.AlterGhost(); err != nil {
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log.Errorf("Unable to ALTER ghost table, see further error details. Bailing out")
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return err
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}
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this.migrationContext.UniqueKey = uniqueKeys[0] // TODO. Need to wait on replica till the ghost table exists and get shared keys
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if err := this.applier.ReadMigrationRangeValues(); err != nil {
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return err
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}
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for {
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isComplete, err := this.applier.IterationIsComplete()
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if err != nil {
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return err
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}
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if isComplete {
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break
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}
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if err = this.applier.CalculateNextIterationRangeEndValues(); err != nil {
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return err
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}
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if err = this.applier.ApplyIterationInsertQuery(); err != nil {
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return err
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}
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this.migrationContext.Iteration++
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}
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// if err := this.applier.IterateTable(uniqueKeys[0]); err != nil {
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// return err
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// }
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return nil
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}
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