fix(engine): use the correct path to the data directory for the promote instance (#342)

Author: agneum

engine/.golangci.yml

@@ -82,7 +82,7 @@ linters:
     - megacheck
     - misspell
     - prealloc
-#    - revive # temporarily disabled: https://gitlab.com/postgres-ai/database-lab/-/merge_requests/498
+    - revive
     - structcheck
     - stylecheck
     - unconvert

engine/internal/retrieval/engine/postgres/physical/pgbackrest.go

@@ -16,35 +16,36 @@ const (
 
 // pgbackrest defines a pgBackRest as an archival restoration tool.
 type pgbackrest struct {
-	pgDataDir string
-	options   pgbackrestOptions
+	options pgbackrestOptions
 }
 
 type pgbackrestOptions struct {
 	Stanza    string `yaml:"stanza"`
 	ForceInit bool   `yaml:"forceInit"`
 }
 
-func newPgBackRest(pgDataDir string, options pgbackrestOptions) *pgbackrest {
+func newPgBackRest(options pgbackrestOptions) *pgbackrest {
 	return &pgbackrest{
-		pgDataDir: pgDataDir,
-		options:   options,
+		options: options,
 	}
 }
 
 // GetRestoreCommand returns a command to restore data.
 func (p *pgbackrest) GetRestoreCommand() string {
+	restoreCmd := fmt.Sprintf("sudo -Eu postgres pgbackrest --type=standby --pg1-path=${PGDATA} --stanza=%[1]s restore "+
+		"--recovery-option=restore_command='pgbackrest --pg1-path=${PGDATA} --stanza=%[1]s archive-get %%f %%p'", p.options.Stanza)
+
 	if p.options.ForceInit {
-		return fmt.Sprintf("sudo -Eu postgres pgbackrest --delta --type=standby --pg1-path=%s --stanza=%s restore", p.pgDataDir, p.options.Stanza)
+		restoreCmd += " --delta"
 	}
 
-	return fmt.Sprintf("sudo -Eu postgres pgbackrest --type=standby --pg1-path=%s --stanza=%s restore", p.pgDataDir, p.options.Stanza)
+	return restoreCmd
 }
 
 // GetRecoveryConfig returns a recovery config to restore data.
 func (p *pgbackrest) GetRecoveryConfig(pgVersion float64) map[string]string {
 	recoveryCfg := map[string]string{
-		"restore_command": fmt.Sprintf("pgbackrest --pg1-path=%s --stanza=%s archive-get %%f %%p", p.pgDataDir, p.options.Stanza),
+		"restore_command": fmt.Sprintf("pgbackrest --pg1-path=${PGDATA} --stanza=%s archive-get %%f %%p", p.options.Stanza),
 	}
 
 	if pgVersion < defaults.PGVersion12 {

engine/internal/retrieval/engine/postgres/physical/pgbackrest_test.go

@@ -7,31 +7,33 @@ import (
 )
 
 func TestPgBackRestRecoveryConfig(t *testing.T) {
-	pgbackrest := newPgBackRest("dataDir", pgbackrestOptions{Stanza: "stanzaName"})
+	pgbackrest := newPgBackRest(pgbackrestOptions{Stanza: "stanzaName"})
 
 	recoveryConfig := pgbackrest.GetRecoveryConfig(11.7)
 	expectedResponse11 := map[string]string{
-		"restore_command":          "pgbackrest --pg1-path=dataDir --stanza=stanzaName archive-get %f %p",
+		"restore_command":          "pgbackrest --pg1-path=${PGDATA} --stanza=stanzaName archive-get %f %p",
 		"recovery_target_timeline": "latest",
 	}
 	assert.Equal(t, expectedResponse11, recoveryConfig)
 
 	recoveryConfig = pgbackrest.GetRecoveryConfig(12.3)
 	expectedResponse12 := map[string]string{
-		"restore_command": "pgbackrest --pg1-path=dataDir --stanza=stanzaName archive-get %f %p",
+		"restore_command": "pgbackrest --pg1-path=${PGDATA} --stanza=stanzaName archive-get %f %p",
 	}
 	assert.Equal(t, expectedResponse12, recoveryConfig)
 }
 
 func TestPgBackRestRestoreCommand(t *testing.T) {
-	pgbackrest := newPgBackRest("dataDir", pgbackrestOptions{Stanza: "stanzaName"})
+	pgbackrest := newPgBackRest(pgbackrestOptions{Stanza: "stanzaName"})
 
 	restoreCmd := pgbackrest.GetRestoreCommand()
-	expectedResponse := "sudo -Eu postgres pgbackrest --type=standby --pg1-path=dataDir --stanza=stanzaName restore"
+	expectedResponse := "sudo -Eu postgres pgbackrest --type=standby --pg1-path=${PGDATA} --stanza=stanzaName restore " +
+		"--recovery-option=restore_command='pgbackrest --pg1-path=${PGDATA} --stanza=stanzaName archive-get %f %p'"
 	assert.Equal(t, expectedResponse, restoreCmd)
 
 	pgbackrest.options.ForceInit = true
 	restoreCmd = pgbackrest.GetRestoreCommand()
-	expectedResponse = "sudo -Eu postgres pgbackrest --delta --type=standby --pg1-path=dataDir --stanza=stanzaName restore"
+	expectedResponse = "sudo -Eu postgres pgbackrest --type=standby --pg1-path=${PGDATA} --stanza=stanzaName restore " +
+		"--recovery-option=restore_command='pgbackrest --pg1-path=${PGDATA} --stanza=stanzaName archive-get %f %p' --delta"
 	assert.Equal(t, expectedResponse, restoreCmd)
 }

engine/internal/retrieval/engine/postgres/physical/physical.go

@@ -132,7 +132,7 @@ func (r *RestoreJob) getRestorer(tool string) (restorer, error) {
 		return newWALG(r.fsPool.DataDir(), r.WALG), nil
 
 	case pgbackrestTool:
-		return newPgBackRest(r.fsPool.DataDir(), r.PgBackRest), nil
+		return newPgBackRest(r.PgBackRest), nil
 
 	case customTool:
 		return newCustomTool(r.CustomTool), nil