cmd/relui: add migrate-down-up flag

Adds a migrate-down-up flag that re-runs the down and up steps of the
last migration. This is useful when developing migrations, making it
easier to make changes.

For golang/go#47401

Change-Id: I21369bc6792220a02641109edf0f628f9dc18981
Reviewed-on: https://go-review.googlesource.com/c/build/+/353409
Trust: Alexander Rakoczy <[email protected]>
Run-TryBot: Alexander Rakoczy <[email protected]>
TryBot-Result: Go Bot <[email protected]>
Reviewed-by: Heschi Kreinick <[email protected]>

Author: toothrot

cmd/relui/Makefile

@@ -6,8 +6,6 @@ VERSION := $(shell ../coordinator/version.sh)
 DOCKER_TAG := golang/relui:$(VERSION)
 
 INTERNAL_PATH := ../../internal/relui
-MIGRATION_FILES := $(wildcard $(INTERNAL_PATH)/migrations/*.sql)
-GO_FILES := $(shell find $(INTERNAL_PATH) -name "*.go")
 
 POSTGRES_DATA_DEV := "postgres-data-dev:/var/lib/postgresql/data"
 POSTGRES_RUN_DEV := "postgres-run-dev:/var/run/postgresql"
@@ -31,9 +29,13 @@ postgres-dev: $(DEV_CFG)/pgpass
 		-e POSTGRES_PASSWORD_FILE=/run/secrets/pgpass \
 		postgres:13
 
-schema.sql: $(MIGRATION_FILES) $(GO_FILES)
-	docker build -f Dockerfile -t golang/relui:$(VERSION) ../..
-	docker run --rm --name=relui-dev-migrate -v $(POSTGRES_RUN_DEV) -e PGUSER=$(POSTGRES_USER) -e PGDATABASE=relui-dev $(DOCKER_TAG) --only-migrate
+migrate: docker
+	docker run --rm --name=relui-dev-migrate -v $(POSTGRES_RUN_DEV) -e PGUSER=$(POSTGRES_USER) -e PGDATABASE=relui-dev $(DOCKER_TAG) --migrate-only
+
+migrate-down-up: docker
+	docker run --rm --name=relui-dev-migrate -v $(POSTGRES_RUN_DEV) -e PGUSER=$(POSTGRES_USER) -e PGDATABASE=relui-dev $(DOCKER_TAG) --migrate-down-up
+
+schema.sql: migrate
 	docker exec postgres-dev pg_dump --username=$(POSTGRES_USER) --schema-only relui-dev > schema.sql
 
 .PHONY: test
@@ -47,11 +49,3 @@ docker:
 .PHONY: docker-test
 docker-test:
 	docker build -f Dockerfile.test -t golang/relui-test:$(VERSION) ../..
-
-$(DEV_CFG):
-	mkdir -p $(DEV_CFG)
-
-$(DEV_CFG)/pgpass: $(DEV_CFG)
-	touch $(DEV_CFG)/pgpass
-	chmod 0600 $(DEV_CFG)/pgpass
-	openssl rand -hex -out $(DEV_CFG)/pgpass 32

cmd/relui/README.md

@@ -55,7 +55,7 @@ go run -tags pgx github.com/golang-migrate/migrate/v4/cmd/migrate \
 Migrations are automatically ran on application launch. Updating
 schema.sql, as documented below, will also run migrations. "Down"
 migrations are not automatically run and must be manually invoked in
-`psql`.
+`psql`, or by the `--migrate-down-up` flag or `make migrate-down-up`.
 
 #### cmd/relui/schema.sql
 

cmd/relui/main.go

@@ -17,7 +17,8 @@ import (
 
 var (
 	pgConnect   = flag.String("pg-connect", "", "Postgres connection string or URI. If empty, libpq connection defaults are used.")
-	onlyMigrate = flag.Bool("only-migrate", false, "Exit after running migrations. Migrations are run by default.")
+	migrateOnly = flag.Bool("migrate-only", false, "Exit after running migrations. Migrations are run by default.")
+	downUp      = flag.Bool("migrate-down-up", false, "Run all Up migration steps, then the last down migration step, followed by the final up migration. Exits after completion.")
 )
 
 func main() {
@@ -26,7 +27,13 @@ func main() {
 	if err := relui.InitDB(ctx, *pgConnect); err != nil {
 		log.Fatalf("relui.InitDB() = %v", err)
 	}
-	if *onlyMigrate {
+	if *migrateOnly {
+		return
+	}
+	if *downUp {
+		if err := relui.MigrateDB(*pgConnect, true); err != nil {
+			log.Fatalf("relui.MigrateDB() = %v", err)
+		}
 		return
 	}
 	db, err := pgxpool.Connect(ctx, *pgConnect)

internal/relui/store.go

@@ -33,16 +33,18 @@ func InitDB(ctx context.Context, conn string) error {
 	if err := CreateDBIfNotExists(ctx, cfg); err != nil {
 		return err
 	}
-	if err := MigrateDB(conn); err != nil {
+	if err := MigrateDB(conn, false); err != nil {
 		return err
 	}
 	return nil
 }
 
 // MigrateDB applies all migrations to the database specified in conn.
 //
-// Any key/value or URI string compatible with libpq is valid.
-func MigrateDB(conn string) error {
+// Any key/value or URI string compatible with libpq is a valid conn.
+// If downUp is true, all migrations will be run, then the down and up
+// migrations of the final migration are run.
+func MigrateDB(conn string, downUp bool) error {
 	cfg, err := pgx.ParseConfig(conn)
 	if err != nil {
 		return fmt.Errorf("pgx.ParseConfig() = %w", err)
@@ -70,6 +72,14 @@ func MigrateDB(conn string) error {
 	if err := m.Up(); err != nil && !errors.Is(err, migrate.ErrNoChange) {
 		return fmt.Errorf("m.Up() = %w", err)
 	}
+	if downUp {
+		if err := m.Steps(-1); err != nil {
+			return fmt.Errorf("m.Steps(%d) = %w", -1, err)
+		}
+		if err := m.Up(); err != nil {
+			return fmt.Errorf("m.Up() = %w", err)
+		}
+	}
 	db.Close()
 	return nil
 }