make annotations nullable to fix migration (#917)

make app.annotations  and routes.annotations non-null  always

This resolves a schema ambiguity that arrose in the annotations layer that would result in different schemas depending on whether you started afresh or migrated up.

api/datastore/sql/migrations/10_add_app_id.go

@@ -10,6 +10,8 @@ import (
 	"github.com/jmoiron/sqlx"
 )
 
+// routes.annotations is retconned to NULLABLE here to allow migrations to proceed
+// see migrations 11 and 12 that fix this back up to NOT NULL
 var sqlStatements = [...]string{`CREATE TABLE IF NOT EXISTS routes (
 	app_id varchar(256) NOT NULL,
 	path varchar(256) NOT NULL,
@@ -22,7 +24,7 @@ var sqlStatements = [...]string{`CREATE TABLE IF NOT EXISTS routes (
 	type varchar(16) NOT NULL,
 	headers text NOT NULL,
 	config text NOT NULL,
-	annotations text NOT NULL,
+	annotations text,
 	created_at text,
 	updated_at varchar(256),
 	PRIMARY KEY (app_id, path)

api/datastore/sql/migrations/11_fix_annotations_migrations_route.go

@@ -0,0 +1,86 @@
+package migrations
+
+import (
+	"context"
+
+	"github.com/fnproject/fn/api/datastore/sql/migratex"
+	"github.com/jmoiron/sqlx"
+)
+
+func up11(ctx context.Context, tx *sqlx.Tx) error {
+
+	// clear out any old null values
+	// on mysql this may result in some in-flight changes being missed and an error on the alter table below
+	_, err := tx.ExecContext(ctx, `UPDATE routes set annotations=(CASE WHEN annotations IS NULL THEN '' ELSE annotations END);`)
+	if err != nil {
+		return err
+	}
+
+	switch tx.DriverName() {
+
+	case "mysql":
+		// this implicitly commits but its the last command so should be safe.
+		_, err := tx.ExecContext(ctx, "ALTER TABLE routes MODIFY annotations TEXT NOT NULL;")
+		return err
+	case "postgres", "pgx":
+		_, err := tx.ExecContext(ctx, "ALTER TABLE routes ALTER COLUMN annotations DROP NOT NULL;")
+		return err
+	default:
+		_, err := tx.ExecContext(ctx, "ALTER TABLE routes RENAME TO old_routes;")
+
+		if err != nil {
+			return err
+		}
+
+		newTable := `CREATE TABLE routes (
+	app_id varchar(256) NOT NULL,
+	path varchar(256) NOT NULL,
+	image varchar(256) NOT NULL,
+	format varchar(16) NOT NULL,
+	memory int NOT NULL,
+	cpus int,
+	timeout int NOT NULL,
+	idle_timeout int NOT NULL,
+	type varchar(16) NOT NULL,
+	headers text NOT NULL,
+	config text NOT NULL,
+	annotations text NOT NULL,
+	created_at text,
+	updated_at varchar(256),
+	PRIMARY KEY (app_id, path)
+);`
+		_, err = tx.ExecContext(ctx, newTable)
+		if err != nil {
+			return err
+		}
+		insertQuery := `INSERT INTO routes(app_id,path,image,format,memory,cpus,timeout,idle_timeout,type,headers,config,annotations,created_at,updated_at) 
+	  					SELECT  app_id,path,image,format,memory,cpus,timeout,idle_timeout,type,headers,config,annotations,created_at,updated_at FROM old_routes;`
+
+		_, err = tx.ExecContext(ctx, insertQuery)
+		if err != nil {
+			return err
+		}
+
+		_, err = tx.ExecContext(ctx, "DROP TABLE old_routes;")
+		if err != nil {
+			return err
+		}
+
+		return err
+
+	}
+
+}
+
+func down11(ctx context.Context, tx *sqlx.Tx) error {
+	// annotations are in an indeterminate state so we leave this change as it is
+	return nil
+}
+
+func init() {
+	Migrations = append(Migrations, &migratex.MigFields{
+		VersionFunc: vfunc(11),
+		UpFunc:      up11,
+		DownFunc:    down11,
+	})
+}

api/datastore/sql/migrations/12_fix_annotations_migrations_app.go

@@ -0,0 +1,77 @@
+package migrations
+
+import (
+	"context"
+
+	"github.com/fnproject/fn/api/datastore/sql/migratex"
+	"github.com/jmoiron/sqlx"
+)
+
+func up12(ctx context.Context, tx *sqlx.Tx) error {
+
+	// clear out any old null values
+	// on mysql this may result in some in-flight changes being missed and an error on the alter table below
+	_, err := tx.ExecContext(ctx, `UPDATE apps set annotations=(CASE WHEN annotations IS NULL THEN '' ELSE annotations END);`)
+	if err != nil {
+		return err
+	}
+
+	switch tx.DriverName() {
+
+	case "mysql":
+		// this implicitly commits but its the last command so should be safe.
+		_, err := tx.ExecContext(ctx, "ALTER TABLE apps MODIFY annotations TEXT NOT NULL;")
+		return err
+	case "postgres", "pgx":
+		_, err := tx.ExecContext(ctx, "ALTER TABLE apps ALTER COLUMN annotations DROP NOT NULL;")
+		return err
+	default: // nuclear option, replace the table using sqlite safe DDL
+		_, err := tx.ExecContext(ctx, "ALTER TABLE apps RENAME TO old_apps;")
+
+		if err != nil {
+			return err
+		}
+
+		newTable := `CREATE TABLE apps (
+	id varchar(256),
+	name varchar(256) NOT NULL PRIMARY KEY,
+	config text NOT NULL,
+	annotations text NOT NULL,
+	created_at varchar(256),
+	updated_at varchar(256)
+);`
+		_, err = tx.ExecContext(ctx, newTable)
+		if err != nil {
+			return err
+		}
+		insertQuery := `INSERT INTO apps(id,name,config,annotations,created_at,updated_at) 
+	  					SELECT  id,name,config,annotations,created_at,updated_at FROM old_apps;`
+
+		_, err = tx.ExecContext(ctx, insertQuery)
+		if err != nil {
+			return err
+		}
+
+		_, err = tx.ExecContext(ctx, "DROP TABLE old_apps;")
+		if err != nil {
+			return err
+		}
+
+		return err
+
+	}
+
+}
+
+func down12(ctx context.Context, tx *sqlx.Tx) error {
+	// annotations are in an indeterminate state so we leave this change as it is
+	return nil
+}
+
+func init() {
+	Migrations = append(Migrations, &migratex.MigFields{
+		VersionFunc: vfunc(12),
+		UpFunc:      up12,
+		DownFunc:    down12,
+	})
+}