8888557 · reshape · git.iko.soy

git.iko.soy/reshape

Check for new schema rather than old in helper

We want it to be possible for Reshape to be adopted for existing databases with an existing schema. To make this possible, we can't check if the schema path matches the current migration as there won't be a current migration at first. Instead we'll compare against the target migration. The next step in making Reshape work with existing databases is to not automatically complete the first migration. This will not be safe for an existing application adopting Reshape.

commit8888557c3848f037a86822b5a2778e9879324d84 authorfabianlindfors <fabian@flapplabs.se> dateMon 31 Jan 2022, 19:53 (5 years ago) parent4e93a39

6 files changed+13−26

compare with main

unifiedsplit

src/helpers.rs+7−16 src/lib.rs+2−2 src/migrations/add_column.rs+1−1 src/migrations/alter_column.rs+2−2 src/migrations/common.rs−4 src/migrations/remove_column.rs+1−1

src/helpers.rs+7−16

@@ -2,37 +2,28 @@ use anyhow::Context;

33use crate::db::Conn;

5−pub fn set_up_helpers(db: &mut dyn Conn, current_migration: &Option<String>) -> anyhow::Result<()> {

6− let predicate = if let Some(current_migration) = current_migration {

7− format!(

8− "current_setting('search_path') = 'migration_{}' OR setting_bool",

9− current_migration

10− )

11− } else {

12− "setting_bool".to_string()

13− };

14−

5+pub fn set_up_helpers(db: &mut dyn Conn, target_migration: &str) -> anyhow::Result<()> {

156 let query = format!(

167 "

17− CREATE OR REPLACE FUNCTION reshape.is_old_schema()

8+ CREATE OR REPLACE FUNCTION reshape.is_new_schema()

189 RETURNS BOOLEAN AS $$

1910 DECLARE

20− setting TEXT := current_setting('reshape.is_old_schema', TRUE);

11+ setting TEXT := current_setting('reshape.is_new_schema', TRUE);

2112 setting_bool BOOLEAN := setting IS NOT NULL AND setting = 'YES';

2213 BEGIN

23− RETURN {};

14+ RETURN current_setting('search_path') = 'migration_{}' OR setting_bool;

2415 END

2516 $$ language 'plpgsql';

2617 ",

27− predicate

18+ target_migration,

2819 );

2920 db.query(&query)

30− .context("failed creating helper function reshape.is_old_schema()")?;

21+ .context("failed creating helper function reshape.is_new_schema()")?;

3122

3223 Ok(())

3324}

3425

3526pub fn tear_down_helpers(db: &mut dyn Conn) -> anyhow::Result<()> {

36− db.query("DROP FUNCTION IF EXISTS reshape.is_old_schema;")?;

27+ db.query("DROP FUNCTION IF EXISTS reshape.is_new_schema;")?;

3728 Ok(())

3829}

src/lib.rs+2−2

@@ -189,7 +189,8 @@ fn migrate(

189189

190190 println!("Applying {} migrations\n", remaining_migrations.len());

191191

192− helpers::set_up_helpers(db, &current_migration).context("failed to set up helpers")?;

192+ let target_migration = remaining_migrations.last().unwrap().name.to_string();

193+ helpers::set_up_helpers(db, &target_migration).context("failed to set up helpers")?;

193194

194195 let mut new_schema = Schema::new();

195196 let mut last_migration_index = usize::MAX;

@@ -244,7 +245,6 @@ fn migrate(

244245 }

245246

246247 // Create schema and views for migration

247− let target_migration = remaining_migrations.last().unwrap().name.to_string();

248248 create_schema_for_migration(db, &target_migration, &new_schema)

249249 .with_context(|| format!("failed to create schema for migration {}", target_migration))?;

250250

src/migrations/add_column.rs+1−1

@@ -106,7 +106,7 @@ impl Action for AddColumn {

106106 CREATE OR REPLACE FUNCTION {trigger_name}()

107107 RETURNS TRIGGER AS $$

108108 BEGIN

109− IF reshape.is_old_schema() THEN

109+ IF NOT reshape.is_new_schema() THEN

110110 DECLARE

111111 {declarations}

112112 BEGIN

src/migrations/alter_column.rs+2−2

@@ -103,7 +103,7 @@ impl Action for AlterColumn {

103103 CREATE OR REPLACE FUNCTION {up_trigger}()

104104 RETURNS TRIGGER AS $$

105105 BEGIN

106− IF reshape.is_old_schema() THEN

106+ IF NOT reshape.is_new_schema() THEN

107107 DECLARE

108108 {declarations}

109109 {existing_column} public.{table}.{existing_column_real}%TYPE := NEW.{existing_column_real};

@@ -121,7 +121,7 @@ impl Action for AlterColumn {

121121 CREATE OR REPLACE FUNCTION {down_trigger}()

122122 RETURNS TRIGGER AS $$

123123 BEGIN

124− IF NOT reshape.is_old_schema() THEN

124+ IF reshape.is_new_schema() THEN

125125 DECLARE

126126 {declarations}

127127 {existing_column} public.{table}.{temp_column}%TYPE := NEW.{temp_column};

src/migrations/common.rs−4

@@ -72,8 +72,6 @@ impl ToSql for PostgresRawValue {

7272pub fn batch_touch_rows(db: &mut dyn Conn, table: &str, column: &str) -> anyhow::Result<()> {

7373 const BATCH_SIZE: u16 = 1000;

7474

75− db.query("SET reshape.is_old_schema = 'YES'")?;

76−

7775 let mut cursor: Option<PostgresRawValue> = None;

7876

7977 loop {

@@ -152,8 +150,6 @@ pub fn batch_touch_rows(db: &mut dyn Conn, table: &str, column: &str) -> anyhow:

152150 cursor = last_value

153151 }

154152

155− db.query("SET reshape.is_old_schema = ''")?;

156−

157153 Ok(())

158154}

159155

src/migrations/remove_column.rs+1−1

@@ -61,7 +61,7 @@ impl Action for RemoveColumn {

6161 CREATE OR REPLACE FUNCTION {trigger_name}()

6262 RETURNS TRIGGER AS $$

6363 BEGIN

64− IF NOT reshape.is_old_schema() IS NULL THEN

64+ IF reshape.is_new_schema() THEN

6565 DECLARE

6666 {declarations}

6767 BEGIN