declarative-sql-migrations
what?
A postgres migration tool based on diffing 2 schemata.
API
-- a type representing an alteration
type alteration as (
"order" int, -- smaller number means higher priority
type ddl_type,
ddl text,
details jsonb
);
-- execute or retries (expentional backoff with jitter) any statement that throws any of sqlstates
procedure exec(
ddl text,
lock_timeout text = '50ms',
max_attempts int = 30,
cap_ms bigint = 60000,
base_ms bigint = 10,
sqlstates text[] default '{}'::text[] -- see https://www.postgresql.org/docs/current/errcodes-appendix.html
);
-- returns the set of all alterations to make "target" similar to "desired"
function alterations(
desired text, -- the reference schema
target text -- the schema to alter,
cascade bool default false, -- include "CASCADE" in emitted statements that support it
) returns setof alteration
strict parallel restricted;
-- prints and optionnaly executes all alterations
procedure migrate(
desired text, -- the reference schema
target text -- the schema to alter
dry_run bool default true, -- only print
keep_data bool default false, -- do not emit "DROP" statements that remove data
cascade bool default false, -- include "CASCADE" in emitted statements that support it
lock_timeout text = '50ms',
max_attempts int = 30,
cap_ms bigint = 60000,
base_ms bigint = 10,
sqlstates text[] default '{}'::text[]
);how?
psql -q -f example/desired.sql -f src/main.sql -c "call pgdiff.migrate('desired', 'target',
dry_run => true
)"run tests
psql -q -f src/main.sql -f test_init.sql $(find test -name '*.sql' -printf ' -f %h/%f\n' | sort -V | xargs)example
set search_path to pgdiff;
drop schema if exists desired cascade;
create schema desired;
create table desired.test1 (
test1_id int not null primary key,
name text unique not null default 1,
price int check (price > 0)
);
create index test1_name on desired.test1 (name);
create table desired.test2 (
test2_id int not null primary key,
test1_id int not null references desired.test1 (test1_id) deferrable
);
drop schema if exists target cascade;
select * from pgdiff.alterations('desired', 'target') a;
-- create schema target │ 0 │ create schema │ {"schema_name": "target"}
-- create table target.test1 () │ 1 │ create table │ {"table_name": "test1", "schema_name": "target"}
-- create table target.test2 () │ 1 │ create table │ {"table_name": "test2", "schema_name": "target"}
-- alter table target.test1 add column name text not null default 1 │ 2 │ add column │ {"data_type": "text", "table_name": "test1", "column_name": "name", "is_nullable": "NO", "schema_name": "target", "column_default": "1"}
-- alter table target.test1 add column price integer │ 2 │ add column │ {"data_type": "integer", "table_name": "test1", "column_name": "price", "is_nullable": "YES", "schema_name": "target", "column_default": null}
-- alter table target.test2 add column test1_id integer not null │ 2 │ add column │ {"data_type": "integer", "table_name": "test2", "column_name": "test1_id", "is_nullable": "NO", "schema_name": "target", "column_default": null}
-- alter table target.test1 add column test1_id integer not null │ 2 │ add column │ {"data_type": "integer", "table_name": "test1", "column_name": "test1_id", "is_nullable": "NO", "schema_name": "target", "column_default": null}
-- alter table target.test2 add column test2_id integer not null │ 2 │ add column │ {"data_type": "integer", "table_name": "test2", "column_name": "test2_id", "is_nullable": "NO", "schema_name": "target", "column_default": null}
-- alter table target.test1 add constraint test1_pkey PRIMARY KEY (test1_id) │ 4 │ alter table add constraint │ {"table_name": "test1", "schema_name": "target", "constraint_name": "test1_pkey"}
-- alter table target.test2 add constraint test2_pkey PRIMARY KEY (test2_id) │ 4 │ alter table add constraint │ {"table_name": "test2", "schema_name": "target", "constraint_name": "test2_pkey"}
-- alter table target.test1 add constraint test1_name_key UNIQUE (name) │ 5 │ alter table add constraint │ {"table_name": "test1", "schema_name": "target", "constraint_name": "test1_name_key"}
-- alter table target.test1 add constraint test1_price_check CHECK ((price > 0)) │ 5 │ alter table add constraint │ {"table_name": "test1", "schema_name": "target", "constraint_name": "test1_price_check"}
-- alter table target.test2 add constraint test2_test1_id_fkey FOREIGN KEY (test1_id) REFERENCES target.test1(test1_id) DEFERRABLE │ 5 │ alter table add constraint │ {"test2", "schema_name": "target", "constraint_name": "test2_test1_id_fkey"}
-- CREATE INDEX test1_name ON target.test1 USING btree (name) │ 6 │ create index │ {"index_name": "test1_name", "table_name": "desired.test1", "schema_name": "target"}
call pgdiff.migrate('desired', 'target',
dry_run => false
);
alter table desired.test1 add column test text not null default 'ah' check (length(test) > 0);
select * from pgdiff.alterations('desired', 'target') a;
-- alter table target.test1 add column test text not null default 'ah'::text │ 2 │ add column │ {"data_type": "text", "table_name": "test1", "column_name": "test", "is_nullable": "NO", "schema_name": "target", "column_default": "'ah'::text"}
-- alter table target.test1 add constraint test1_test_check CHECK ((length(test) > 0)) │ 5 │ alter table add constraint │ {"table_name": "test1", "schema_name": "target", "constraint_name": "test1_test_check"}
call pgdiff.migrate('desired', 'target',
dry_run => false
);
select * from pgdiff.alterations('desired', 'target') a;
-- done!hacking
live reload
inotifywait -e create -e close_write -m -r --format='%w%f' \
src test* \
| xargs -I{} psql --single-transaction -f {}
validate records
create table test1 (
id int not null,
content text not null check (length(content) > 0),
age int check (age > 18),
work int not null,
check ((age >= 18 and work < 2 ) or (age < 18 and work > 2))
);
select * from pgdiff.violations('{"content": "a"}'::jsonb, 'test1'::regclass::oid) v ;
col | name | def | status
---------+---------------------+-----------------------------------------------------------------------+---------
content | test1_content_check | CHECK ((length(content) > 0)) | valid
work | test1_check | CHECK ((((age >= 18) AND (work < 2)) OR ((age < 18) AND (work > 2)))) | null
age | test1_age_check | CHECK ((age > 18)) | invalid
age | test1_check | CHECK ((((age >= 18) AND (work < 2)) OR ((age < 18) AND (work > 2)))) | invalid
id | | | null