@bgschiller/slonik-migrator
v0.13.2
Published
database migration tool using slonik
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@bgschiller/slonik-migrator
This is a fork of @slonik/migrator, which only supports up to slonik@29 as of today
A cli migration tool for postgres, using slonik.
Motivation
There are already plenty of migration tools out there - but if you have an existing project that uses slonik, this will be the simplest to configure. Even if you don't, the setup required is minimal.
By default, the migration scripts it runs are plain .sql
files. No learning the quirks of an ORM, and how native postgres features map to API calls. It can also run .js
or .ts
files - but where possible, it's often preferable to keep it simple and stick to SQL.
This isn't technically a cli - it's a cli helper. Most node migration libraries are command-line utilities, which require a separate database.json
or config.json
file where you have to hard-code in your connection credentials. This library uses a different approach - it exposes a javascript function which you pass a slonik instance into. The javascript file you make that call in then becomes a runnable migration CLI. The migrations can be invoked programmatically from the same config.
Usage
npm install --save-dev @bgschiller/slonik-migrator
Then in a file called migrate.js
:
const { SlonikMigrator } = require("@bgschiller/slonik-migrator");
const { createPool } = require("slonik");
// in an existing slonik project, this would usually be setup in another module
const slonik = createPool(process.env.POSTGRES_CONNECTION_STRING); // e.g. 'postgresql://postgres:postgres@localhost:5433/postgres'
const migrator = new SlonikMigrator({
migrationsPath: __dirname + "/migrations",
migrationTableName: "migration",
slonik,
logger: SlonikMigrator.prettyLogger,
});
migrator.runAsCLI();
By calling runAsCLI()
, migrate.js
has now become a runnable cli script via node migrate.js
or just node migrate
:
node migrate create --name users.sql
This generates placeholder migration sql scripts in the directory specified by migrationsPath
called something like 2019-06-17T03-27.users.sql
and down/2019-06-17T03-27.users.sql
.
You can now edit the generated sql files to create table users(name text)
for the 'up' migration and drop table users
for the 'down' migration.
JavaScript and TypeScript migrations
These are expected to be modules with a required up
export and an optional down
export. Each of these functions will have an object passed to them with a slonik
instance, and a sql
tag function. You can see a javascript and a typescript example in the tests.
Note: if writing migrations in typescript, you will likely want to use a tool like ts-node to enable loading typescript modules. You can either add require('ts-node/register/transpile-only')
at the top of your migrate.js
file, or run node -r ts-node/register/transpile-only migrate ...
instead of node migrate ...
.
(Using ts-node/register/transpile-only
performs faster than ts-node/register
, and is safe to use if type-checking is performed separately).
Recommendation: where possible, it's better to use SQL migrations than JavaScript or TypeScript. They're more portable and less likely to have side-effects beyond the DB.
Running migrations
To run all "up" migrations:
node migrate up
The users
table will now have been created.
To revert the last migration:
node migrate down
The users
table will now have been dropped again.
More commands
To print the list of migrations that have already been applied:
node migrate executed
To print the list of migrations that are due to be applied:
node migrate pending
Controlling migrations
By default, node migrate down
reverts only the most recent migration.
It is also possible to migrate up or down "to" a specific migration. For example, if you have run migrations one.sql
, two.sql
, three.sql
and four.sql
, you can revert three.sql
and four.sql
by running node migrate down --to three.sql
. Note that the range is inclusive. To revert all migrations in one go, run node migrate down --to 0
. Note also that the migration names will usually contain a timestamp prefix, and can be listed with node migrate pending
or node migrate executed
.
Conversely, node migrate up
runs all up
migrations by default. To run only up to a certain migaton, run node migrate up --to two.sql
. This will run migrations one.sql
and two.sql
- again, the range is inclusive of the name.
See commands for more options, and examples to see how you can use the CLI.
Commands
usage: node migrate [-h] <command> ...
@bgschiller/slonik-migrator - PostgreSQL migration tool
Positional arguments:
<command>
up Applies pending migrations
down Revert migrations
pending Lists pending migrations
executed Lists executed migrations
create Create a migration file
repair Repair hashes in the migration table
Optional arguments:
-h, --help Show this help message and exit.
For detailed help about a specific command, use: node migrate <command> -h
up
usage: node migrate up [-h] [--to NAME] [--step COUNT] [--name MIGRATION]
[--rerun {THROW,SKIP,ALLOW}]
Performs all migrations. See --help for more options
Optional arguments:
-h, --help Show this help message and exit.
--to NAME All migrations up to and including this one should be
applied.
--step COUNT Run this many migrations. If not specified, all will
be applied.
--name MIGRATION Explicity declare migration name(s) to be applied.
--rerun {THROW,SKIP,ALLOW}
Specify what action should be taken when a migration
that has already been applied is passed to --name.
The default value is "THROW".
down
usage: node migrate down [-h] [--to NAME] [--step COUNT] [--name MIGRATION]
[--rerun {THROW,SKIP,ALLOW}]
Undoes previously-applied migrations. By default, undoes the most recent
migration only. Use --help for more options. Useful in development to start
from a clean slate. Use with care in production!
Optional arguments:
-h, --help Show this help message and exit.
--to NAME All migrations up to and including this one should be
reverted. Pass "0" to revert all.
--step COUNT Run this many migrations. If not specified, one will
be reverted.
--name MIGRATION Explicity declare migration name(s) to be reverted.
--rerun {THROW,SKIP,ALLOW}
Specify what action should be taken when a migration
that has already been reverted is passed to --name.
The default value is "THROW".
pending
usage: node migrate pending [-h] [--json]
Prints migrations returned by `umzug.pending()`. By default, prints migration
names one per line.
Optional arguments:
-h, --help Show this help message and exit.
--json Print pending migrations in a json format including names and
paths. This allows piping output to tools like jq. Without this
flag, the migration names will be printed one per line.
executed
usage: node migrate executed [-h] [--json]
Prints migrations returned by `umzug.executed()`. By default, prints
migration names one per line.
Optional arguments:
-h, --help Show this help message and exit.
--json Print executed migrations in a json format including names and
paths. This allows piping output to tools like jq. Without this
flag, the migration names will be printed one per line.
create
usage: node migrate create [-h] --name NAME [--prefix {TIMESTAMP,DATE,NONE}]
[--folder PATH] [--allow-extension EXTENSION]
[--skip-verify] [--allow-confusing-ordering]
Generates a placeholder migration file using a timestamp as a prefix. By
default, mimics the last existing migration, or guesses where to generate the
file if no migration exists yet.
Optional arguments:
-h, --help Show this help message and exit.
--name NAME The name of the migration file. e.g. my-migration.js,
my-migration.ts or my-migration.sql. Note - a prefix
will be added to this name, usually based on a
timestamp. See --prefix
--prefix {TIMESTAMP,DATE,NONE}
The prefix format for generated files. TIMESTAMP uses
a second-resolution timestamp, DATE uses a
day-resolution timestamp, and NONE removes the prefix
completely. The default value is "TIMESTAMP".
--folder PATH Path on the filesystem where the file should be
created. The new migration will be created as a
sibling of the last existing one if this is omitted.
--allow-extension EXTENSION
Allowable extension for created files. By default .js,
.ts and .sql files can be created. To create txt
file migrations, for example, you could use '--name
my-migration.txt --allow-extension .txt' This
parameter may alternatively be specified via the
UMZUG_ALLOW_EXTENSION environment variable.
--skip-verify By default, the generated file will be checked after
creation to make sure it is detected as a pending
migration. This catches problems like creation in the
wrong folder, or invalid naming conventions. This
flag bypasses that verification step.
--allow-confusing-ordering
By default, an error will be thrown if you try to
create a migration that will run before a migration
that already exists. This catches errors which can
cause problems if you change file naming conventions.
If you use a custom ordering system, you can disable
this behavior, but it's strongly recommended that you
don't! If you're unsure, just ignore this option.
repair
usage: node migrate repair [-h] [-d]
If, for any reason, the hashes are incorrectly stored in the database, you
can recompute them using this command. Note that due to a bug in
@bgschiller/slonik-migrator v0.8.X-v0.9-X the hashes were incorrectly calculated, so
this command is recommended after upgrading to v0.10.
Optional arguments:
-h, --help Show this help message and exit.
-d, --dry-run No changes are actually made
Examples
Assuming migrate.js
is a script setup something like:
const {SlonikMigrator} = require('@bgschiller/slonik-migrator')
const migrator = new SlonikMigrator(...)
migrator.runAsCLI()
Here are some ways you could use it:
ndoe migrate --help # shows help
node migrate up # runs all pending migrations
node migrate down # reverts the last-run migration
node migrate down --to 0 # reverts all migrations
node migrate up --to some-specific-migration.sql # runs all migrations up to and including some-specific-migration.sql
node migrate down --to some-other-migration.sql # reverts all migrations down to and including some-other-migration.sql
node migrate up --step 2 # runs the next two migrations
node migrate down --step 2 # reverts the two most recent migrations
node migrate up --name m1.sql --name m2.sql # runs only m1.sql and m2.sql. Throws if they aren't pending.
node migrate up --name m1.sql --name m2.sql --rerun ALLOW # runs m1.sql and m2.sql, even if they've already been executed
node migrate up --name m1.sql --name m2.sql --rerun SKIP # runs m1.sql and m2.sql, if they haven't already been executed. Skips if they have.
node migrate down --name m1.sql --name m2.sql # reverts only m1.sql and m2.sql. Throws if they haven't been executed.
node migrate down --name m1.sql --name m2.sql --rerun ALLOW # runs m1.sql and m2.sql, even if they haven't been executed yet.
node migrate down --name m1.sql --name m2.sql --rerun SKIP # runs m1.sql and m2.sql, if they have already been executed. Skips if they haven't.
node migrate up --help # shows help for `up`
node migrate down --help # shows help for `down`
node migrate create --name some-migration.sql # creates a new migration, prefixed with timestamp, in the migrations folder
node migrate pending # lists pending migrations
node migrate executed # lists executed migrations
node migrate repair --dry-run # logs which migrations are in need of a repair
node migrate repair # repairs them
Running programatically
To run migrations programmatically, you can import the migrator
object from another file. For example, in a lambda handler:
module.exports.handler = () => require("./migrate").up();
Or, you could write a script which seeds data in test environments:
import { migrator, slonik } from "./migrate";
import { sql } from "slonik";
export const seed = async () => {
const migrations = await migrator.up();
if (migrations.some((m) => m.file.endsWith(".users.sql"))) {
await slonik.query(sql`insert into users(name) values('foo')`);
}
};
Configuration
parameters for the SlonikMigrator
constructor:
| property | description | default value |
| -------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------- |
| slonik
| slonik database pool instance, created by createPool
. | N/A |
| migrationsPath
| path pointing to directory on filesystem where migration files will live. | N/A |
| migrationTableName
| the name for the table migrations information will be stored in. You can change this to avoid a clash with existing tables, or to conform with your team's naming standards. Set to an array to change the schema e.g. ['public', 'dbmigrations']
| N/A |
| logger
| how information about the migrations will be logged. You can set to console
to log raw objects to console, undefined
to prevent logs appearing at all, use SlonikMigrator.prettyLogger
or supply a custom logger. | undefined
|
SlonikMigrator.prettyLogger
logs all messages to console. Known events are prettified to strings, unknown events or unexpected message properties in known events are logged as objects.
Implementation
Under the hood, the library thinly wraps umzug with a custom slonik-based storage implementation.