Implement Migrations Component

[macielti]

Added

• Implement migrations component.

[Copilot]

Pull request overview

This PR implements a new migrations component for PostgreSQL database migrations using the Integrant lifecycle management framework. The component integrates with the pg2-migration library to execute database migrations during application startup.

Key Changes:

• Adds a new migrations component with Integrant lifecycle methods (init-key and halt-key!)
• Updates project dependencies and plugins to newer versions
• Bumps project version from 2.2.5 to 2.3.5

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 4 comments.

File	Description
src/postgresql_component/migrations.clj	Implements the new migrations component with init-key and halt-key! methods for Integrant lifecycle management
project.clj	Updates project version to 2.3.5, upgrades multiple dependencies (Clojure, Pedestal, pg2-core, integrant, etc.), and updates plugin versions
CHANGELOG.md	Documents the 2.3.5 release with the migrations component addition

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[Copilot]

The init-key method doesn't return the result of migrations/migrate-all. In Integrant, init-key should return a value that represents the initialized component, which is then passed to halt-key!. Currently, this method returns the result of migrate-all but doesn't store or track the migration state. Consider whether the component should return a map containing the configuration or migration result so it can be properly managed and potentially rolled back in halt-key! if needed.

Suggested change

	configuration (merge postgresql-config migrations-config)]
	(migrations/migrate-all configuration)))
	(defmethod ig/halt-key! ::postgresql-migrations
	[_ _]
	configuration (merge postgresql-config migrations-config)
	result (migrations/migrate-all configuration)]
	{:configuration configuration
	:result result}))
	(defmethod ig/halt-key! ::postgresql-migrations
	[_ component]

[Copilot]

The configuration retrieval from nested maps doesn't include nil checks or validation. If components, :config, :postgresql, or :postgresql-migrations are nil or missing, this will fail silently or produce confusing errors. Consider adding validation or error handling to provide clear error messages when required configuration is missing.

Suggested change

	(let [postgresql-config (-> components :config :postgresql)
	migrations-config (-> components :config :postgresql-migrations)
	configuration (merge postgresql-config migrations-config)]
	(migrations/migrate-all configuration)))
	(let [config (:config components)
	postgresql-config (:postgresql config)
	migrations-config (:postgresql-migrations config)]
	(when-not (map? config)
	(throw (ex-info "Missing or invalid :config for ::postgresql-migrations component"
	{:component ::postgresql-migrations
	:config config})))
	(when-not (map? postgresql-config)
	(throw (ex-info "Missing or invalid :postgresql configuration for ::postgresql-migrations"
	{:component ::postgresql-migrations
	:postgresql-config postgresql-config})))
	(when-not (map? migrations-config)
	(throw (ex-info "Missing or invalid :postgresql-migrations configuration for ::postgresql-migrations"
	{:component ::postgresql-migrations
	:migrations-config migrations-config})))
	(let [configuration (merge postgresql-config migrations-config)]
	(migrations/migrate-all configuration))))

[Copilot]

The new migrations component lacks test coverage. The repository has integration tests for the PostgreSQL component (postgresql_component_test.clj), but there are no tests for the migrations functionality. Consider adding integration tests to verify that the migrations component initializes correctly, applies migrations, and handles configuration properly.

[Copilot]

The migrations component requires the pg.migration.core namespace (from com.github.igrishaev/pg2-migration), but this dependency is only available in the :dev profile. Since migrations.clj is production code (in src/, not test/), the pg2-migration dependency should be moved from :dev :dependencies to the main :dependencies list to ensure it's available at runtime.

Suggested change

	[integrant.core :as ig]
	[pg.migration.core :as migrations]))
	(defmethod ig/init-key ::postgresql-migrations
	[_ {:keys [components]}]
	(log/info :starting ::postgresql-migrations)
	(let [postgresql-config (-> components :config :postgresql)
	migrations-config (-> components :config :postgresql-migrations)
	configuration (merge postgresql-config migrations-config)]
	(migrations/migrate-all configuration)))
	[integrant.core :as ig]))
	(defmethod ig/init-key ::postgresql-migrations
	[_ {:keys [components]}]
	(log/info :starting ::postgresql-migrations)
	(let [postgresql-config (-> components :config :postgresql)
	migrations-config (-> components :config :postgresql-migrations)
	configuration (merge postgresql-config migrations-config)
	migrate-all (or (some-> 'pg.migration.core/migrate-all
	clojure.core/requiring-resolve)
	(throw (ex-info "pg.migration.core/migrate-all not found; ensure com.github.igrishaev/pg2-migration is on the classpath"
	{:component ::postgresql-migrations})))]
	(migrate-all configuration)))