Hyperbee.Migrations.Providers.Postgres 2.0.0

Hyperbee Migrations Postgres Provider

Welcome to Hyperbee.Migrations.Providers.Postgres, an extension to the foundational Hyperbee.Migrations library. This extension is specifically designed to incorporate support for Postgres.

Introduction

The Hyperbee.Migrations.Providers.Postgres library is an tool for developers seeking to perform database migrations in a Postgres environment using the Hyperbee.Migrations library. This library furnishes a comprehensive suite of tools and functionalities that integrate effortlessly with Hyperbee.Migrations, thereby enabling developers to harness the robust capabilities of Postgres in their applications.

The Hyperbee.Migrations.Providers.Postgres library is equipped to assist developers in creating, updating, and managing their Postgres databases. With the aid of this library, developers can concentrate their efforts on the development of their application, while the library handles the intricacies of database management.

We are committed to continuous improvement and feature enhancement. We appreciate your interest and look forward to your valuable feedback.

Please see Hyperbee Migrations' Read Me for non-database specific usage.

Concepts

Every migration has several elements you need to be aware of.

• You can create a StartMethod method that resolves to Task <bool>, in order to tell the runner when to start.
• You can create a StopMethod method that resolves to Task <bool>, in order to tell the runner when to stop.
• You can set whether or not you want to journal the migration.

Configuration

Add Postgres Services

// In Startup.cs
public void ConfigureServices(IServiceCollection services)
{
    // Configure Postgres
    services.AddNpgsqlDataSource( connectionString );

    // Add the MigrationRunner
    services.AddPostgresMigrations(...);
}

public void Configure(IApplicationBuilder app, ...)
{
    // Run pending migrations.
    var migrationService = app.ApplicationServices.GetRequiredService<MigrationRunner>();
    migrationService.Run();
}

Preventing simultaneous migrations

By default, Hyperbee Migrations prevents parallel migration runner execution. If you have 2 instances of your app running, and both try to run migrations, Hyperbee Migrations will prevent the second instance from running migrations and will log a warning.

Hyperbee Migrations accomplishes this by using a distributed lock at the database layer. The default implementation is based on the provider and uses a timeout and an auto-renewal interval to prevent orphaned locks.

If you want to change this behavior you can override the default options:

services.AddPostgresDBMigrations( options =>
{
    // Locking is on by default. Set to false to allow simultaneous runners - but don't be that guy.
    options.LockingEnabled = false;

    // You can change locking behavior. Defaults shown.
    options.LockMaxLifetime = TimeSpan.FromMinutes( 1 );         // max time-to-live
    options.LockName = "ledger"
});

Migrations

Hyperbee Migrations relies on dependency injection to pass services to your migration.

[Migration(1)]
public class MyMigration : Migration
{
	private IClusterProvider _clusterProvider;
    private ILogger _logger;

	// Injected services registered with the container
	public MyMigration( IClusterProvider clusterProvider, ILogger<MyMigration> logger )
	{
        _clusterProvider = clusterProvider;
		_logger = logger;
	}

	public async override Task UpAsync( CancellationToken cancellationToken = default )
	{
		// do something with clusterProvider
	}
}

Dependency Injection

The Postgres provider also provides a PostgresResourceRunner<MyMigration> that adds helpful functionality when using embedded resources.

• SqlFromAsync runs sql statements and can do any sort of updates supported by Postgres
• AllSqlFromAsync runs all the embedded resources with the resource named matching the Migration. See 1000-Initial as an example
• StartMethod determines when the migration should start (optional)
• StopMethod determines when the migration should stop (optional)
• false determines if you want to journal (default = true)

[Migration(1, "StartMethod", "StopMethod", false)]
public class MyMigration : Migration
{
    private readonly PostgresResourceRunner<MyMigration> _resourceRunner;

    public CreateInitialBuckets( PostgresResourceRunner<MyMigration> resourceRunner )
    {
        _resourceRunner = resourceRunner;
    }

    public override async Task UpAsync( CancellationToken cancellationToken = default )
    {
        // run a `resource` migration to create initial state.
        await resourceRunner.SqlFromAsync( [
            "1-MyMigration.sql"
        ], cancellationToken );
    }

     public Task<bool> StartMethod()
    {
      //create process here        
    }
    
    public Task<bool> StopMethod()
    {
      //create process here    
    }
}

Profiles

There are times when you may want to scope migrations to specific environments. To allow this Hyperbee Migrations supports profiles. For instance, some migrations might only run during development. By decorating your migration with the profile of "development" and setting options to include only that profile, you can control which migrations run in which environments.

[Migration(3, "development")]
public class DevelopmentOnlyMigration : Migration
{
    public async override Task UpAsync( CancellationToken cancellationToken = default )
    {
        // do something nice for local developers
    }
}

...

// In Startup.cs
public void ConfigureServices( IServiceCollection services )
{
    services.AddPostgresMigrations( options =>
    {
        // Configure to only run development migrations
         options.Profiles = new[] { "development" } };
    });
}

A migration may belong to multiple profiles.

[Migration(3, "development", "staging")]
public class TargetedMigration : Migration
{
    // ...
}

Cron Settings

[Migration(3, "StartMethod", "StopMethod")]
public class DevelopmentOnlyMigration : Migration
{
    public async override Task UpAsync( CancellationToken cancellationToken = default )
    {
        // do something nice for local developers
    }

     public async Task<bool> StartMethod()
    {
        var helper = new MigrationCronHelper();
        var results = await helper.CronDelayAsync( "* * * * *" );
        return results;       
    }

    public Task<bool> StopMethod()
    {
       var helper = new MigrationCronHelper();
       var results = await helper.CronDelayAsync( "4 * * * *" );
       return results;   
    }
}

Journaling

Journaling is a bool indicator. Null indicates there are no start or stop methods.

[Migration(3, null, null, false)]
public class DevelopmentOnlyMigration : Migration
{
    public async override Task UpAsync( CancellationToken cancellationToken = default )
    {
        // do something nice for local developers
    }
}