The Runner

At the heart of migrations is the MigrationRunner. The migration runner scans all provided assemblies for classes deriving from the Migration base class and then orders them according to their migration attribute value.

After each migration is executed, a MigrationRecord is inserted into your database, unless no journaling is set. This ensures that the next time the runner is executed, previously completed migrations are not executed again. When a migration is rolled back the MigrationRecord is removed.

You can modify the runner options by passing an action to the .AddCouchbaseMigrations call:

// In Startup.cs
public void ConfigureServices( IServiceCollection services )
{
    services.AddCouchbaseMigrations( options =>
    {
        // Configure migration options
        options.Direction = Direction.Down;
    });
}

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, null,null, true,"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.AddCouchbaseMigrations( options =>
    {
        // Configure to only run development migrations
         options.Profiles = new[] { "development" } };
    });
}

A migration may belong to multiple profiles.

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

This migration will run if either the development or the stating profile is specified in MigrationOptions.

The Record Store

Hyperbee Migrations currently supports Couchbase, MongoDB & Postgres databases but it can easily be extended. The steps are:

1. Derive from IMigrationRecordStore
2. Derive from MigrationOptions to add any store specific configuration
3. Implement ServiceCollectionExtensions to register your implementation

See the one of the current implementations for reference.

Configure Local Solution

To run the migration solution you will need to add some local configuration.

appsettings.developer.json

{
  "Couchbase": {
    "ConnectionString": "couchbase://localhost"
  }
}

Manage User Secrets

{
  "Couchbase:UserName": "Administrator",
  "Couchbase:Password": "_YOUR_PASSWORD_"
}

Using Sample Runners

Currently there is are sample runners for each of the database providers. These provider a simple console app that can be run using a command line or built into a docker image.

Running From The Command Line

Once installed as a dotnet tool, the runner can be run from the command line. The runner expects, and will use settings from the appSettings.json in the execution folder. Arguments can also be provided from the command line.

Command Line Options

Switch	Alias	Description
-f	–file	From Paths Array
-a	–assembly	From Assemblies Array
-p	–profile	Profiles Array
-b	–bucket	Bucket Name
-s	–scope	Scope Name
-c	–collection	Collection Name
-usr	–user	Database User
-pwd	–password	Database Password
-cs	–connection	Database Connection String

Runtime Configuration

{
  "Couchbase": {
    "ConnectionString": "__CONNECTION_STRING_HERE__",
    "UserName": "__SECRET_HERE__",
    "Password": "__SECRET_HERE__",
    "MaxConnectionLimit": 20
  },
  "Migrations": {
    "BucketName": "hyperbee",
    "ScopeName": "migrations",
    "CollectionName": "ledger",
    "Lock": {
      "Enabled": false,
      "Name": "migration-runner-mutex",
      "MaxLifetime": 3600,
      "ExpireInterval": 300,
      "RenewInterval": 120
    },
    "FromPaths": [
      "c:\\my-migration-assembly.dll"
    ],
    "FromAssemblies": [
    ]
  },
  "Serilog": {
    "MinimumLevel": {
      "Default": "Debug",
      "Override": {
        "Couchbase": "Warning",
        "Microsoft": "Warning",
        "Microsoft.Hosting.Lifetime": "Information",
        "System": "Warning"
      }
    }
  }
}