Class DatabaseMigrator

Creates or upgrades the schema at start, before the server accepts requests, in write-ahead log mode so reads do not block writes; and flushes the database at stop.

Inheritance

object

DatabaseMigrator

Implements

IHostedService

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: Uniform.Matrix.Server.Storage

Assembly: Uniform.Matrix.Server.dll

Syntax

public sealed class DatabaseMigrator : IHostedService

Remarks

It holds the DataDirectoryLock, so no other process uses the database meanwhile; a migration lock that a process left behind when it died is therefore removed instead of waited for, as EF Core would wait forever.

Constructors

DatabaseMigrator(IDbContextFactory<ServerDbContext>, DataDirectoryLock, ILogger<DatabaseMigrator>)

Use contexts for the database, which directoryLock keeps to this process.

Declaration

public DatabaseMigrator(IDbContextFactory<ServerDbContext> contexts, DataDirectoryLock directoryLock, ILogger<DatabaseMigrator> logger)

Parameters

Type	Name	Description
IDbContextFactory<ServerDbContext>	contexts	The database.
DataDirectoryLock	directoryLock	The lock of the data directory; taken here so that the host keeps it until disposed.
ILogger<DatabaseMigrator>	logger	Log of leftover locks and the stop.

Methods

StartAsync(CancellationToken)

Remove a leftover migration lock, switch to the write-ahead log, and apply pending migrations; throw with advice when the database has tables the migration history does not know.

Declaration

public Task StartAsync(CancellationToken cancellationToken)

Parameters

Type	Name	Description
CancellationToken	cancellationToken

Returns

Type	Description
Task

StopAsync(CancellationToken)

Write the write-ahead log into the database and close its pooled connections, so that the files are complete when the process ends; other databases of the process, e.g. of other servers in tests, keep theirs.

Declaration

public Task StopAsync(CancellationToken cancellationToken)

Parameters

Type	Name	Description
CancellationToken	cancellationToken

Returns

Type	Description
Task

Implements

IHostedService