Serilog.Sinks.AzureDocumentDB

A Serilog sink that writes to Azure DocumentDB.

Getting started

Install Serilog.Sinks.AzureDocumentDB from NuGet

Install-Package Serilog.Sinks.AzureDocumentDB

Configure logger by calling WriteTo.AzureDocumentDB(<uri>, <key>)

var logger = new LoggerConfiguration()
    .WriteTo.AzureDocumentDB(<uri>, <secure-key>)
    .CreateLogger();

TTL (Time-to-live)

Azure DocumentDB is making easier to prune old data with support of Time To Live (TTL) so does Sink. AzureDocumentDB Sink offers TTL at two levels.

Enable TTL at collection level.

Sink supports TTL at collection level, if collection does not already exist.

To enable TTL at collection level, set timeToLive parameter in code.

.WriteTo.AzureDocumentDB(<uri>, <secure-key>, timeToLive: TimeSpan.FromDays(7))

If collection in DocumentDB doesn't exists, it will create one and set TTL on collection level causing all logs messages purge older than 7 days.

Enable TTL at inidividual log message level.

Sink do support TTL at individual message level. This allows developer to retian log message of high importance longer than of lesser importance.

logger.Information("This message will expire and purge automatically after {@_ttl} seconds", 60);

logger.Information("Log message will be retained for 30 days {@_ttl}", 2592000); // 30*24*60*60

logger.Information("Messages of high importance will never expire {@_ttl}", -1); 

See TTL behavior in DocumentDB documentation for in depth explianation.

Note: {@_ttl} is a reserved expression for TTL.

XML configuration

To use the AzureDocumentDB sink with the Serilog.Settings.AppSettings package, first install that package if you haven't already done so:

Install-Package Serilog.Settings.AppSettings

In your code, call ReadFrom.AppSettings()

var logger = new LoggerConfiguration()
    .ReadFrom.AppSettings()
    .CreateLogger();

In your application's App.config or Web.config file, specify the DocumentDB sink assembly and required endpointUrl and authorizationKey parameters under the <appSettings>

<appSettings>
  <add key="serilog:using:AzureDocumentDB" value="Serilog.Sinks.AzureDocumentDB" />
  <add key="serilog:write-to:AzureDocumentDB.endpointUrl" value="https://****.documents.azure.com:443" />
  <add key="serilog:write-to:AzureDocumentDB.authorizationKey" value="****" />
    
  <!-- Liefspan of log messages in DocumentDB in seconds, leave empty to disable expiration. -->
  <add key="serilog:write-to:AzureDocumentDB.timeToLive" value="60" />
</appSettings>

Performance

Sink buffers log internally and flush to Azure DocumentDB in batches using dedicated thread. However, it highly depends on type of Azure DocumentDB subscription you have.