Seq HTTP API Client

This library includes:

• C# representations of the entities exposed by the Seq HTTP API
• Helper classes for interacting with the API

It's useful for querying events and working with configuration data - everything you can do using the Seq web UI, you can do programmatically via the API.

If you want to write events to Seq, use one of the logging framework clients, such as Serilog.Sinks.Seq or NLog.Targets.Seq instead.

Getting started

Install from NuGet:

dotnet add package Seq.Api

Create a SeqConnection with your server URL:

varconnection=newSeqConnection("http://localhost:5341");

Navigate the "resource groups" exposed as properties of the connnection:

varinstalledApps=awaitconnection.Apps.ListAsync();

To authenticate, the SeqConnection constructor accepts an apiKey parameter (make sure the API key permits user-level access) or, if you want to log in with personal credentials you can await connection.Users.LoginAsync(username, password).

For a more complete example, see the seq-tail app included in the source.

Creating entities

The Seq API provides a /template resource for each resource group that provides a new instance of the resource with defaults populated. The API client uses this pattern when creating new entities:

varsignal=awaitconnection.Signals.TemplateAsync();signal.Title="Signal 123";awaitconnection.Signals.AddAsync(signal);

See the signal-copy app for an example of this pattern in action.

Reading events

Seq internally limits the resources a query is allowed to consume. The query methods on SeqConnection.Events include a status with each result set - a Partial status indicates that further results must be retrieved.

The snippet below demonstrates lazily enumerating through results to retrieve the complete set.

varresultSet=connection.Events.EnumerateAsync(filter:"Environment = 'Test'",render:true,count:1000);awaitforeach(varevtinresultSet)Console.WriteLine(evt.RenderedMessage);

All methods that retrieve events require a count. The API client defaults this value to 30 if not specified.

Streaming events

Seq provides live streaming of events matching a filter and/or set of signals.

varfilter="@Level = 'Error'";awaitforeach(varevtinconnection.Events.StreamAsync<JObject>(filter:filter,clef:true)){varlogEvent=LogEventReader.ReadFromString(evt);Log.Write(logEvent);}

Events.StreamAsync() method returns IAsyncEnumerable<T> over a WebSocket. The enumerator will keep producing events until either it's disposed, or the server is shut down.

Seq streams the events in compact JSON format, which the Seq API client library can deserialize into JSON.NET JObjects for consumption.

Serilog.Formatting.Compact.Reader provides the LogEventReader class used above to turn these documents back into Serilog LogEvents. Having the events represented in Serilog’s object model means they can be passed back into a logging pipeline, as performed above using Log.Write().

Working with the basic client

The SeqApiClient class implements the low level interactions with the API's entities and links. It's one step up from System.Net.HttpClient - you may be able to use it in cases not supported by the high-level wrapper.

Create a SeqApiClient with your server URL:

varclient=newSeqApiClient("http://localhost:5341");

Get the root resource and use it to retrieve one or more of the resource groups:

varroot=awaitclient.GetRootAsync();varevents=awaitclient.GetAsync<ResourceGroup>(root,"EventsResources");

(Available resource groups, like Events, Users and so-on, can be seen in the root document's Links collection.)

Use the client to navigate links from entity to entity:

varmatched=awaitclient.ListAsync<EventEntity>(events,"Items",newDictionary<string,object>{{"count",10},{"render",true}});foreach(varmatchinmatched)Console.WriteLine(match.RenderedMessage);

Package versioning

This package does not follow the SemVer rule of major version increments for breaking changes. Instead, the package version tracks the Seq version it supports.