Deucalion

Minimal project for systems monitoring. When Grafana + Prometheus is overkill.

This is not a "Status Page" project. There is no intention to add alerts, incident histories, push notifications, or CRUD UIs to configure everything.

Just put up a simple configuration file, start the service, and you are done.

Usage

For a quick start:

# docker-compose.yaml
version: "3.9"

services:
  deucalion:
    user: root
    container_name: deucalion
    image: ghcr.io/fdcastel/deucalion:latest
    ports:
     - 80:8080
    environment:
      - DEUCALION__PAGETITLE=Deucalion status
    volumes:
      - ./example.yaml:/app/deucalion.yaml
      - ./data/:/storage/

# example.yaml
monitors:
  ping-example:
    !ping
    host: cloudflare.com
    intervalWhenUp: 00:00:03
    group: Cloudflare

  tcp-example:
    !tcp
    host: cloudflare.com
    port: 443
    intervalWhenUp: 00:00:03
    group: Cloudflare

  dns-example:
    !dns
    host: google.com
    recordType: A
    resolver: 1.1.1.1:53
    intervalWhenUp: 00:00:03
    group: Google

  http-example:
    !http
    url: https://google.com
    expectedStatusCode: 200
    expectedResponseBodyPattern: .*
    ignoreCertificateErrors: true
    intervalWhenUp: 00:00:03
    group: Google

Development notes

Project guidelines:

• Configuration files over CRUD forms
• Hexagonal Architecture
• K.I.S.S.
• Do One Thing And Do It Well: Not a "Status Page" (with incidents, justifications, etc)

Projects overview:

• Deucalion.Core: Base types and events shared between servers and clients.
• Deucalion.Application: Core engine and configuration.
• Deucalion.Network: Base network monitors.
• Deucalion.Storage: Persistence and statistics.
• Deucalion.Api: Server-side Asp.Net Web Api application.
• Deucalion.Service: Service Host for Deucalion.Api. Can run as a Service on Windows.
• deucalion-ui: Client-side React application.
• Deucalion.Tests: xUnit tests.
• Deucalion.Cli: Sample command-line SignalR client.

How to debug

Using Visual Studio 2022

Open Deucalion.sln with Visual Studio 2022.

Start both Deucalion.Api and deucalion-ui projects. You may set multiple startup projects for this.

Do not use Deucalion.Service for debugging. It uses a static (pre-built) version of UI (you need to run Invoke-Build Build first).

Using Visual Studio Code

Run

Invoke-Build Dev

This will start both Deucalion.Api and deucalion-ui projects in development mode. Any source file changes will be detected and reloaded.

Logging

In Development environment the log level for Deucalion.Api namespace is Debug. This generates a log entry for each message received from EngineBackgroundService.

For Production environments the log level is Information (the default). To change this, you can run the application with

--Logging:LogLevel:Deucalion=Debug

in command-line. Or change the appropriate value in appsettings.json.

How to build

Install Invoke-Build.

Invoke-Build or Invoke-Build build will put all artifacts in ./publish folder.

Invoke-Build test will build and start a production version using ./deucalion-sample.yaml configuration.