Mini monitor

This is a small a standalone status page for multiple service checks. (Like Nagios just much dumber.)

Build

Simply run the following command:

$ go build src/cmd/monitor/monitor.go

Run

$ monitor -listen :8080 -config config.json

By default the web UI will listen on localhost:8080.

You could open the following URLs in your browser:

• / - HTML web UI
• /api - JSON based status endpoint

Web UI example:

JSON response structure:

{
   "checks":{
      "docker-alpine":false,
      "test1":true,
      "test3":true,
      "test4":false
   }
}

Configuration

Put a json file with a similar content like:

{
  "checkTime": "5s",
  "configs": [
    {
      "name": "unique-config-name",
      "type": "debug",
      "config": {
        "testKey": "testVal"
      }
    },
    ...
  ]
}

Here the fields are the following:

• name is the modules name you'd like to use, it should be unique in the config
• type should be the checkers type, see the available ones below
• config is the given modules configuration

Available checkers

Debug

Obviously for debugging purpose.

Type definition: debug

Possible keys:

• loadFail (bool) triggers an error on module load
• checkFail (bool) tiggers and error at the check call

Docker

Basic docker container checker using the docker ps command.

Type definition: docker

Possible keys:

• id (string) is the container id check
• nameRegex (string) is the regular expression to match on a container's name
• imageRegex (string) is the regular expression to match on an image's name
• debug (bool) is for help the regular expression debugging

They are all optional and will match these fields to the docker ps output, but be careful if there are multiple matches it'll grab and check the first match only! (Use the id if you'd like to guarantee to have a single match or use unique container names.)

HTTP

Type definition: http

Possible keys:

• method (string) is the HTTP method to use (auto converted to upper-case)
• url (string) is the HTTP URL to call
• body (string) is the HTTP request body
• headers (map[string]string) are the request headers in a key - value format
• expectedCode (int) is the HTTP response code for the successful check

The method, url and expectedCode are required.

Example config:

{
  "name": "test-http",
   "type": "http",
   "config": {
     "method": "get",
     "url": "http://192.168.0.100:3001/",
     "headers": {
       "Authorization": "Bearer testToken"
     },
     "expectedCode": 200
   }
 }