PagerDuty Statusページの移行に対応する

{
  "ends_at": null,
  "href": "https://subdomain.trust.pagerduty.com/incident_details/PXXXXXX",
  "message": "We are currently working on the issue.",
  "next_update_ms": 900000,
  "post_type": "incident",
  "reported_at": "2023-05-15T20:47:12Z",
  "services": [
    {
      "service_name": "Checkout",
      "severity": "minor"
    }
  ],
  "severity": "minor",
  "starts_at": null,
  "status": "investigating",
  "status_page": "Acme Corp",
  "title": "Checkout is temporarily unavailable"
}

require 'json'
require 'net/http'
require 'uri'

class Handler
  class << self
    def process(event:, context:)
      puts(event)

      payload = JSON.parse(event['body'])

      case payload['post_type'].to_sym
      when :maintenance, :incident
        handler = \
          case payload['status'].to_sym
          when :resolved, :completed
            ApiClient::Alert::Closer
          else
            ApiClient::Alert::Creater
          end

        handler.new(payload).call
      end

      :ok
    end
  end
end

module ApiClient
  module Alert
    class Base
      BASE_URL = 'https://api.opsgenie.com/'; private_constant :BASE_URL
      API_KEY = ENV.fetch('OPSGENIE_API_KEY'); private_constant :API_KEY

      def initialize(payload)
        @payload = payload

        @incident_id = payload['href'].split('/').last

        @service_names = payload['services'].map{|x| x['service_name']}.join(', ')
      end

      def call
        res = Net::HTTP.post(url, data.to_json, {
          'Authorization': "GenieKey #{API_KEY}",
          'Content-Type': 'application/json'
        })

        unless res.code == '202'
          puts(
            fail_log(res)
          )
        end
      end

      private

      def url
        @url ||= URI.join(BASE_URL, path)
      end

      def path
        raise NotImplementedError
      end

      def data
        raise NotImplementedError
      end

      def lookup(key)
        v = @payload[key.to_s]

        v.nil? ? '<null>' : v.to_s
      end

      def fail_log(res)
        JSON.generate({
          url: url.to_s,
          status: res.code,
          message: res.body
        })
      end
    end

    class Creater < Base
      private

      def path
        '/v2/alerts'
      end

      def data
        {
          message: lookup(:title),
          description: lookup(:message),
          details: {
            ends_at: lookup(:ends_at),
            href: lookup(:href),
            incident_id: @incident_id,
            next_update_ms: lookup(:next_update_ms),
            post_type: lookup(:post_type),
            reported_at: lookup(:reported_at),
            service: @service_names,
            severity: lookup(:severity),
            starts_at: lookup(:starts_at),
            status: lookup(:status),
            status_page: lookup(:status_page)
          }
        }
      end
    end

    class Closer < Base
      private

      def path
        "/v2/alerts/#{@incident_id}/close?identifierType=alias"
      end

      def data
        {
          user: lookup(:status_page),
          source: lookup(:status_page),
          note: lookup(:message)
        }
      end
    end
  end
end