status(host): add monitoring for ACME DNS

resources/external/status/docker_compose/compose.yaml.j2

@@ -25,6 +25,7 @@ services:
       - "POSTGRES_USER=gatus"
       - "POSTGRES_PASSWORD={{ secret__gatus_db_password }}"
       - "MATRIX_ACCESS_TOKEN={{ secret__gatus_matrix_access_token }}"
+      - "ACME_DNS_UPDATE_TEST_X_API_KEY={{ secret__gatus_acme_dns_update_test_x_api_key }}"
     volumes:
       - ./configs:/config
     networks:

resources/external/status/docker_compose/config/services-chaosknoten.yaml

@@ -11,6 +11,45 @@ services-chaosknoten-defaults: &services_chaosknoten_defaults
       send-on-resolved: true
 
 endpoints:
+  - name: ACME DNS (main page/login)
+    url: "https://acmedns.hamburg.ccc.de"
+    <<: *services_chaosknoten_defaults
+    conditions:
+      - "[STATUS] == 200"
+      - "[CERTIFICATE_EXPIRATION] > 48h"
+      - "[BODY] == pat(*OAuth2 Proxy*)"
+
+  - name: ACME DNS (update endpoint)
+    url: "https://acmedns.hamburg.ccc.de/update"
+    <<: *services_chaosknoten_defaults
+    method: POST
+    # acme-dns validates that the value for the txt is 43 characters long.
+    # https://github.com/joohoi/acme-dns/blob/b7a0a8a7bcef39f6158dd596fe716594a170d362/validation.go#L34-L41
+    body: |
+      {
+        "subdomain": "c621ef99-3da9-4ef6-a152-3a82b9b720f8",
+        "txt": "________________gatus_test_________________"
+      }
+    headers:
+      X-Api-User: "b897048a-1526-42aa-bc24-e4dfd654b722"
+      X-Api-Key: "${ACME_DNS_UPDATE_TEST_X_API_KEY}"
+    conditions:
+      - "[STATUS] == 200"
+      - "[CERTIFICATE_EXPIRATION] > 48h"
+      - "[BODY].txt == ________________gatus_test_________________"
+
+  - name: ACME DNS (DNS)
+    url: "acmedns.hosts.hamburg.ccc.de"
+    <<: *services_chaosknoten_defaults
+    dns:
+      query-name: "c621ef99-3da9-4ef6-a152-3a82b9b720f8.auth.acmedns.hamburg.ccc.de"
+      query-type: "TXT"
+    conditions:
+      - "[DNS_RCODE] == NOERROR"
+      # error: query type is not supported yet
+      # apparently TXT records aren't supported yet.
+      # - "[BODY] == ________________gatus_test_________________"
+
   - name: CCCHH ID/Keycloak (main page/account console)
     url: "https://id.hamburg.ccc.de/"
     <<: *services_chaosknoten_defaults