Add support for CORS in HAProxy stats dashboard

- Introduced `HAPROXY_STATS_CORS_ORIGIN` environment variable for enabling CORS in HAProxy stats.
- Updated HAProxy configuration template to handle CORS preflight and response headers.
- Added tests for static configuration mode with CORS enabled.
- Updated documentation to include new CORS configuration details and examples.

tests/expected/static-cors.txt

@@ -0,0 +1,77 @@
+global
+    log stdout  format raw  local0  info
+    maxconn 2000
+    tune.ssl.default-dh-param 2048
+
+    # intermediate configuration
+    ssl-default-bind-ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384
+    ssl-default-bind-ciphersuites TLS_AES_128_GCM_SHA256:TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256
+    ssl-default-bind-options prefer-client-ciphers no-sslv3 no-tlsv10 no-tlsv11 no-tls-tickets
+
+    ssl-default-server-ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384
+    ssl-default-server-ciphersuites TLS_AES_128_GCM_SHA256:TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256
+    ssl-default-server-options no-sslv3 no-tlsv10 no-tlsv11 no-tls-tickets
+
+    ssl-dh-param-file /etc/easyhaproxy/haproxy/dhparam
+
+defaults
+    log global
+    unique-id-format %{+X}o\ %ci:%cp_%fi:%fp_%Ts_%rt:%pid
+    unique-id-header X-Edge-Request-ID
+    option httplog
+
+    timeout connect    3s
+    timeout client    10s
+    timeout server    10m
+
+
+frontend stats
+    bind *:1936
+    mode http
+    http-request use-service prometheus-exporter if { path /metrics }
+    # CORS for stats dashboard (only for configured origin)
+    acl from_ui hdr(Origin) -i http://localhost:3000
+    acl preflight method OPTIONS
+
+    # Preflight response
+    http-request return status 204 hdr "Access-Control-Allow-Origin" "%[req.hdr(Origin)]" hdr "Access-Control-Allow-Methods" "GET, OPTIONS" hdr "Access-Control-Allow-Headers" "Authorization, Content-Type" hdr "Access-Control-Max-Age" "86400" hdr "Vary" "Origin" if from_ui preflight
+
+    # Actual response headers
+    http-after-response set-header Access-Control-Allow-Origin "http://localhost:3000"
+    http-after-response set-header Access-Control-Allow-Methods "GET, OPTIONS"
+    http-after-response set-header Access-Control-Allow-Headers "Authorization, Content-Type"
+    http-after-response set-header Access-Control-Expose-Headers "X-Request-ID"
+    http-after-response set-header Vary "Origin"
+
+    stats enable
+    stats hide-version
+    stats realm Haproxy\ Statistics
+    stats uri /
+    stats auth admin:test123
+    default_backend srv_stats
+
+backend srv_stats
+    mode http
+    server Local 127.0.0.1:1936
+
+frontend http_in_80
+    bind *:80
+    mode http
+
+    acl is_rule_host1_com_br_80_1 hdr(host) -i host1.com.br
+    acl is_rule_host1_com_br_80_2 hdr(host) -i host1.com.br:80
+    use_backend srv_host1_com_br_80 if is_rule_host1_com_br_80_1 OR is_rule_host1_com_br_80_2
+
+backend srv_host1_com_br_80
+    balance roundrobin
+    mode http
+    option forwardfor
+    http-request set-header X-Forwarded-Port %[dst_port]
+    http-request add-header X-Forwarded-Proto https if { ssl_fc }
+    http-request set-header X-Forwarded-Host %[req.hdr(Host)]
+    http-request set-header X-Request-ID %[uuid()]
+    server srv-0 container:5000 check weight 1
+
+backend certbot_backend
+    mode http
+    server certbot 127.0.0.1:2080

tests/fixtures/static_cors.yml

@@ -0,0 +1,11 @@
+stats:
+  username: admin
+  password: test123
+  port: 1936
+  cors_origin: http://localhost:3000
+
+customerrors: false
+
+containers:
+  "host1.com.br:80":
+    ip: ["container:5000"]

tests/test_containerenv.py

@@ -149,8 +149,8 @@ def test_container_env_stats_password():
                    "stats": {
                        "username": "admin",
                        "password": "xyz",
-                       "port": "1936"
-
+                       "port": "1936",
+                       "cors_origin": ""
                    },
                    "logLevel": {
                        "easyhaproxy": Functions.DEBUG,
@@ -191,7 +191,8 @@ def test_container_env_stats_password_2():
                    "stats": {
                        "username": "abc",
                        "password": "xyz",
-                       "port": "2101"
+                       "port": "2101",
+                       "cors_origin": ""
                    },
                    "logLevel": {
                        "easyhaproxy": Functions.DEBUG,

tests/test_static.py

@@ -90,4 +90,36 @@ def test_processor_static_multiple_domains_same_container():
     # Both should point to the same container
     assert haproxy_cfg.count('server srv-0 webapp:8080') == 2
 
+
+def test_processor_static_with_cors():
+    """Test that CORS configuration is properly generated when cors_origin is set"""
+    ProcessorInterface.static_file = os.path.join(
+        os.path.dirname(os.path.realpath(__file__)),
+        "./fixtures/static_cors.yml"
+    )
+    static = ProcessorInterface.factory(ProcessorInterface.STATIC)
+
+    haproxy_cfg = static.get_haproxy_conf()
+
+    # Verify CORS configuration is present in stats frontend
+    assert '# CORS for stats dashboard (only for configured origin)' in haproxy_cfg
+    assert 'acl from_ui hdr(Origin) -i http://localhost:3000' in haproxy_cfg
+    assert 'acl preflight method OPTIONS' in haproxy_cfg
+
+    # Verify preflight response
+    assert 'http-request return status 204' in haproxy_cfg
+    assert 'hdr "Access-Control-Allow-Origin"' in haproxy_cfg
+    assert 'hdr "Access-Control-Allow-Methods" "GET, OPTIONS"' in haproxy_cfg
+    assert 'hdr "Access-Control-Allow-Headers" "Authorization, Content-Type"' in haproxy_cfg
+    assert 'if from_ui preflight' in haproxy_cfg
+
+    # Verify actual response headers (no ACL condition in response phase)
+    assert 'http-after-response set-header Access-Control-Allow-Origin "http://localhost:3000"' in haproxy_cfg
+    assert 'http-after-response set-header Access-Control-Expose-Headers "X-Request-ID"' in haproxy_cfg
+    assert 'http-after-response set-header Vary "Origin"' in haproxy_cfg
+
+    # Verify the full config matches expected
+    assert haproxy_cfg == Functions.load(
+        os.path.join(os.path.dirname(os.path.realpath(__file__)), "./expected/static-cors.txt"))
+
 # test_processor_static()