feat: Support LOG_FORMAT env variable (#2151)

test/test_log_format.py

@@ -0,0 +1,11 @@
+import pytest
+
+def test_log_format(docker_compose, nginxproxy):
+    r = nginxproxy.get("http://nginx-proxy.test/port")
+    assert r.status_code == 200
+    assert r.text == "answer from port 81\n"
+    sut_container = docker_compose.containers.get("sut")
+    docker_logs = sut_container.logs(stdout=True, stderr=True, stream=False, follow=False)
+    docker_logs = docker_logs.decode("utf-8").splitlines()
+    docker_logs = [line for line in docker_logs if "GET /port" in line]
+    assert "request_time=" in docker_logs[0]

test/test_log_format.yml

@@ -0,0 +1,15 @@
+web1:
+  image: web
+  expose:
+    - "81"
+  environment:
+    WEB_PORTS: 81
+    VIRTUAL_HOST: nginx-proxy.test
+
+sut:
+  container_name: sut
+  image: nginxproxy/nginx-proxy:test
+  volumes:
+    - /var/run/docker.sock:/tmp/docker.sock:ro
+  environment:
+    LOG_FORMAT: "$$remote_addr - $$remote_user [$$time_local] \"$$request\" $$status $$body_bytes_sent \"$$http_referer\" \"$$http_user_agent\" request_time=$$request_time $$upstream_response_time"