set flask app instances to log json in k8s clusters

sample-server/Procfile

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+uwsgi: LOG_JSON=true DEBUG=false uwsgi --ini sample-server/uwsgi.ini
+nginx: nginx -c $(pwd)/sample-server/nginx.conf

sample-server/nginx.conf

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+worker_processes  1;
+
+daemon off;
+
+error_log  /dev/stdout;
+
+events {
+    worker_connections  1024;
+}
+
+http {
+    default_type  application/octet-stream;
+    log_format json escape=json
+      '{'
+        '"timestamp":"$time_iso8601",'
+        '"msec":"$msec",'
+        '"request_id":"$request_id",'
+        '"remote_addr":"$remote_addr",'
+        '"remote_user":"$remote_user",'
+        '"request":"$request",'
+        '"status":$status,'
+        '"body_bytes_sent":$body_bytes_sent,'
+        '"referer":"$http_referer",'
+        '"user_agent":"$http_user_agent",'
+        '"http_x_forwarded_for":"$http_x_forwarded_for"'
+      '}';
+
+    keepalive_timeout  65;
+
+    server {
+        listen       8000;
+        server_name  localhost;
+
+        access_log /dev/stdout json;
+
+        location / {
+            try_files $uri @app;
+        }
+
+        location @app {
+            uwsgi_pass uwsgi://localhost:8080;
+            uwsgi_param  QUERY_STRING       $query_string;
+            uwsgi_param  REQUEST_METHOD     $request_method;
+            uwsgi_param  CONTENT_TYPE       $content_type;
+            uwsgi_param  CONTENT_LENGTH     $content_length;
+
+            uwsgi_param  REQUEST_URI        $request_uri;
+            uwsgi_param  PATH_INFO          $document_uri;
+            uwsgi_param  DOCUMENT_ROOT      $document_root;
+            uwsgi_param  SERVER_PROTOCOL    $server_protocol;
+            uwsgi_param  REQUEST_SCHEME     $scheme;
+            uwsgi_param  HTTPS              $https if_not_empty;
+
+            uwsgi_param  REMOTE_ADDR        $remote_addr;
+            uwsgi_param  REMOTE_PORT        $remote_port;
+            uwsgi_param  SERVER_PORT        $server_port;
+            uwsgi_param  SERVER_NAME        $server_name;
+            uwsgi_param  HTTP_X_REQUEST_ID  $request_id;
+        }
+    }
+}

sample-server/uwsgi.ini

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+[uwsgi]
+; general uWSGI config for sample
+callable = app
+module = app
+plugin = python3
+plugin = stdio
+socket = localhost:8080
+
+; logger config
+
+; application logs: log without modifying
+logger = secondlogger stdio
+log-route = secondlogger atst
+log-encoder = format:secondlogger ${msg}
+
+; default uWSGI messages (start, stop, etc.)
+logger = default stdio
+log-route = default ^((?!atst).)*$
+log-encoder = json:default {"timestamp":"${strftime:%%FT%%T}","source":"uwsgi","severity":"DEBUG","message":"${msg}"}
+log-encoder = nl
+
+; uWSGI request logs
+logger-req = stdio
+log-format = request_id=%(var.HTTP_X_REQUEST_ID), pid=%(pid), remote_add=%(addr), request=%(method) %(uri), status=%(status), body_bytes_sent=%(rsize), referer=%(referer), user_agent=%(uagent), http_x_forwarded_for=%(var.HTTP_X_FORWARDED_FOR)
+log-req-encoder = json {"timestamp":"${strftime:%%FT%%T}","source":"req","severity":"INFO","message":"${msg}"}
+log-req-encoder = nl