Nginx Reverse Proxy fallback URL Example

There is a simple example with fallback URL in the nginx as a reverse proxy.

Start Instructions

For using this example you should have installed docker and docker-compose.

For starting this project you should run the command in a console, you should be located in the project directory:

$ docker-compose up

As a result you'll have the started project on the port 8080. For checking rules you should request the url with a http code, for exaple:

$ curl http://127.0.0.1:8080/404
{"Parsed Code":"200","Source URL":"/200","Status Text":"OK"}
$ curl http://127.0.0.1:8080/400
{"Parsed Code":"400","Source URL":"/400","Status Text":"Bad Request"}

Check result of your previous requests in the console where you started docker-compose:

codes    | 2018/02/25 12:34:20 Listening...
codes    | {"Parsed Code":"404","Source URL":"/404","Status Text":"Not Found"}
codes    | {"Parsed Code":"200","Source URL":"/200","Status Text":"OK"}
nginx    | 172.18.0.1 - - [25/Feb/2018:12:34:22 +0000] "GET /404 HTTP/1.1" 200 60 "-" "curl/7.54.0" "-"
codes    | {"Parsed Code":"400","Source URL":"/400","Status Text":"Bad Request"}
nginx    | 172.18.0.1 - - [25/Feb/2018:12:34:24 +0000] "GET /400 HTTP/1.1" 400 69 "-" "curl/7.54.0" "-"

Following the logs from the docker-compose console we can see that:

• The first command curl http://127.0.0.1:8080/404 with the request to the nginx triggered two requests from the nginx to the application of the codes. So we can see the triggered fallback to the 404 code response.
• The second command curl http://127.0.0.1:8080/400 with the request to the nginx triggered only one request from the nginx to the application of the codes.

Change codes which triggering fallback requests

If you want to check some other codes with fallback requests you should open ./conf/www.conf in the project directory and change list of codes in the error page line. For example was set three codes (403, 404, 503) by default in the error_page 403 404 503 = @outage; line, so you could add code 400 error_page 400 403 404 503 = @outage; in this line. After finished changes, you have to save file and restart docker-compose up.

Restrictions

• Application codes supporting only valid codes in other cases you'll get 500 response code with the error message.