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https://github.com/jonashackt/traefik-cache-nginx-spring-boot
Example project showing how to use Nginx as a simple cache for Traefik - incl. a Spring Boot client and server
https://github.com/jonashackt/traefik-cache-nginx-spring-boot
caching docker-compose-rule docker-network nginx rest-template spring-boot traefik
Last synced: 20 days ago
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Example project showing how to use Nginx as a simple cache for Traefik - incl. a Spring Boot client and server
- Host: GitHub
- URL: https://github.com/jonashackt/traefik-cache-nginx-spring-boot
- Owner: jonashackt
- License: mit
- Created: 2018-03-13T14:33:16.000Z (over 6 years ago)
- Default Branch: master
- Last Pushed: 2024-10-24T16:33:50.000Z (23 days ago)
- Last Synced: 2024-10-25T23:24:08.096Z (21 days ago)
- Topics: caching, docker-compose-rule, docker-network, nginx, rest-template, spring-boot, traefik
- Language: Java
- Size: 1.03 MB
- Stars: 21
- Watchers: 3
- Forks: 9
- Open Issues: 9
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
traefik-cache-nginx-spring-boot
=============================
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As [Traefik](https://traefik.io/) is a really gread & modern loadbalancer, but it sadly [doesn´t feature caching right now](https://github.com/containous/traefik/issues/878). So we need to put something in front of it, that is able to do caching - like old [Nginx](https://nginx.org/en/).
And as I like full examples, let´s bring in a client application (weatherclient), which want´s to call a server backend (weatherbackend). Both are implemented as simple Spring Boot microservices, as the following ASCII shows:
```
-----------------------------------------------------------------------------
| Docker Network scope |
| |
| |
| |
============ | ============== ================ =============== ============ |
= docker- = | = = = = = = = = |
= network- = -----> = weather = --> = Nginx = --> = Traefik = --> = weather = |
= client = | = client = = (caching) = = (loadbalan.)= = backend = |
============ | ============== ================ =============== ============ |
| |
| |
| |
-----------------------------------------------------------------------------
```
It also shows, that we simulate the whole scenario with [Docker](https://www.docker.com/). To have the chance to execute everything within an intergration test, we use [docker-compose-rule](https://github.com/palantir/docker-compose-rule) and the docker-network-client app. Why?
As the weatherclient only has access to the DNS alias `weatherbackend`, if it itself is part of the Docker (Compose) network, we need another way to run an Integration test inside the Docker network scope. Therefore we use the [docker-compose-rule](https://github.com/palantir/docker-compose-rule) and the __docker-network-client__ that just calls __weatherclient__ inside the Docker network.
## HowTo Use
Everything you need to run a full build and __complete__ test (incl. Integrationtest of docker-network-client firing up all microservices that´ll call each other with client certificate support) is this:
```
mvn clean install
```
Only if you want to check everything manually - which you for sure want to do :) - fire up all components with:
```
docker-compose up -d
```
Now you can have a look at some of the components of our architecture:
Traefik: http://localhost:8080/dashboard/#/
weatherclient: http://localhost:8085/swagger-ui.html
Nginx: http://localhost:8088/
#### Alternative variant without Docker-Compose for the Dockerized Spring Boot backends
In a real world DevOps scenario, you may want to run Traefik separate from the Dockerized Spring Boot backends - so that each Backend is able to have it's own CI/CD pipeline for example (e.g. GitLab CI).
Now in this case you don't want a central `docker-compose.yml`, since you want to run and scale all the services independently.
There's a way to run Traefik and the backends separately, as shown in the [docker-compose-traefik-only.yml](docker-compose-traefik-only.yml) [without-compose.sh](without-compose.sh) files:
```yaml
version: '3.8'
services:
traefik:
image: traefik
command:
# - "--logLevel=DEBUG"
- "--api.insecure=true"
# Enabling docker provider
- "--providers.docker=true"
# Do not expose containers unless explicitly told so
- "--providers.docker.exposedbydefault=false"
- "--entrypoints.web.address=:80"
ports:
- "80:80"
- "8080:8080"
networks:
- traefiknet
volumes:
- "/var/run/docker.sock:/var/run/docker.sock:ro"
restart:
always
networks:
traefiknet:
```
```shell script
#!/usr/bin/env bash
echo "[-->] Start Traefik using Compose as usual"
docker-compose -f docker-compose-traefik-only.yml up -d
echo "[-->] Startup weatherbackend without Compose - but connect to Traefik"
docker build ./weatherbackend --tag weatherbackend
docker run \
--rm \
-d \
-p 8095 \
--label="traefik.enable=true" \
--label="traefik.http.routers.whoami.entrypoints=web" \
--label="traefik.http.routers.weatherbackend.rule=Host(\`weatherbackend.server.test\`)" \
--network="traefik-cache-nginx-spring-boot_traefiknet" \
--name weatherbackend \
weatherbackend
echo "[-->] Startup weatherclient without Compose - but connect to Traefik"
docker build ./weatherclient --tag weatherclient
docker run \
--rm \
-d \
-p 8085:8085 \
--network="traefik-cache-nginx-spring-boot_traefiknet" \
--name weatherclient \
weatherclient
```
The downside of this approach is, that one cannot use the scaling option of Docker-Compose now so easily.
## Nginx + Traefik + weatherbackend in logical scope (aka host) with the help of Docker DNS
Additionally, in real world scenarios, Nginx + Traefik + weatherbackend would reside on a separate host with their own DNS configuration. So there´s a second "logical" scope here, which we could have implemented with tools like Vagrant - but this would have been overkill here.
Trying to imitate a machine, where Traefik + weatherbackend + Nginx are running all on one machine with DNS configured, we configure the [Docker DNS alias](https://docs.docker.com/v17.09/engine/userguide/networking/configure-dns/) for weatherbackend to the Traefik container, which routes it then to the weatherbackend. This is done with the help of this Docker Compose configuration ([see the docs](https://docs.docker.com/compose/compose-file/#aliases)):
```
traefik:
...
networks:
default:
aliases:
- weatherbackend.server.test
...
```
Instead of configuring the weatherbackend directly to have the DNS alias `weatherbackend.server.test`, we use the Traefik Docker Compose service here - which has a similar effect to a scoped machine around Nginx, Traefik & weatherbackend. We should see the call now in Traefik GUI:
## Now installing Nginx as cache
To see what´s happening, we need to activate Nginx´ logging to the Docker log system. As we use the alpine image here, we need to [create our own Dockerfile for that](https://stackoverflow.com/a/42369571/4964553):
```
FROM nginx:alpine
# forward request and error logs to docker log collector
RUN ln -sf /dev/stdout /var/log/nginx/access.log \
&& ln -sf /dev/stderr /var/log/nginx/error.log
CMD ["nginx-debug", "-g", "daemon off;"]
```
Additionally, we need to imitate the Scope of Nginx + Traefik + weatherbackend again - now that Nginx is at front of all three:
```
nginx:
build: ./nginx
...
...
networks:
default:
aliases:
- weatherbackend.server.test
...
```
Now, the [WeatherclientController.class](https://github.com/jonashackt/traefik-cache-nginx-spring-boot/blob/master/weatherclient/src/main/java/de/jonashackt/controller/WeatherclientController.java) needs to access Nginx instead of Traefik directly. This is done with the like the [first tutorial steps with Traefik discribe](https://blog.codecentric.de/en/2017/09/traefik-modern-reverse-proxy/) - like the famous curl:
```
curl -H Host:weatherbackend.server.test http://nginx:80 -v
```
We therefore set the `Host` header when using Spring´s RestTemplate:
```
import org.springframework.http.*;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.ResponseStatus;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
import javax.annotation.PostConstruct;
@RestController
public class WeatherclientController {
private RestTemplate restTemplate = new RestTemplate();
/*
* Without the System property, we won´t be able to set the Host header, see
* https://stackoverflow.com/questions/43223261/setting-host-header-for-spring-resttemplate-doesnt-work/43224279
* and https://stackoverflow.com/a/8172736/4964553
*/
@PostConstruct
public void setProperty() {
System.setProperty("sun.net.http.allowRestrictedHeaders", "true");
}
@GetMapping("/forecast/{cityname}")
@ResponseStatus(HttpStatus.OK)
public String forecast(@PathVariable("cityname") String cityname) {
HttpHeaders headers = new HttpHeaders();
headers.set("Host", "weatherbackend.server.test");
ResponseEntity responseEntity = restTemplate.exchange("http://nginx:80/weather/" + cityname,
HttpMethod.GET,
new HttpEntity(null, headers),
String.class);
return responseEntity.getBody();
}
}
```
As you maybe already noticed, setting the Host header in this way [is only possible](https://stackoverflow.com/a/43224279/4964553), if we set `System.setProperty("sun.net.http.allowRestrictedHeaders", "true");`, like we do it in Spring style:
```
/*
* Without the System property, we won´t be able to set the Host header, see
* https://stackoverflow.com/questions/43223261/setting-host-header-for-spring-resttemplate-doesnt-work/43224279
* and https://stackoverflow.com/a/8172736/4964553
*/
@PostConstruct
public void setProperty() {
System.setProperty("sun.net.http.allowRestrictedHeaders", "true");
}
```
Now our setup works perfectly fine. If you fire many requests with the help of `weatherclient`, using Springfox Swagger GUI at http://localhost:8085/swagger-ui.html#!/weatherclient45controller/forecastUsingGET and do a `docker logs NginxContainerIdHere --follow` to see the logs of Nginx and a `docker logs weatherbackendContainerIdHere` to see the logs of the `weatherbackend`, you´ll notice only __one__ call in Traefik and __one__ call of the weatherbackend:
But you´ll notice many calls inside Nginx:
