Add HTTP headers to healthcheck.

[zetaab]

What does this PR do?

Tries to fix issue #3043

Motivation

We need this feature, describe in issue

More

• Added/updated tests
• Added/updated documentation

Additional Notes

Fixes #3043

[zetaab]

This is still WIP

I am adding healthchecks

        "healthcheck": {
            "path": "/",
            "interval": "5s",
            "headers": {
            	"Host": "foobar.com",
            	"header1": "test",
            	"headeR2": "test2"
            }
        },

I can see in logs DEBU[2018-03-19T14:32:53+02:00] Setting up backend health check [Headers: map[Host:foobar.com header1:test headeR2:test2] Path: / Port: 0 Interval: 5s]

However, still I am not able to see Host header in another server.

ERROR:root:Host: 192.168.1.43:8000
User-Agent: Go-http-client/1.1
Header1: test
Header2: test2

I am thinking might this cause this issue still golang/go#7682

[zetaab]

package main

import (
	"fmt"
	"net/http"
	"os"
)

func main() {
	client := &http.Client{}
	req, err := http.NewRequest("GET", "http://localhost:8000", nil)
	if err != nil {
		os.Exit(1)
	}
	req.Header.Add("User-Agent", "myClient")
	req.Header.Add("Host", "leet.com")
	resp, err := client.Do(req)
	defer resp.Body.Close()
	fmt.Println(resp)
}

Does not change host header to leet.com. Cool :). So is this golang bug?

[zetaab]

Got it working, its little bit tricky in Host header. Is these tests and docs enough or do we need more?

I have no idea how to fix these tests:

WARNING: Ignoring http://dl-cdn.alpinelinux.org/alpine/v3.7/community/x86_64/APKINDEX.tar.gz: BAD signature

[juliens]

Thanks for your contribution!

I understand your use case with the hostname, but I'm not sure about changing headers.

Do you think you can just add "hostname option" and remove other headers option?

[zetaab]

@juliens IMO headers are useful for instance if the healthcheck needs authentication. So I do not see why we could not add those in same PR

[juliens]

@zetaab After discussion with the team, we agree to add both hostname and headers on healthcheck.

But we think we need to separate hostname from the headers.
If I take your proposal, it becomes like this:

        "healthcheck": {
            "path": "/",
            "interval": "5s",
            "hostname": "foobar.com",
            "headers": {
            	"header1": "test",
            	"headeR2": "test2"
            }
        },

Moreover, we need the functionnality to be added on every providers.

If you need help, you can share with us on our Slack workspace

[ldez]

@zetaab Could rebase your PR on the master branch.

Also, you have to take this feature available by the labels and the KV:

• edit templates: https://github.com/containous/traefik/tree/master/templates
• run go generate
• edit those sections:
  • https://github.com/containous/traefik/blob/03ce6a1cc4947f138ac3f7893322befd67556dc3/provider/label/partial.go#L231-L245
  • https://github.com/containous/traefik/blob/03ce6a1cc4947f138ac3f7893322befd67556dc3/provider/kv/kv_config.go#L296-L311
• Add tests for all providers (except Kubernetes)

[zetaab]

could someone review these test, I cannot now find the problem(s). To get tests working

edit: now tests are working locally, but ECS provider tests are failing to some another reasons

[ldez]

@zetaab Could you also update the doc for each provider, thanks.

[ldez]

Thank you for your patience and your responsiveness. We really enjoyed that.

LGTM 🎉

[mmatur]

Nice work 👏

[juliens]

LGTM