Thanos bucket Web: Provide support to flag web.route-prefix which help to route UI properly

[dmilind]

Thanos, Prometheus and Golang version used:
Using official docker image: thanosio/thanos:v0.15.0

Object Storage Provider: Ceph storage blocks

What happened:
I am using Thanos tools bucket web with --web.external-prefix=/thanos/bucket. Once I hit URL http://localhost:9090/thanos/bucket (k8s service being forwarded to 9090 from 10902 internally), I get 404. When I hit http://localhost:9090 then it shows HTML links only, and when I click on any link it routes me via a prefix path which is okay but again 404. When going through the documentation, I found

      --web.external-prefix=""  Static prefix for all HTML links and redirect
                                URLs in the bucket web UI interface. Actual
                                endpoints are still served on / or the
                                web.route-prefix. This allows thanos bucket web
                                UI to be served behind a reverse proxy that
                                strips a URL sub-path.

Flagweb.route-prefix is mentioned but bucket web does not support it.
I faced a similar issue with the querier and it got resolved when I used web.route-prefix flag.
When I am trying to use this flag for Thanos tools bucket web, it says there is not support for the flag web.route-prefix.

What you expected to happen:
Bucket web UI should be loaded behind the proxy and this can be done by providing support of web.route-prefix flag which is missing as of now.

How to reproduce it (as minimally and precisely as possible):
1

      containers:
        - name: thanos-bucketweb
          image: thanosio/thanos:v0.15.0
          imagePullPolicy: IfNotPresent
          args:
            - tools
            - bucket 
            - web  
            - --log.level=info
            - --http-address=0.0.0.0:10902
            - --web.external-prefix=thanos/bucket
            - --refresh=30m
            - --objstore.config-file=/etc/thanos-store/ceph-object-storage.yaml

2 http://localhost:9090/thanos/bucket 404 page not found
3 http://localhost:9090 HTML UI is displayed and then 404 page not found after clicking a link

Full logs to relevant components:
After providing '--web.route-prefix':

│ Error parsing commandline arguments: [/bin/thanos tools bucket web --log.level=info --http-address=0.0.0.0:10902 --web.route-prefix=thanos/bucket --web.external-prefix=thanos/bucket --refresh=30m --objstore.config-file=/etc/thanos-store/ceph-object-storage.yaml]: unknown long flag '--we │
│ thanos: error: unknown long flag '--web.route-prefix'                                                                                                                                                                                                                                           │
│ stream closed

Anything else we need to know:
I see a similar issue with compact web #2727. If it is fixed then bucket web UI can be fixed easily.

[bwplotka]

Thanks for reporting, it's a bug, help wanted to fix it. (:

[fagossa]

hello, can I take a look into it?

[onprem]

@fagossa Yeah sure. Please go ahead.

[aribalam]

What is the status of the issue? Is it alright to take it?

[fagossa]

hello @aribalam , I'm new to this project so I'm having a hard time testing. If you have the time please go ahead!

Anyways I was looking to this place in bucket.go#L53 where there is a missing / between the prefix and the resource name, which might result in a 404. But again, hard time testing it

instrf := func(name string, next func(w http.ResponseWriter, r *http.Request)) http.HandlerFunc {
    return ins.NewHandler(b.externalPrefix + "/" + name, http.HandlerFunc(next))
}

[dmilind]

@fagossa I think still it will error out for unknown flag web.route-prefix.
While looking in query.go, I found something relative.

if webRoutePrefix != "/" {
			router.Get("/", func(w http.ResponseWriter, r *http.Request) {
				http.Redirect(w, r, webRoutePrefix+"/graph", http.StatusFound)
			})
			router.Get(webRoutePrefix, func(w http.ResponseWriter, r *http.Request) {
				http.Redirect(w, r, webRoutePrefix+"/graph", http.StatusFound)
			})
			router = router.WithPrefix(webRoutePrefix)
}

I think this logic might be helpful.

[aribalam]

@dmilind You are right. The router is not getting prefixed with the web.external-prefix string. Plus, there was another issue that the bucket.html template file did not have a proper link to the new UI. Will open a PR soon.

[dmilind]

Any update on this?

[stale]

Hello 👋 Looks like there was no activity on this issue for the last two months.
Do you mind updating us on the status? Is this still reproducible or needed? If yes, just comment on this PR or push a commit. Thanks! 🤗
If there will be no activity in the next two weeks, this issue will be closed (we can always reopen an issue if we need!). Alternatively, use remind command if you wish to be reminded at some point in future.

[Abhishek357]

I would like to work on this issue.

[stale]

Hello 👋 Looks like there was no activity on this issue for the last two months.
Do you mind updating us on the status? Is this still reproducible or needed? If yes, just comment on this PR or push a commit. Thanks! 🤗
If there will be no activity in the next two weeks, this issue will be closed (we can always reopen an issue if we need!). Alternatively, use remind command if you wish to be reminded at some point in future.

[nextrevision]

@Abhishek357 Thanks for providing a fix for this. Would it be possible to rebase the open MR? I think that's all that is blocking it from merging.

[Abhishek357]

Yeah! sure. Done :)