I think this needs to use local storage? I don't think we can use cookies on Workbench2 which is hosted by a static server (no cookies) and communicates with the API server (which doesn't use cookies).

1. load the remote workbench2 in an invisible iframe, and have the remote wb2's JS code read the "home cluster ID" from the #hash or ?search part of document.location and save it in a cookie/localStorage
2. do an AJAX request to an endpoint on the remote API/controller, which reads the "home cluster ID" from a request header/parameter and sets a cookie in the http response headers, which can later be retrieved by the remote workbench2 using an API endpoint which copies the cookie from request header to response body

In both cases the remote site must first verify that the "set cookie" request really originated from the home cluster, and that the home cluster is among its (the remote site's) configured remote_hosts. Otherwise, any site on the internet visited by a user would be able to change that user's default login selection.

The second (API) approach also requires the "retrieve cookie" API to recognize and trust its own workbench2 origin. The "retrieve cookie" API is unauthenticated -- after all, the whole point is to get this hint before login.

Setting cookies (notes) (copied from https://dev.arvados.org/issues/15061#note-26)

https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS?redirectlocale=en-US&redirectslug=HTTP_access_control#Requests_with_credentials

1. API server publishes CORS header "Access-Control-Allow-Credentials: true" (this enables cross-domain cookies)
2. API server adds a "browserhome" endpoint
3. To set browser home, make ajax call to https://api/browserhome?set=xyzab, withCredentials = true, this responds with "Set-Cookie: browserhome=xyzab" (should this be GET or POST?)
4. To get browser home, make ajax call to https://api/browserhome, withCredentials = true, this will read the Cookie and send it back

(I don't think we can use document.cookie because the wb2 document is served on a different domain from the API server.)

iframe / local storage¶

Using an invisible iframe:

https://medium.com/@crookse/cross-domain-communication-parent-window-and-child-iframe-aaf90fcb3e26

We would want it to load javascript from the same domain as wb2, but not load the full page.

However this has the same security issue as described for cookies, anybody on the internet could use it to set the preferred cluster in localStorage.

ajax / cookies¶

Using an API server endpoint, we could make an authorized call with the salted token. The target cluster would verify the user's identity and respond with a cookie based on the home cluster of the API token (possibly encrypted with api server's rails session secret?)

When the user wants to log in, the wb2 would load the same endpoint, the browser would implicitly provide the cookie, the API server would read the cookie and respond with the preferred home cluster.

More detailed example of the first option from note-9:

1. for each entry in remoteHosts in the current cluster's discovery doc:
   1. retrieve the remote host's discovery doc to find its workbench2 url¹
   2. create a salted token for the remote cluster
   3. make an iframe width="1" height="1" src="https://workbench2.remote.example/#setLoginHint=v2/a-b-c/defg" (where v2/a-b-c/defg is the salted token)
2. window.localStorage.setItem("loginHint", currentUserResponse.uuid)

1. check whether document.location.hash matches ^#setLoginHint=.* -- if not, just continue normal operation
2. use the provided token to get /arvados/v1/users/current from the local cluster, which will recognize it as a salted token and call the home cluster to verify it -- if this fails, log an error to the console for debugging, and stop (the page is in an invisible iframe anyway so showing an error on the page isn't useful)
3. window.localStorage.setItem("loginHint", currentUserResponse.uuid)

1. check window.localStorage.getItem("loginHint"); if not empty, use the first 5 chars of the UUID as the default selection for the login chooser

¹ looks like we need to add this to the discovery doc; currently we only have workbenchUrl → Workbench1.ExternalURL

15064-wb2-fed-login @ commit:f35559bdd3569d836d084524ff64ed050e3c926e

Uses invisible iframe to load federated workbench2 instances using the /fedtoken route which sets the token but does not run the rest of the application.

The /fedtoken route stores credentials in local storage for that site so when user visits other workbench they won't have to log in at all.

The preferred cluster (last logged in cluster) is also set as the "home cluster" in local storage. This affects the default selection on the login screen.

Also updated search to indicate which clusters are being searched, and direct the user to do the search from the home cluster in order for multi-site search to work.

I haven't written any tests. I should probably spend some time learning how to do that.

After clicking "Log in to x33ma with user from x1vn7" on cluster2 after logging into WB2 on cluster1, I get redirected to https://undefined/login?remote=x33ma&return_to=https://172.17.0.3:3001/token, which has an undefined home cluster.

My setup:

cluster1: x1vn7, https://172.17.0.2:3001
cluster2: x3mma, https://172.17.0.3:3001

Local storage while logged into cluster1:

homeCluster:"x1vn7"
apiToken:"v2/x1vn7-gj3su-y1m025skorrigrg/5udgomh9djj72wu2bt8aehawmsujskoeeg4zc0ybarfz906z9"

Local storage at the WB2 login page on cluster2:

homeCluster:"x1vn7"
apiToken:"v2/x1vn7-gj3su-y1m025skorrigrg/d376d54a7c603c964bd881dc4e2c22f0dd5f3861"

Some additional comments:

- In initAuth, there is some console logging that seems like debug code.
- In initAuth, can logout()(dispatch, getState, services); be dispatch(logout()) instead?

Eric Biagiotti wrote:

After clicking "Log in to x33ma with user from x1vn7" on cluster2 after logging into WB2 on cluster1, I get redirected to https://undefined/login?remote=x33ma&return_to=https://172.17.0.3:3001/token, which has an undefined home cluster.

My setup:

cluster1: x1vn7, https://172.17.0.2:3001
cluster2: x3mma, https://172.17.0.3:3001

You have both 'x33ma' and 'x3mma' which looks like a typo somewhere? But maybe it should be able to handle typos better.

Peter Amstutz wrote:

Eric Biagiotti wrote:

After clicking "Log in to x33ma with user from x1vn7" on cluster2 after logging into WB2 on cluster1, I get redirected to https://undefined/login?remote=x33ma&return_to=https://172.17.0.3:3001/token, which has an undefined home cluster.

My setup:

cluster1: x1vn7, https://172.17.0.2:3001
cluster2: x3mma, https://172.17.0.3:3001

You have both 'x33ma' and 'x3mma' which looks like a typo somewhere? But maybe it should be able to handle typos better.

Whoops, that was a typo in my note. My cluster configs are using x33ma.

Looking at the redux state for auth when on the WB2 cluster2 login, I see:

• localCluster: "x33ma"
• homeCluster: "x1vn7"
• remoteHosts:
  • x33ma: "172.17.0.3:8000"

So remoteHosts[homeCluster] returns undefined in auth-services.ts - login.

After getting the federation set up correctly, this works well and LGTM. Thanks!