Adding HTTPS support (mainly for subscription service) about ngas

[aragilar]

So I thought wrapping the server with apache (at AAO North Ryde) would be enough to get https, but the subscription service (on the client side at the AAT) only supports http (so we can't talk to the https server), which is where we need to add the https (so we're not touching the server logic, apart from adding https to the subscription internals). From what internals I've read, as long as we handle the switching between http and https inside ngramsHttpUtils module, then we should have the subscription service (from the client side) have full https support (plus the ngamsPClient will probably get it as a bonus, though I'll leave any explicit support to a later PR if needed).

[rtobar]

Hi @aragilar, similarly to #9, could you clarify the final intent of the changes? The description here and in #9 give me the impression that you either want to add full HTTPS support to NGAS as a whole (not a minor task), or that you'll be pushing files through HTTPS to a separate service. Or are you planning to put a proxy between the two instances to receive via HTTPS and internally proxy via HTTP? I remember you had questions about proxying, so maybe that's what you are planning to do?

Regardless of that, I don't see in principle any problems with adding this.

[rtobar]

Ohhh, by the way, I should actually merge next into master, it doesn't really make sense to maintain two "bleeding edge" branches at all. After that you should be OK branching off the master branch for both PRs.

[rtobar]

Good, that sounds great :)

[aragilar]

I've nearly got something working, I'm still kinda confused what's the purpose of the ngas_hosts table, is that shared between the nodes? It looks like it's used in the proxying logic, but the host_id and domain look to be really short? If the main purpose is proxying, would it be possible to add a column (or another table) with the url the service is running at (including protocol, so we can switch between http and https)?

[awicenec]

James, the standard deployment of NGAS is running many (up to several hundred) instances against the same DB. The sqlite deployment is only used for testing. The host_id plus port and domain had been sufficient up to now to support that. But we do have a few other means to distinguish between instances in the table, including ip_address and mac_address. For your current ‘issue’ that does not help and I would tend to add a protocol column rather than a URL.

…

On 12 Sep 2019, at 15:02, James Tocknell ***@***.***> wrote: I've nearly got something working, I'm still kinda confused what's the purpose of the ngas_hosts table, is that shared between the nodes? It looks like it's used in the proxying logic, but the host_id and domain look to be really short? If the main purpose is proxying, would it be possible to add a column (or another table) with the url the service is running at (including protocol, so we can switch between http and https)? — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub, or mute the thread.

[rtobar]

@aragilar thanks for the update, I'm glad things are going well on your end.

If I understand correctly, you are trying to deploy a subscription like this: NGAS A ----https---> your-proxy ----http---> NGAS B. In this scenario A and B are two separate clusters, have their own database (hence they can't "see" each other that way), and thus there is nothing to be gained by adding, say, an https url in B's ngas_hosts table.

As you found out, and @awicenec points out, the ngas_hosts table makes sense when you think on a deployment of several servers against a single database (hence, a single cluster). In that scenario they all get to know who is present in this shared deployment, which files are were, how to proxy, etc. So yes, it's used for the proxying, but also for other things in multi-server deployments. I agree with Andreas that, if anything, we would add a protocol column, but since the NGAS server currently supports http only there is no need for even that.

Does that clarify a bit the situation?