feat: add provider specific proxy option

[sboschman]

Issue: #982

Depends on pr rancher/norman #453

As this pr depends on norman it is a draft pr, till we can get the required change merged into norman.

Problem

Currently a proxy url can only be set as environment variable, which is used by all providers in the terraform run. If only Rancher requests should be proxied, a provider based proxy setting is required.

Solution

Added extra provider config option proxy_url to set a proxy server to use to connect to the Rancher instance.

Testing

Engineering Testing

Manual Testing

Locally tested to run a tf plan/apply with a Rancher instance behind a Cloudflare Zero Trust tunnel, requiring a localhost proxy to connect and authenticate to Cloudflare.

Automated Testing

Added testcases to check the validation of the proxy_url config. It should only accept parsable http, https or socks5 urls.

QA Testing Considerations

Regressions Considerations

[kkaempf]

closing stale PRs.
If you still intend to work on this, please reopen.

[sboschman]

I am waiting for rancher/norman#453 to be merged, this draft PR is working (we are running with a self compiled provider binary based on this patch as local override).

@kkaempf , do you have any idea who we could ping with regards to that rancher/norman PR to get this moving along?

[ericpromislow]

rancher/norman#453 has been merged, but the go dependencies need to be updated. Could you please do that and re-push?

[sboschman]

@ericpromislow as norman now requires go 1.22 and terraform-provider-rancher2 is on 1.19, perhaps it is better to bump the norman dep in a separate PR?

go: github.com/rancher/[email protected] requires go >= 1.22; switching to go1.22.2

From the drone ci logs:

Step 1/3 : FROM golang:1.19.4-alpine3.16

So, I assume bumping norman also requires some changes to the ci steps.

[ericpromislow]

@sboschman Thanks, I'll have a look

[ericpromislow]

Could you pull this out of draft mode so I can see what happens in CI? This repo doesn't have a make ci like most of the other rancher repo's so I can't easily verify it.

[ericpromislow]

Also I noticed the following problems with this repo with go 1.22 on both macos and ubuntu:

$ make build
…
go: modules disabled by GO111MODULE=off; see 'go help modules'
make: *** [lint] Error 1

AFAIK this variable is no longer needed. After I pull out the two GO111MODULE=X constructs from GNUmakefile and run this:

$ make build
# outputs go mod messages
$ go get -u
$ go mod tidy
$ make build

go vet complains about duplicate json tag type in both norman.Resource and v1.Secret embedded in type SecretV2 -- I don't know how this got passed earlier versions of go vet, and don't know if the t-p-r CI runs this.