ec2test: Implement (Un)AssignPrivateIPAddresses

ec2test: Implement (Un)AssignPrivateIPAddresses

Improve the ec2test server by implementing two VPC API calls:
AssignPrivateIPAddresses and UnassignPrivateIPAddresses.

Refactored the local tests for these methods to use the same
code against AWS and ec2test.

https://code.launchpad.net/~dimitern/goamz/120-ec2test-assignip/+merge/221070

(do not edit description out of merge proposal)

[dimitern, 2014-05-27 11:46:41]

Please take a look.

[jameinel, 2014-05-27 12:55:49]

I think LGTM, though I think we'd be happier with 2 collect* style functions.
One that returns a map so you can do O(1) lookups, and one that returns an
ordered slice so that you can iterate over it (without having to turn a map back
into a slice).

https://codereview.appspot.com/100780048/diff/1/ec2/ec2test/server.go
File ec2/ec2test/server.go (right):

https://codereview.appspot.com/100780048/diff/1/ec2/ec2test/server.go#newcode...
ec2/ec2test/server.go:1905: func collectIds(form url.Values, prefix string)
map[string]int {
I take it this change is because you want to collect all the extra IPs but
preserve there order? It seems a shame to make it this complex. I wonder if we'd
be better off having 2 functions, one that just collects into a map, and one
that collects into an ordered slice.

[fwereade, 2014-05-27 12:56:39]

https://codereview.appspot.com/100780048/diff/1/ec2/ec2test/server.go
File ec2/ec2test/server.go (right):

https://codereview.appspot.com/100780048/diff/1/ec2/ec2test/server.go#newcode319
ec2/ec2test/server.go:319: ip[len(ip)-1] += 1
It seems that there's no bounds-checking, and no way of guaranteeing that
different NICs get different IPs. Am I missing something?

[dimitern, 2014-05-27 13:26:19]

Please take a look.

https://codereview.appspot.com/100780048/diff/1/ec2/ec2test/server.go
File ec2/ec2test/server.go (right):

https://codereview.appspot.com/100780048/diff/1/ec2/ec2test/server.go#newcode319
ec2/ec2test/server.go:319: ip[len(ip)-1] += 1
On 2014/05/27 12:56:39, fwereade wrote:
> It seems that there's no bounds-checking, and no way of guaranteeing that
> different NICs get different IPs. Am I missing something?

Correct, uniqueness of IPs across NICs is not enforced, but this is intended for
tests anyway, so it shouldn't be a problem.

https://codereview.appspot.com/100780048/diff/1/ec2/ec2test/server.go#newcode...
ec2/ec2test/server.go:1905: func collectIds(form url.Values, prefix string)
map[string]int {
On 2014/05/27 12:55:48, jameinel wrote:
> I take it this change is because you want to collect all the extra IPs but
> preserve there order? It seems a shame to make it this complex. I wonder if
we'd
> be better off having 2 functions, one that just collects into a map, and one
> that collects into an ordered slice.

I experimented a few solutions, since in only one case we need to preserve the
order, like returning both a map and an ordered slice, but I guess I'm
overcomplicating things here.
Added a new helper to collect entries in order.

[dimitern, 2014-05-27 13:43:24]

*** Submitted:

ec2test: Implement (Un)AssignPrivateIPAddresses

Improve the ec2test server by implementing two VPC API calls:
AssignPrivateIPAddresses and UnassignPrivateIPAddresses.

Refactored the local tests for these methods to use the same
code against AWS and ec2test.

R=jameinel, fwereade
CC=
https://codereview.appspot.com/100780048