Support for using the persistent-auth

[iNecas]

With persisted_auth set to true, we can by-pass the full ovirt authentication,
which can rapidly speed-up the response times
(at least when running against some external authentication).

In my setup, it is 4x faster with this feature turned on. For more details see
http://www.ovirt.org/Features/RESTSessionManagement.

[lzap]

Ivan, we definitely need to cover this with integration tests. See to README how to set things up and you can use this bats suite to install ovirt all-in-one setup.

If you use the bats suite, please give the PR 👍 as nobody is willing to test it for some reason :-)

theforeman/foreman-bats#34

Codewise this WFM

[ohadlevy]

do we need to add some ovirt version tests?

[iNecas]

I think it will just get ignored by older versions and the basic auth will continue to work: it will just not return the jsessionid at the end, so the basic auth will continue to be used for those cases.

[jhernand]

It is better if you avoid using explicitly the JSESSIONID name, as that may change in the server side in the future. Instead of that try to handle correctly all the cookies returned by the server, whatever they are named (not sure if this is possible with the REST client that rbovirt uses).

Also, when implementing this kind of persistent authentication, it is very important to provide a mechanism that can be used to dispose the server side session, otherwise sessions will potentially accumulate in the server and eventually exhaust its resources. Other oVirt API bindings include a disconnect method that takes care of this. This method should send a request to the server, with the session identifier (currently the JSESSIONID cookie), the Prefer: persistent-auth header but no Authorization header:

HEAD /ovirt-engine/api HTTP/1.1
Cookie: JSESSIONID=...
Prefer: persistent-auth

(Note that there is no Authorization header in this request.)

Using the HEAD method for this final request is good because it avoids the transfer of the body of the root resource, which is useless in this case.

[epienbroek]

I just tried this PR and added an initial testcase for it in 29e4501.
During testing I also discovered a copy/paste typo which can be fixed by aa5c1ac
Both changes can be found in my branch @ https://github.com/epienbroek/rbovirt/commits/persistent_test
Feel free to cherry-pick them and add them to this PR

[lzap]

@iNecas ping ^^ can you incorporate and rebase? Interesting patch, nice one.

[lzap]

Keep in mind that if we want this to fix Foreman, we need to backport this into 0.0.3x series as the 0.1 version is not compatible with Fog/Foreman.

[lzap]

It is worth adding a test.

[iNecas]

Tests added (thanks @epienbroek). I've also added another commit to fix the #100

[lzap]

This is great work Ivan, I am gonna to test this now.

[lzap]

Tests passed, except these two, but you fixed bunch of others so this is PASS :-)

Failures:

  1) Admin API VM Life cycle admin basic vm and templates operations behaves like Basic VM Life cycle test_should_start_with_cloudinit
     Failure/Error: @client.vm_start_with_cloudinit(@vm.id, user_data)
     OVIRT::OvirtException:
       Cannot run VM because the VM is in Powering Down status.
     Shared Example Group: "Basic VM Life cycle" called from ./spec/integration/vm_crud_spec.rb:130
     # ./lib/rbovirt.rb:207:in `handle_fault'
     # ./lib/rbovirt.rb:127:in `rescue in http_post'
     # ./lib/rbovirt.rb:124:in `http_post'
     # ./lib/client/vm_api.rb:150:in `vm_start_with_cloudinit'
     # ./spec/integration/vm_crud_spec.rb:47:in `block (2 levels) in <top (required)>'

  2) User API VM Life cycle user basic vm and templates operations behaves like Basic VM Life cycle test_should_start_with_cloudinit
     Failure/Error: @client.vm_start_with_cloudinit(@vm.id, user_data)
     OVIRT::OvirtException:
       Cannot run VM because the VM is in Powering Down status.
     Shared Example Group: "Basic VM Life cycle" called from ./spec/integration/vm_crud_spec.rb:152
     # ./lib/rbovirt.rb:207:in `handle_fault'
     # ./lib/rbovirt.rb:127:in `rescue in http_post'
     # ./lib/rbovirt.rb:124:in `http_post'
     # ./lib/client/vm_api.rb:150:in `vm_start_with_cloudinit'
     # ./spec/integration/vm_crud_spec.rb:47:in `block (2 levels) in <top (required)>'

Merging as well into 0.0.x series.

[lzap]

Merged as cf4e205, thank you!