Similar to #504, say your ~/.fog had multiple stanzas:
```yaml
:default:
:aws_access_key_id: aaa
test:
:aws_access_key_id: bbb
:prod:
:aws_access_key_id: ccc
```
By default, fog will look for either the credential *symbol* `:default` or for the *string* stored in `FOG_CREDENTIAL` (in `lib/fog/core/credentials.rb` method `self.credential`). When the fog credentials file given above is read in, it’s passed through `self.symbolize_credentials` which makes *symbols* out of all the keys (so `prod`, `test`, and `default` will all be symbols) and saves the list to credentials then looks for `credentials[credential]` which is indexing a string in a hash of symbols.
Any value that `@credential` is set to should be a symbol, because the hash keys will only be symbols.
The behavior without this patch is that the performance of the vm_clone
operation in unacceptably slow for VMware vCenter deployments with
multiple hundreds of virtual machines.
Performance is unacceptable because the vm_clone operation makes
multiple API calls to list _all_ of the VM's in the inventory. This
patch eliminates the need to list all VM's by adding path and folder
filters to limit our API calls to subtrees of the VMware inventory.
= API Changes =
* New datacenters request that caches the Datacenter objects for the
life of the process.
* New clone() method on the server model that returns a server model of
the new VM even if it is not yet done cloning.
* Ability to limit collections to inventory paths by passing the
* 'folder' filter to the servers collection. For example:
`conn = Fog::Compute[:vsphere];
conn.servers('path' => '/Datacenters/DC1/vm/Templates')`
this filter will greatly reduce the number of SOAP API calls by
limiting the server models in the collection to only those in the
Templates inventory folder. Note, this is not recursive yet.
= Tests =
Tests have been updated. The vm_clone request no longer takes an
instance_uuid because we cannot actually use this to search the
inventory efficiently. Instead, the vm_clone request now requires a
path attribute to allow Fog to search only a subset of the inventory.
