(maint) Support any vmpooler for ABS via vmpooler_fallback

Before this change, the fallback vmpooler for ABS had to be named
'vmpooler' and it only supported one. With this new code, users can
set a key within an 'abs' service type called vmpooler_fallback that
points to any other service configured in the ~/.vmfloaty.yml config
file. If not set, the appropriate error message is returned, with
an example configuration.
Added the various use cases for the config to the unit tests

lib/vmfloaty/abs.rb

@@ -210,7 +210,7 @@ class ABS
   end
 
   # Retrieve an OS from ABS.
-  def self.retrieve(verbose, os_types, token, url, user, options, _ondemand = nil)
+  def self.retrieve(verbose, os_types, token, url, user, config, _ondemand = nil)
     #
     # Contents of post must be like:
     #
@@ -231,7 +231,7 @@ class ABS
     conn.headers['X-AUTH-TOKEN'] = token if token
 
     saved_job_id = DateTime.now.strftime('%Q')
-    vmpooler_config = Utils.get_vmpooler_service_config
+    vmpooler_config = Utils.get_vmpooler_service_config(config['vmpooler_fallback'])
     req_obj = {
       :resources => os_types,
       :job       => {
@@ -243,15 +243,15 @@ class ABS
       :vm_token => vmpooler_config['token'] # request with this token, on behalf of this user
     }
 
-    if options['priority']
-      req_obj[:priority] = if options['priority'] == 'high'
+    if config['priority']
+      req_obj[:priority] = if config['priority'] == 'high'
                              1
-                           elsif options['priority'] == 'medium'
+                           elsif config['priority'] == 'medium'
                              2
-                           elsif options['priority'] == 'low'
+                           elsif config['priority'] == 'low'
                              3
                            else
-                             options['priority'].to_i
+                             config['priority'].to_i
                            end
     end
 

lib/vmfloaty/service.rb

@@ -141,11 +141,11 @@ class Service
   def maybe_use_vmpooler
     if @service_object.is_a?(ABS.class)
       if !self.silent
-        FloatyLogger.info "The service in use is ABS, but the requested method should run against vmpooler directly, using vmpooler config from ~/.vmfloaty.yml"
+        FloatyLogger.info "The service in use is ABS, but the requested method should run against vmpooler directly, using fallback_vmpooler config from ~/.vmfloaty.yml"
         self.silent = true
       end
 
-      @config = Utils.get_vmpooler_service_config
+      @config = Utils.get_vmpooler_service_config(@config['vmpooler_fallback'])
       @service_object = Pooler
     end
   end

lib/vmfloaty/utils.rb

@@ -251,7 +251,7 @@ class Utils
   end
 
   # This method gets the vmpooler service configured in ~/.vmfloaty
-  def self.get_vmpooler_service_config
+  def self.get_vmpooler_service_config(vmpooler_fallback)
     config = Conf.read_config
     # The top-level url, user, and token values in the config file are treated as defaults
     service_config = {
@@ -262,11 +262,15 @@ class Utils
     }
 
     # at a minimum, the url needs to be configured
-    if config['services'] && config['services']['vmpooler'] && config['services']['vmpooler']['url']
+    if config['services'] && config['services'][vmpooler_fallback] && config['services'][vmpooler_fallback]['url']
       # If the service is configured but some values are missing, use the top-level defaults to fill them in
-      service_config.merge! config['services']['vmpooler']
+      service_config.merge! config['services'][vmpooler_fallback]
     else
-      raise ArgumentError, "Could not find a configured service named 'vmpooler' in ~/.vmfloaty.yml use this format:\nservices:\n  vmpooler:\n    url: 'http://vmpooler.com'\n    user: 'superman'\n    token: 'kryptonite'"
+      if vmpooler_fallback.nil?
+        raise ArgumentError, "The abs service should have a key named 'vmpooler_fallback' in ~/.vmfloaty.yml with a value that points to a vmpooler service name use this format:\nservices:\n  myabs:\n    url: 'http://abs.com'\n    user: 'superman'\n    token: 'kryptonite'\n    vmpooler_fallback: 'myvmpooler'\n  myvmpooler:\n    url: 'http://vmpooler.com'\n    user: 'superman'\n    token: 'kryptonite'"
+      else
+        raise ArgumentError, "Could not find a configured service named '#{vmpooler_fallback}' in ~/.vmfloaty.yml use this format:\nservices:\n  #{vmpooler_fallback}:\n    url: 'http://vmpooler.com'\n    user: 'superman'\n    token: 'kryptonite'"
+      end
     end
 
     service_config