Add capability to disable fallback in a phpa config

Author: ashu210890

examples/graphite-config-example.yml

@@ -2,6 +2,7 @@ version: 'v1'
 kind: 'PHPAConfig'
 verbose: 'true'
 dryRun: 'true'
+fallbackEnabled: 'false'
 # cool down time(in seconds) after performing an action
 actionCooldown: '300'
 # interval (in seconds) between consecutive checks of phpa for this deployment

examples/influx-config-example.yaml

@@ -4,6 +4,7 @@ kind: 'PHPAConfig'
 verbose: 'true'
 # interval (in seconds) between consecutive checks of phpa for this deployment
 interval: '300'
+fallbackEnabled: 'false'
 deployment:
   name: 'backend-staging-deployment'
   namespace: 'backend-app'

lib/config.rb

@@ -22,7 +22,7 @@ class Config
                   :deploy_name, :namespace, :adaptor, :server, \
                   :min_replicas, :max_replicas, :fallback_replicas, \
                   :metric_name, :metric_type, :metric_threshold, :metric_margin, \
-                  :interval
+                  :interval, :fallback_enabled
 
     def initialize(file_path)
       config = YAML.load_file(file_path)
@@ -35,6 +35,7 @@ def initialize(file_path)
 
       @verbose = config[:verbose] == 'true' ? true : false
       @dry_run = config[:dryRun] == 'true' ? true : false
+      @fallback_enabled = config[:fallbackEnabled] == 'false' ? false : true
       action_cooldown = config[:actionCooldown] || DEFAULT_ACTION_COOLDOWN
       @action_cooldown = action_cooldown.to_i
       interval = config[:interval] || DEFAULT_INTERVAL

lib/kubernetes_runner.rb

@@ -50,6 +50,11 @@ def perform_action(config)
         result[:failed] = true
         return result
       when :unknown
+        unless config.fallback_enabled
+          log_txt "Action: #{action}, Not triggering fallback as "\
+            "fallback is not enabled"
+          scale_to = current
+        end
         # we went to reach to fallback_replicas slowly
         scale_to = fallback_scale_to(current, config.fallback_replicas)
         log_txt "Action: #{action}, fallback to #{scale_to} replicas " \