Add autoscaling using HorizontalPodAutoscaler (close #14)

Author: collimarco

lib/cuber/cuberfile_validator.rb

@@ -81,7 +81,7 @@ def validate_procs
       @options[:procs].each do |procname, proc|
         @errors << "proc \"#{procname}\" name can only include lowercase letters" if procname !~ /\A[a-z]+\z/
         @errors << "proc \"#{procname}\" command must be present" if proc[:cmd].to_s.strip.empty?
-        @errors << "proc \"#{procname}\" scale must be a positive number" unless proc[:scale].is_a?(Integer) && proc[:scale] > 0
+        @errors << "proc \"#{procname}\" scale must be a positive number or a range" unless (proc[:scale].is_a?(Integer) && proc[:scale] > 0) || (proc[:scale].is_a?(Range) && proc[:scale].minmax.all? { |m| m.is_a?(Integer) && m > 0 })
         @errors << "proc \"#{procname}\" cpu must be a positive number" unless proc[:cpu].nil? || proc[:cpu].is_a?(Numeric) && proc[:cpu] > 0
         @errors << "proc \"#{procname}\" ram must be a positive number" unless proc[:ram].nil? || proc[:ram].is_a?(Numeric) && proc[:ram] > 0  
         @errors << "proc \"#{procname}\" term must be a positive number" unless proc[:term].is_a?(Integer) && proc[:term] > 0

lib/cuber/templates/deployment.yml.erb

@@ -131,7 +131,7 @@ metadata:
     app.kubernetes.io/managed-by: cuber
 spec:
   revisionHistoryLimit: 0
-  replicas: <%= proc[:scale] %>
+  replicas: <%= proc[:scale].is_a?(Range) ? proc[:scale].min : proc[:scale] %>
   selector:
     matchLabels:
       app: <%= procname %>-proc
@@ -225,6 +225,34 @@ spec:
       terminationGracePeriodSeconds: <%= proc[:term] %>
 <%- end -%>
 
+<%- @options[:procs].select { |procname, proc| proc[:scale].is_a?(Range) }.each do |procname, proc| -%>
+---
+apiVersion: autoscaling/v2
+kind: HorizontalPodAutoscaler
+metadata:
+  name: scale-<%= procname %>
+  namespace: <%= @options[:app] %>
+  labels:
+    app.kubernetes.io/name: <%= @options[:app].to_s.to_json %>
+    app.kubernetes.io/instance: <%= @options[:instance].to_s.to_json %>
+    app.kubernetes.io/version: <%= @options[:release].to_s.to_json %>
+    app.kubernetes.io/managed-by: cuber
+spec:
+  scaleTargetRef:
+    apiVersion: apps/v1
+    kind: Deployment
+    name: <%= procname %>
+  minReplicas: <%= proc[:scale].min %>
+  maxReplicas: <%= proc[:scale].max %>
+  metrics:
+  - type: Resource
+    resource:
+      name: cpu
+      target:
+        type: Utilization
+        averageUtilization: 60
+<%- end -%>
+
 <%- @options[:cron].each do |jobname, cron| -%>
 ---
 apiVersion: batch/v1

lib/cuber/version.rb

@@ -1,3 +1,3 @@
 module Cuber
-  VERSION = '1.10.0'.freeze
+  VERSION = '1.11.0'.freeze
 end