Add unit test for check-marathon-task.rb

bin/check-marathon-task.rb

@@ -67,34 +67,15 @@ def run
           h.request(req)
         end
 
-        tasks = JSON.parse(r.body)['tasks']
+        ok_count, unhealthy = check_tasks r.body
 
-        tasks.select! do |t|
-          t['appId'] == "/#{config[:task]}"
-        end
-
-        unhealthy = []
-
-        # Collect last error message for all health checks that are not alive
-        tasks.each do |task|
-          checks = task['healthCheckResults'] || []
-          checks.each do |check|
-            if check['alive']
-              next
-            end
-            message = check['lastFailureCause'] ||
-                      'Health check not alive'
-            unhealthy << message
-          end
-        end
-
-        message = "#{tasks.length}/#{config[:instances]} #{config[:task]} tasks running"
+        message = "#{ok_count}/#{config[:instances]} #{config[:task]} tasks running"
 
         if unhealthy.any?
           message << ":\n" << unhealthy.join("\n")
         end
 
-        if unhealthy.any? || tasks.length < config[:instances]
+        if unhealthy.any? || ok_count < config[:instances]
           critical message
         end
 
@@ -108,4 +89,41 @@ def run
 
     unknown "marathon task state could not be retrieved:\n" << failures.join("\n")
   end
+
+  # Parses JSON data as returned from Marathon's tasks API
+  # @param data [String] Server response
+  # @return [Numeric, [String]] Number of running tasks and a list of error
+  #                             messages from unhealthy tasks
+  def check_tasks(data)
+    begin
+      tasks = JSON.parse(data)['tasks']
+    rescue JSON::ParserError
+      raise "Could not parse JSON response: #{data}"
+    end
+
+    if tasks.nil?
+      raise "No tasks in server response: #{data}"
+    end
+
+    tasks.select! do |t|
+      t['appId'] == "/#{config[:task]}"
+    end
+
+    unhealthy = []
+
+    # Collect last error message for all health checks that are not alive
+    tasks.each do |task|
+      checks = task['healthCheckResults'] || []
+      checks.each do |check|
+        if check['alive']
+          next
+        end
+        message = check['lastFailureCause'] ||
+                  'Health check not alive'
+        unhealthy << message
+      end
+    end
+
+    [tasks.length, unhealthy]
+  end
 end

test/check_marathon_task_spec.rb

@@ -0,0 +1,55 @@
+require_relative './spec_helper.rb'
+require_relative '../bin/check-marathon-task.rb'
+require_relative './fixtures.rb'
+
+# rubocop:disable Style/ClassVars
+class MarathonTaskCheck
+  at_exit do
+    @@autorun = false
+  end
+
+  def critical(*); end
+
+  def warning(*); end
+
+  def ok(*); end
+
+  def unknown(*); end
+end
+
+def check_results(parameters)
+  check = MarathonTaskCheck.new parameters.split(' ')
+  check.check_tasks marathon_response
+end
+
+describe 'MarathonTaskCheck' do
+  before do
+    @default_parameters = '--server localhost --task foo/bar --instances 1'
+    @check = MarathonTaskCheck.new @default_parameters.split(' ')
+  end
+
+  describe '#run' do
+    it 'tests that a single running task is ok' do
+      tasks_ok, unhealthy = check_results @default_parameters
+      expect(tasks_ok).to be 1
+      expect(unhealthy).to be == []
+    end
+
+    it 'counts tasks correctly' do
+      tasks_running, unhealthy = check_results '--server s --task non/existing --instances 1'
+      expect(tasks_running).to be 0
+      expect(unhealthy).to be == []
+    end
+
+    it 'does not count unhealthy tasks' do
+      tasks_running, unhealthy = check_results '--server s --task broken/app --instances 1'
+      expect(tasks_running).to be 2
+      expect(unhealthy.count).to eq 2
+    end
+
+    it 'tests that an empty server response raises an error' do
+      expect { @check.check_tasks '{}' }.to raise_error(/No tasks/)
+      expect { @check.check_tasks '' }.to raise_error(/Could not parse JSON/)
+    end
+  end
+end

test/fixtures.rb

@@ -0,0 +1,116 @@
+def marathon_response
+  <<-EOF
+{
+  "tasks": [
+    {
+      "healthCheckResults": [
+        {
+          "taskId": "foo_bar.0",
+          "lastFailureCause": null,
+          "lastSuccess": "2016-07-14T15:27:48.286Z",
+          "lastFailure": null,
+          "firstSuccess": "2016-07-14T14:10:57.583Z",
+          "consecutiveFailures": 0,
+          "alive": true
+        }
+      ],
+      "servicePorts": [
+        1234
+      ],
+      "appId": "/foo/bar",
+      "ipAddresses": [
+        {
+          "protocol": "IPv4",
+          "ipAddress": "123.123.123.123"
+        }
+      ],
+      "id": "foo_bar.0",
+      "slaveId": "0-S0",
+      "host": "host.example.com",
+      "state": "TASK_RUNNING",
+      "startedAt": "2016-07-14T14:09:43.350Z",
+      "stagedAt": "2016-07-14T14:09:41.953Z",
+      "ports": [
+        123450
+      ],
+      "version": "2016-07-14T14:09:41.270Z"
+    },
+    {
+      "healthCheckResults": [
+        {
+          "taskId": "broken_app.0",
+          "lastFailureCause": null,
+          "lastSuccess": null,
+          "lastFailure": null,
+          "firstSuccess": null,
+          "consecutiveFailures": 0,
+          "alive": false
+        },
+        {
+          "taskId": "broken_app.1",
+          "lastFailureCause": null,
+          "lastSuccess": "2016-07-14T15:27:48.286Z",
+          "lastFailure": null,
+          "firstSuccess": "2016-07-14T14:10:57.583Z",
+          "consecutiveFailures": 0,
+          "alive": true
+        }
+      ],
+      "servicePorts": [
+        1234
+      ],
+      "appId": "/broken/app",
+      "ipAddresses": [
+        {
+          "protocol": "IPv4",
+          "ipAddress": "123.123.123.123"
+        }
+      ],
+      "id": "broken_app.0",
+      "slaveId": "0-S0",
+      "host": "host.example.com",
+      "state": "TASK_RUNNING",
+      "startedAt": "2016-07-14T14:09:43.350Z",
+      "stagedAt": "2016-07-14T14:09:41.953Z",
+      "ports": [
+        123450
+      ],
+      "version": "2016-07-14T14:09:41.270Z"
+    },
+    {
+      "healthCheckResults": [
+        {
+          "taskId": "broken_app.1",
+          "lastFailureCause": "I broke",
+          "lastSuccess": null,
+          "lastFailure": "2016-07-14T14:09:41.270Z",
+          "firstSuccess": null,
+          "consecutiveFailures": 1,
+          "alive": false
+        }
+      ],
+      "servicePorts": [
+        1234
+      ],
+      "appId": "/broken/app",
+      "ipAddresses": [
+        {
+          "protocol": "IPv4",
+          "ipAddress": "123.123.123.123"
+        }
+      ],
+      "id": "broken_app.0",
+      "slaveId": "0-S0",
+      "host": "host.example.com",
+      "state": "TASK_RUNNING",
+      "startedAt": "2016-07-14T14:09:43.350Z",
+      "stagedAt": "2016-07-14T14:09:41.953Z",
+      "ports": [
+        123450
+      ],
+      "version": "2016-07-14T14:09:41.270Z"
+    }
+  ]
+}
+EOF
+end