Merge pull request #103 from cablett/cablett-everything-structured-log

Catch fatal errors and output as structured

lib/mail_room.rb

@@ -13,3 +13,4 @@ module MailRoom
 require "mail_room/coordinator"
 require "mail_room/cli"
 require 'mail_room/logger/structured'
+require 'mail_room/crash_handler'

lib/mail_room/cli.rb

@@ -2,14 +2,14 @@ module MailRoom
   # The CLI parses ARGV into configuration to start the coordinator with.
   # @author Tony Pitale
   class CLI
-    attr_accessor :configuration, :coordinator
+    attr_accessor :configuration, :coordinator, :options
 
     # Initialize a new CLI instance to handle option parsing from arguments
     #   into configuration to start the coordinator running on all mailboxes
     #
     # @param args [Array] `ARGV` passed from `bin/mail_room`
     def initialize(args)
-      options = {}
+      @options = {}
 
       OptionParser.new do |parser|
         parser.banner = [
@@ -25,6 +25,10 @@ def initialize(args)
           options[:quiet] = true
         end
 
+        parser.on('--log-exit-as') do |format|
+          options[:exit_error_format] = 'json' unless format.nil?
+        end
+
         # parser.on("-l", "--log FILE") do |path|
         #   options[:log_path] = path
         # end
@@ -50,6 +54,9 @@ def start
       end
 
       coordinator.run
+    rescue Exception => e # not just Errors, but includes lower-level Exceptions
+      CrashHandler.new(error: e, format: @options[:exit_error_format]).handle
+      exit
     end
   end
 end

lib/mail_room/crash_handler.rb

@@ -0,0 +1,29 @@
+
+module MailRoom
+  class CrashHandler
+
+    attr_reader :error, :format
+
+    SUPPORTED_FORMATS = %w[json none]
+
+    def initialize(error:, format:)
+      @error = error
+      @format = format
+    end
+
+    def handle
+      if format == 'json'
+        puts json
+        return
+      end
+
+      raise error
+    end
+
+    private
+
+    def json
+      { time: Time.now, severity: :fatal, message: error.message, backtrace: error.backtrace }.to_json
+    end
+  end
+end

spec/lib/cli_spec.rb

@@ -37,5 +37,25 @@
 
       expect(coordinator).to have_received(:run)
     end
+
+    context 'on error' do
+      let(:error_message) { "oh noes!" }
+      let(:coordinator) { OpenStruct.new(run: true, quit: true) }
+
+      before do
+        cli.instance_variable_set(:@options, {exit_error_format: error_format})
+        coordinator.stubs(:run).raises(RuntimeError, error_message)
+      end
+
+      context 'json format provided' do
+        let(:error_format) { 'json' }
+
+        it 'passes onto CrashHandler' do
+          cli.start
+
+          expect(MailRoom::CrashHandler).to have_received(:new).with a_hash_including({format: error_format})
+        end
+      end
+    end
   end
 end

spec/lib/crash_handler_spec.rb

@@ -0,0 +1,41 @@
+require 'spec_helper'
+
+describe MailRoom::CrashHandler do
+
+  let(:error_message) { "oh noes!" }
+  let(:error) { RuntimeError.new(error_message) }
+
+  describe '#handle' do
+
+    subject{ described_class.new(error: error, format: format) }
+
+    context 'when given a json format' do
+      let(:format) { 'json' }
+      let(:fake_json) do
+        { message: error_message }.to_json
+      end
+
+      it 'outputs the result of json to stdout' do
+        subject.stubs(:json).returns(fake_json)
+
+        expect{ subject.handle }.to output(/\"message\":\"#{error_message}\"/).to_stdout
+      end
+    end
+
+    context 'when given a blank format' do
+      let(:format) { "" }
+
+      it 'raises an error as designed' do
+        expect{ subject.handle }.to raise_error(error.class, error_message)
+      end
+    end
+
+    context 'when given a nonexistent format' do
+      let(:format) { "nonsense" }
+
+      it 'raises an error as designed' do
+        expect{ subject.handle }.to raise_error(error.class, error_message)
+      end
+    end
+  end
+end

spec/lib/logger/structured_spec.rb

@@ -21,7 +21,7 @@
     expect { subject.unknown(message) }.to output(json_matching("ANY", message)).to_stdout_from_any_process
   end
 
-  it 'only accepts strings' do
+  it 'only accepts hashes' do
     expect { subject.unknown("just a string!") }.to raise_error(ArgumentError, /must be a Hash/)
   end