add AWS CloudWatch metrics

Gemfile

@@ -11,6 +11,7 @@ gem "rackup", "~> 2.0"
 gem "sinatra", "~> 4.2"
 
 group :development, :test do
+  gem "aws-sdk-cloudwatch", "~> 1.128"
   gem "database_cleaner", "~> 2.0"
   gem "dotenv", "~> 3.0"
   gem "factory_bot", "~> 6.0"

Gemfile.lock

@@ -26,6 +26,21 @@ GEM
       securerandom (>= 0.3)
       tzinfo (~> 2.0, >= 2.0.5)
     ast (2.4.2)
+    aws-eventstream (1.4.0)
+    aws-partitions (1.1202.0)
+    aws-sdk-cloudwatch (1.128.0)
+      aws-sdk-core (~> 3, >= 3.241.3)
+      aws-sigv4 (~> 1.5)
+    aws-sdk-core (3.241.3)
+      aws-eventstream (~> 1, >= 1.3.0)
+      aws-partitions (~> 1, >= 1.992.0)
+      aws-sigv4 (~> 1.9)
+      base64
+      bigdecimal
+      jmespath (~> 1, >= 1.6.1)
+      logger
+    aws-sigv4 (1.12.1)
+      aws-eventstream (~> 1, >= 1.0.2)
     base64 (0.3.0)
     benchmark (0.4.1)
     bigdecimal (3.2.2)
@@ -54,6 +69,7 @@ GEM
     foreman (0.87.2)
     i18n (1.14.7)
       concurrent-ruby (~> 1.0)
+    jmespath (1.6.2)
     json (2.9.1)
     language_server-protocol (3.17.0.3)
     listen (3.9.0)
@@ -167,6 +183,7 @@ PLATFORMS
   x86_64-linux
 
 DEPENDENCIES
+  aws-sdk-cloudwatch (~> 1.128)
   coveralls_reborn
   database_cleaner (~> 2.0)
   dotenv (~> 3.0)

bin/outboxer_cloudwatch_metrics

@@ -0,0 +1,81 @@
+#!/usr/bin/env ruby
+
+require "bundler/setup"
+
+begin
+  require "aws-sdk-cloudwatch"
+rescue LoadError
+  abort <<~MSG
+    aws-sdk-cloudwatch is not installed.
+
+    Add it to your Gemfile:
+
+      gem "aws-sdk-cloudwatch"
+
+    Then run bundle install.
+  MSG
+end
+
+require "outboxer"
+
+sleep_interval = 60
+tick_interval = 1
+
+environment = ENV["RAILS_ENV"] || "development"
+db_config = Outboxer::Database.config(environment: environment, pool: 1)
+Outboxer::Database.connect(config: db_config)
+
+running = true
+
+["TERM", "INT"].each do |signal|
+  Signal.trap(signal) { running = false }
+end
+
+cloud_watch_client = Aws::CloudWatch::Client.new(
+  credentials: Aws::Credentials.new(
+    ENV.fetch("AWS_ACCESS_KEY_ID"), ENV.fetch("AWS_SECRET_ACCESS_KEY")
+  ),
+  region: ENV.fetch("AWS_REGION"),
+  ssl_verify_peer: false
+)
+
+logger = Outboxer::Logger.new($stdout, level: 1)
+logger.info "Sending Outboxer metrics to CloudWatch..."
+
+while running
+  metrics_by_status = Outboxer::Message.metrics_by_status
+
+  metric_data = metrics_by_status.except(:total).map do |status, metrics|
+    {
+      metric_name: "MessageCount",
+      dimensions: [
+        { name: "Status", value: status.to_s.capitalize },
+        { name: "Environment", value: environment }
+      ],
+      value: metrics[:count],
+      unit: "Count"
+    }
+  end + [
+    {
+      metric_name: "MessageLatency",
+      dimensions: [
+        { name: "Status", value: "Queued" },
+        { name: "Environment", value: environment }
+      ],
+      value: metrics_by_status[:queued][:latency] || 0,
+      unit: "Seconds"
+    }
+  ]
+
+  cloud_watch_client.put_metric_data(namespace: "Outboxer", metric_data: metric_data)
+
+  slept = 0
+
+  while running && slept < sleep_interval
+    sleep tick_interval
+
+    slept += tick_interval
+  end
+end
+
+logger.info "Shutting down"

generators/install_cloudwatch_metrics_generator.rb

@@ -0,0 +1,30 @@
+module Outboxer
+  class InstallCloudwatchMetricsGenerator < Rails::Generators::Base
+    source_root File.expand_path("../", __dir__)
+
+    def copy_bin_file
+      template "bin/outboxer_cloudwatch_metrics", "bin/outboxer_cloudwatch_metrics"
+      run "chmod +x bin/outboxer_cloudwatch_metrics"
+    end
+
+    def print_instructions
+      say <<~MSG
+
+        To complete setup:
+
+          1. Add to Gemfile:
+               gem "aws-sdk-cloudwatch"
+
+          2. Run:
+               bundle install
+
+          3. Start:
+               bin/outboxer_cloudwatch_metrics
+
+      MSG
+    end
+  end
+end
+
+# bundle exec rails g outboxer:install_cloudwatch_metrics
+# bin/outboxer_cloudwatch_metrics

lib/outboxer/web/views/publisher.erb

@@ -117,7 +117,7 @@
                         <td><%= Outboxer::Web.human_readable_size(kilobytes: publisher[:metrics]['rss']) %></td>
                     </tr>
                     <tr>
-                        <th scope="row">Database RTT</th>
+                        <th scope="row">RTT</th>
                         <td><%= Outboxer::Web.pretty_duration_from_seconds(seconds: publisher[:metrics]['rtt']) %></td>
                     </tr>
                 </tbody>