delayed_jobs_ready metric added to DelayedJob plugin

delayed_jobs_ready instance variable added to metrics

Author: benngarcia

README.md

@@ -540,6 +540,7 @@ end
 | Counter | `delayed_jobs_total`                      | Total number of delayed jobs executed                              | `job_name` |
 | Gauge   | `delayed_jobs_enqueued`                   | Number of enqueued delayed jobs                                    | -          |
 | Gauge   | `delayed_jobs_pending`                    | Number of pending delayed jobs                                     | -          |
+| Gauge   | `delayed_jobs_ready`                      | Number of ready delayed jobs                                       | -          |
 | Counter | `delayed_failed_jobs_total`               | Total number failed delayed jobs executed                          | `job_name` |
 | Counter | `delayed_jobs_max_attempts_reached_total` | Total number of delayed jobs that reached max attempts             | -          |
 | Summary | `delayed_job_duration_seconds_summary`    | Summary of the time it takes jobs to execute                       | `status`   |

lib/prometheus_exporter/instrumentation/delayed_job.rb

@@ -4,6 +4,8 @@ module PrometheusExporter::Instrumentation
   class DelayedJob
     JOB_CLASS_REGEXP = /job_class: ((\w+:{0,2})+)/.freeze
 
+    RuntimeMetric = Struct.new(:max_attempts, :enqueued_count, :pending_count, :ready_count)
+
     class << self
       def register_plugin(client: nil, include_module_name: false)
         instrumenter = self.new(client: client)
@@ -15,13 +17,15 @@ def register_plugin(client: nil, include_module_name: false)
               lifecycle.around(:invoke_job) do |job, *args, &block|
                 max_attempts = Delayed::Worker.max_attempts
                 enqueued_count = Delayed::Job.where(queue: job.queue).count
-                pending_count =
-                  Delayed::Job.where(attempts: 0, locked_at: nil, queue: job.queue).count
+                pending_count = Delayed::Job.where(attempts: 0, locked_at: nil, queue: job.queue).count
+                ready_count = Delayed::Job.where(queue: job.queue, run_at: ..Time.current, locked_at: nil, failed_at: nil).count
+
                 instrumenter.call(
                   job,
                   max_attempts,
                   enqueued_count,
                   pending_count,
+                  ready_count,
                   include_module_name,
                   *args,
                   &block
@@ -38,7 +42,7 @@ def initialize(client: nil)
       @client = client || PrometheusExporter::Client.default
     end
 
-    def call(job, max_attempts, enqueued_count, pending_count, include_module_name, *args, &block)
+    def call(job, max_attempts, enqueued_count, pending_count, ready_count, include_module_name, *args, &block)
       success = false
       start = ::Process.clock_gettime(::Process::CLOCK_MONOTONIC)
       latency = Time.current - job.run_at
@@ -60,6 +64,7 @@ def call(job, max_attempts, enqueued_count, pending_count, include_module_name,
         max_attempts: max_attempts,
         enqueued: enqueued_count,
         pending: pending_count,
+        ready: ready_count
       )
     end
   end

lib/prometheus_exporter/server/delayed_job_collector.rb

@@ -13,6 +13,7 @@ def initialize
       @delayed_job_attempts_summary = nil
       @delayed_jobs_enqueued = nil
       @delayed_jobs_pending = nil
+      @delayed_jobs_ready = nil
     end
 
     def type
@@ -48,6 +49,7 @@ def collect(obj)
       @delayed_job_attempts_summary.observe(obj["attempts"], counter_labels) if obj["success"]
       @delayed_jobs_enqueued.observe(obj["enqueued"], gauge_labels)
       @delayed_jobs_pending.observe(obj["pending"], gauge_labels)
+      @delayed_jobs_ready.observe(obj["ready"], gauge_labels)
     end
 
     def metrics
@@ -62,6 +64,7 @@ def metrics
           @delayed_job_attempts_summary,
           @delayed_jobs_enqueued,
           @delayed_jobs_pending,
+          @delayed_jobs_ready,
         ]
       else
         []
@@ -102,6 +105,11 @@ def ensure_delayed_job_metrics
             "Number of pending delayed jobs.",
           )
 
+        @delayed_jobs_ready =
+        PrometheusExporter::Metric::Gauge.new(
+          "delayed_jobs_ready", "Number of ready delayed jobs."
+        )
+
         @delayed_failed_jobs_total =
           PrometheusExporter::Metric::Counter.new(
             "delayed_failed_jobs_total",