From b8712ab322226e618bf69f08a60d36fd87c739cb Mon Sep 17 00:00:00 2001
From: Lukas Zapletal <lzap+git@redhat.com>
Date: Mon, 22 Jun 2020 14:58:03 +0200
Subject: [PATCH] Fixes #30029 - telemetry label filter

---
 config/initializers/5_telemetry_metrics.rb    | 72 +++++++++++++++++++
 lib/foreman/telemetry.rb                      | 24 ++++++-
 .../telemetry_sinks/prometheus_sink.rb        |  2 +
 3 files changed, 97 insertions(+), 1 deletion(-)

diff --git a/config/initializers/5_telemetry_metrics.rb b/config/initializers/5_telemetry_metrics.rb
index 2d5f56361fd..024a6710cf6 100644
--- a/config/initializers/5_telemetry_metrics.rb
+++ b/config/initializers/5_telemetry_metrics.rb
@@ -29,3 +29,75 @@
 telemetry.add_counter(:audit_records_created, 'Number of audit records created in the DB', [:type])
 telemetry.add_counter(:audit_records_logged, 'Number of audit records sent into logger', [:type])
 telemetry.add_counter(:config_report_metric_count, 'Number of config report status metrics', [:metric])
+
+# To decrease amount of metrics, labels must be allowed explicitly
+allowed_labels = {
+  controller: [
+    'api/v2/config_reports_controller',
+    'api/v2/hosts_controller',
+    'api/v2/puppet_hosts_controller',
+    'config_reports_controller',
+    'dashboard_controller',
+    'fact_values_controller',
+    'hostgroups_controller',
+    'hosts_controller',
+    'notification_recipients_controller',
+  ],
+  class: [
+    'Architecture',
+    'AuthSource',
+    'Bookmark',
+    'CommonParameter',
+    'ComputeResource',
+    'ConfigReport',
+    'Domain',
+    'DomainParameter',
+    'Environment',
+    'FactName',
+    'FactValue',
+    'Filter',
+    'Filtering',
+    'GroupParameter',
+    'Host::Base',
+    'Host::Managed',
+    'Hostgroup',
+    'HostParameter',
+    'Image',
+    'JobTemplate',
+    'Location',
+    'LocationParameter',
+    'LookupKey',
+    'LookupValue',
+    'Model',
+    'Nic::Base',
+    'Nic::BMC',
+    'Nic::Bond',
+    'Nic::Bridge',
+    'Nic::Interface',
+    'Nic::Managed',
+    'Operatingsystem',
+    'Organization',
+    'OrganizationParameter',
+    'OsParameter',
+    'Parameter',
+    'ProvisioningTemplate',
+    'Ptable',
+    'PuppetclassLookupKey',
+    'Realm',
+    'RemoteExecutionFeature',
+    'Report',
+    'Role',
+    'SmartProxy',
+    'Subnet',
+    'SubnetParameter',
+    'Taxonomy',
+    'Template',
+    'TemplateInput',
+    'TemplateInvocation',
+    'TemplateKind',
+    'User',
+    'Usergroup',
+    'Widget',
+  ],
+}
+telemetry.allowed_tags(allowed_labels)
diff --git a/lib/foreman/telemetry.rb b/lib/foreman/telemetry.rb
index 2d80d50c817..2683903a361 100644
--- a/lib/foreman/telemetry.rb
+++ b/lib/foreman/telemetry.rb
@@ -7,7 +7,7 @@ class Telemetry
     extend Forwardable
     attr_accessor :prefix, :sinks
 
-    DEFAULT_BUCKETS = [1, 5, 20, 50, 100, 250, 500, 2000].freeze
+    DEFAULT_BUCKETS = [100, 500, 3000].freeze
 
     def initialize
       @sinks = []
@@ -96,6 +96,14 @@ def enabled?
       @sinks.count > 1
     end
 
+    def allowed_tags(labels)
+      @allowed_tags = {}
+      labels.each do |k, v|
+        @allowed_tags[k] = Regexp.compile('^(' + v.join('|') + ')$')
+      end
+      @allowed_tags
+    end
+
     def add_counter(name, description, instance_labels = [])
       @sinks.each { |x| x.add_counter("#{prefix}_#{name}", description, instance_labels) }
     end
@@ -109,15 +117,29 @@ def add_histogram(name, description, instance_labels = [], buckets = DEFAULT_BUC
     end
 
     def increment_counter(name, value = 1, tags = {})
+      return unless allowed?(tags)
       @sinks.each { |x| x.increment_counter("#{prefix}_#{name}", value, tags) }
     end
 
     def set_gauge(name, value, tags = {})
+      return unless allowed?(tags)
       @sinks.each { |x| x.set_gauge("#{prefix}_#{name}", value, tags) }
     end
 
     def observe_histogram(name, value, tags = {})
+      return unless allowed?(tags)
       @sinks.each { |x| x.observe_histogram("#{prefix}_#{name}", value, tags) }
     end
+
+    private
+
+    def allowed?(tags)
+      result = true
+      tags.each do |label, value|
+        regexp = @allowed_tags[label]
+        result &&= !!regexp.match(value) if regexp
+      end
+      result
+    end
   end
 end
diff --git a/lib/foreman/telemetry_sinks/prometheus_sink.rb b/lib/foreman/telemetry_sinks/prometheus_sink.rb
index b220c8dfd84..638a8286096 100644
--- a/lib/foreman/telemetry_sinks/prometheus_sink.rb
+++ b/lib/foreman/telemetry_sinks/prometheus_sink.rb
@@ -7,6 +7,8 @@ def initialize(opts = {})
       require 'prometheus/client/data_stores/direct_file_store'
       # Set multiprocess-friendly data store
       FileUtils.mkdir_p(PROMETHEUS_STORE_DIR)
+      # but clean it during startup as files will accumulate over time
+      FileUtils.rm_f(Dir.glob("#{PROMETHEUS_STORE_DIR}/*.bin"))
       Prometheus::Client.config.data_store =
         Prometheus::Client::DataStores::DirectFileStore.new(dir: PROMETHEUS_STORE_DIR)
       @prom = ::Prometheus::Client.registry