WIP: Strategies for dealing with label errors, other than just raising

lib/prometheus/client/config.rb

@@ -6,9 +6,11 @@ module Prometheus
   module Client
     class Config
       attr_accessor :data_store
+      attr_accessor :label_error_strategy
 
       def initialize
         @data_store = Prometheus::Client::DataStores::SimpleHash.new
+        @label_error_strategy = ErrorStrategies::Raise # we'll have a custom one, off-gem for Raven (or we can provide that one by default), and set it to that in production
       end
     end
   end

lib/prometheus/client/counter.rb

@@ -14,7 +14,7 @@ def increment(by: 1, labels: {})
         raise ArgumentError, 'increment must be a non-negative number' if by < 0
 
         label_set = label_set_for(labels)
-        @store.increment(labels: label_set, by: by)
+        @store.increment(labels: label_set, by: by) if label_set
       end
     end
   end

lib/prometheus/client/error_strategies/raise.rb

@@ -0,0 +1,7 @@
+module ErrorStrategies
+  class Raise
+    def self.label_error(exception_klass, message)
+      raise exception_klass, message
+    end
+  end
+end

lib/prometheus/client/gauge.rb

@@ -17,21 +17,22 @@ def set(value, labels: {})
           raise ArgumentError, 'value must be a number'
         end
 
-        @store.set(labels: label_set_for(labels), val: value)
+        label_set = label_set_for(labels)
+        @store.set(labels: label_set, val: value) if label_set
       end
 
       # Increments Gauge value by 1 or adds the given value to the Gauge.
       # (The value can be negative, resulting in a decrease of the Gauge.)
       def increment(by: 1, labels: {})
         label_set = label_set_for(labels)
-        @store.increment(labels: label_set, by: by)
+        @store.increment(labels: label_set, by: by) if label_set
       end
 
       # Decrements Gauge value by 1 or subtracts the given value from the Gauge.
       # (The value can be negative, resulting in a increase of the Gauge.)
       def decrement(by: 1, labels: {})
         label_set = label_set_for(labels)
-        @store.increment(labels: label_set, by: -by)
+        @store.increment(labels: label_set, by: -by) if label_set
       end
     end
   end

lib/prometheus/client/histogram.rb

@@ -48,6 +48,7 @@ def type
 
       def observe(value, labels: {})
         base_label_set = label_set_for(labels)
+        return unless base_label_set
 
         @store.synchronize do
           buckets.each do |upper_limit|

lib/prometheus/client/label_set_validator.rb

@@ -18,7 +18,6 @@ class ReservedLabelError < LabelSetError; end
       def initialize(expected_labels:, reserved_labels: [])
         @expected_labels = expected_labels.sort
         @reserved_labels = BASE_RESERVED_LABELS + reserved_labels
-        @validated = {}
       end
 
       def valid?(labels)
@@ -34,17 +33,17 @@ def valid?(labels)
       end
 
       def validate(labels)
-        return labels if @validated.key?(labels.hash)
-
         valid?(labels)
 
         unless keys_match?(labels)
           raise InvalidLabelSetError, "labels must have the same signature " \
                                       "(keys given: #{labels.keys.sort} vs." \
                                       " keys expected: #{expected_labels}"
+
+          return false
         end
 
-        @validated[labels.hash] = labels
+        labels
       end
 
       private
@@ -73,3 +72,7 @@ def validate_reserved_key(key)
     end
   end
 end
+
+
+# Replace all of these Raises for
+# `Prometheus::Client.config.label_error_strategy.label_error(ExceptionClass, "errMessage")`

lib/prometheus/client/summary.rb

@@ -14,6 +14,7 @@ def type
       # Records a given value.
       def observe(value, labels: {})
         base_label_set = label_set_for(labels)
+        return unless base_label_set
 
         @store.synchronize do
           @store.increment(labels: base_label_set.merge(quantile: "count"), by: 1)