Allow 1 as true value in environment variables

lib/datadog/core/environment/variable_helpers.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Datadog
   module Core
     # Namespace for handling application environment
@@ -14,11 +16,17 @@ module VariableHelpers
         # @param [Boolean] default the default value if the keys in `var` are not present in the environment
         # @param [Boolean] deprecation_warning when `var` is a list, record a deprecation log when
         #   the first key in `var` is not used.
-        # @return [Boolean] if the environment value is the string `true`
+        # @return [Boolean] if the environment value is the string `true` or `1`
         # @return [default] if the environment value is not found
         def env_to_bool(var, default = nil, deprecation_warning: true)
           var = decode_array(var, deprecation_warning)
-          var && ENV.key?(var) ? ENV[var].to_s.strip.downcase == 'true' : default
+          if var && ENV.key?(var)
+            value = ENV[var].to_s.strip
+            value.downcase!
+            value == 'true' || value == '1' # rubocop:disable Style/MultipleComparison
+          else
+            default
+          end
         end
 
         # Reads an environment variable as an Integer.

spec/datadog/core/environment/variable_helpers_spec.rb

@@ -72,9 +72,10 @@
       %w[
         true
         TRUE
+        1
       ].each do |value|
         context value.to_s do
-          let(:env_value) { value.to_s }
+          let(:env_value) { value }
 
           it { is_expected.to be true }
         end
@@ -85,11 +86,11 @@
         '',
         'false',
         'FALSE',
-        0,
-        1
+        '0',
+        'arbitrary string',
       ].each do |value|
         context value.to_s do
-          let(:env_value) { value.to_s }
+          let(:env_value) { value }
 
           it { is_expected.to be false }
         end