FEATURE: improve logging by including llm name (#640)

Log the language model name when logging api requests

app/models/ai_api_audit_log.rb

@@ -31,4 +31,5 @@ end
 #  topic_id             :integer
 #  post_id              :integer
 #  feature_name         :string(255)
+#  language_model       :string(255)
 #

db/migrate/20240527054218_add_language_model_to_ai_audit_logs.rb

@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+class AddLanguageModelToAiAuditLogs < ActiveRecord::Migration[7.0]
+  def change
+    add_column :ai_api_audit_logs, :language_model, :string, limit: 255
+  end
+end

lib/completions/endpoints/base.rb

@@ -120,6 +120,7 @@ module DiscourseAi
                   topic_id: dialect.prompt.topic_id,
                   post_id: dialect.prompt.post_id,
                   feature_name: feature_name,
+                  language_model: self.class.endpoint_name(@model),
                 )
 
               if !@streaming_mode

spec/lib/completions/endpoints/cohere_spec.rb

@@ -120,6 +120,8 @@ RSpec.describe DiscourseAi::Completions::Endpoints::Cohere do
     # billing should be picked
     expect(audit.request_tokens).to eq(17)
     expect(audit.response_tokens).to eq(22)
+
+    expect(audit.language_model).to eq("Cohere - command-r-plus")
   end
 
   it "is able to perform streaming completions" do