Add source headers to Synth calls (#1062)

app/models/provider/synth.rb

@@ -33,8 +33,7 @@ class Provider::Synth
 
   def fetch_exchange_rate(from:, to:, date:)
     retrying Provider::Base.known_transient_errors do |on_last_attempt|
-      response = Faraday.get("#{base_url}/rates/historical") do |req|
+      response = client.get("#{base_url}/rates/historical") do |req|
-        req.headers["Authorization"] = "Bearer #{api_key}"
         req.params["date"] = date.to_s
         req.params["from"] = from
         req.params["to"] = to
@@ -69,6 +68,22 @@ class Provider::Synth
       "https://api.synthfinance.com"
     end
 
+    def app_name
+      "maybe_app"
+    end
+
+    def app_type
+      Rails.application.config.app_mode
+    end
+
+    def client
+      @client ||= Faraday.new(url: base_url) do |faraday|
+        faraday.headers["Authorization"] = "Bearer #{api_key}"
+        faraday.headers["X-Source"] = app_name
+        faraday.headers["X-Source-Type"] = app_type
+      end
+    end
+
     def build_error(response)
       Provider::Base::ProviderError.new(<<~ERROR)
         Failed to fetch data from #{self.class}
@@ -78,7 +93,7 @@ class Provider::Synth
     end
 
     def fetch_page(url, page, params = {})
-      Faraday.get(url) do |req|
+      client.get(url) do |req|
         req.headers["Authorization"] = "Bearer #{api_key}"
         params.each { |k, v| req.params[k.to_s] = v.to_s }
         req.params["page"] = page

test/models/provider/synth_test.rb

@@ -17,18 +17,24 @@ class Provider::SynthTest < ActiveSupport::TestCase
   end
 
   test "retries then provides failed response" do
-    Faraday.expects(:get).returns(OpenStruct.new(success?: false)).times(3)
+    @client = mock
+    Faraday.stubs(:new).returns(@client)
 
-    response = @synth.fetch_exchange_rate from: "USD", to: "MXN", date: Date.current
+    @client.expects(:get).returns(OpenStruct.new(success?: false)).times(3)
+
+    response = @synth.fetch_exchange_rate from: "USD", to: "MXN", date: Date.iso8601("2024-08-01")
 
     assert_match "Failed to fetch data from Provider::Synth", response.error.message
   end
 
   test "retrying, then raising on network error" do
-    Faraday.expects(:get).raises(Faraday::TimeoutError).times(3)
+    @client = mock
+    Faraday.stubs(:new).returns(@client)
+
+    @client.expects(:get).raises(Faraday::TimeoutError).times(3)
 
     assert_raises Faraday::TimeoutError do
-      @synth.fetch_exchange_rate from: "USD", to: "MXN", date: Date.current
+      @synth.fetch_exchange_rate from: "USD", to: "MXN", date: Date.iso8601("2024-08-01")
     end
   end
 end