1 files changed, 83 insertions, 0 deletions
diff --git a/src/email/email_server.rb b/src/email/email_server.rb
new file mode 100644
index 0000000..98a5259
--- /dev/null
+++ b/src/email/email_server.rb
@@ -0,0 +1,83 @@
+# Copyright The OpenTelemetry Authors
+# SPDX-License-Identifier: Apache-2.0
+
+require "ostruct"
+require "pony"
+require "sinatra"
+require "open_feature/sdk"
+require "openfeature/flagd/provider"
+# require "open_feature/flagd_provider"
+
+require "opentelemetry/sdk"
+require "opentelemetry/exporter/otlp"
+require "opentelemetry/instrumentation/sinatra"
+
+set :port, ENV["EMAIL_PORT"]
+
+# Initialize OpenFeature SDK with flagd provider
+flagd_client = OpenFeature::Flagd::Provider.build_client
+flagd_client.configure do |config|
+  config.host = ENV.fetch("FLAGD_HOST", "localhost")
+  config.port = ENV.fetch("FLAGD_PORT", 8013).to_i
+  config.tls = ENV.fetch("FLAGD_TLS", "false") == "true"
+end
+
+OpenFeature::SDK.configure do |config|
+  config.set_provider(flagd_client)
+end
+
+OpenTelemetry::SDK.configure do |c|
+  c.use "OpenTelemetry::Instrumentation::Sinatra"
+end
+
+post "/send_order_confirmation" do
+  data = JSON.parse(request.body.read, object_class: OpenStruct)
+
+  # get the current auto-instrumented span
+  current_span = OpenTelemetry::Trace.current_span
+  current_span.add_attributes({
+    "app.order.id" => data.order.order_id,
+  })
+
+  send_email(data)
+
+end
+
+error do
+  OpenTelemetry::Trace.current_span.record_exception(env['sinatra.error'])
+end
+
+def send_email(data)
+  # create and start a manual span
+  tracer = OpenTelemetry.tracer_provider.tracer('email')
+  tracer.in_span("send_email") do |span|
+    # Check if memory leak flag is enabled
+    client = OpenFeature::SDK.build_client
+    memory_leak_multiplier = client.fetch_number_value(flag_key: "emailMemoryLeak", default_value: 0)
+
+    # To speed up the memory leak we create a long email body
+    confirmation_content = erb(:confirmation, locals: { order: data.order })
+    whitespace_length = [0, confirmation_content.length * (memory_leak_multiplier-1)].max
+
+    Pony.mail(
+      to:       data.email,
+      from:     "noreply@example.com",
+      subject:  "Your confirmation email",
+      body:     confirmation_content + " " * whitespace_length,
+      via:      :test
+    )
+
+    # If not clearing the deliveries, the emails will accumulate in the test mailer
+    # We use this to create a memory leak.
+    if memory_leak_multiplier < 1
+      Mail::TestMailer.deliveries.clear
+    end
+
+    span.set_attribute("app.email.recipient", data.email)
+    puts "Order confirmation email sent to: #{data.email}"
+  end
+  # manually created spans need to be ended
+  # in Ruby, the method `in_span` ends it automatically
+  # check out the OpenTelemetry Ruby docs at: 
+  # https://opentelemetry.io/docs/instrumentation/ruby/manual/#creating-new-spans 
+end