From 17f7704c1d26cd712350b07cd8d646b26060c807 Mon Sep 17 00:00:00 2001
From: Stephen Hulme <sh51@sanger.ac.uk>
Date: Tue, 24 Mar 2026 09:53:46 +0000
Subject: [PATCH 1/2] fix: add request logger middleware

---
 config/initializers/request_logger.rb | 11 ++++
 lib/middleware/request_logger.rb      | 87 +++++++++++++++++++++++++++
 2 files changed, 98 insertions(+)
 create mode 100644 config/initializers/request_logger.rb
 create mode 100644 lib/middleware/request_logger.rb

diff --git a/config/initializers/request_logger.rb b/config/initializers/request_logger.rb
new file mode 100644
index 00000000..3a94825a
--- /dev/null
+++ b/config/initializers/request_logger.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+require_relative '../../lib/middleware/request_logger'
+
+Rails.application.configure do
+  # Insert RequestLogger near the top, before Rails::Rack::Logger
+  config.middleware.insert_before(Rails::Rack::Logger, Middleware::RequestLogger)
+end
+
+# Add backtrace silencers for middleware so that we don't see it in backtraces.
+Rails.backtrace_cleaner.add_silencer { |line| line.include?('request_logger') }
diff --git a/lib/middleware/request_logger.rb b/lib/middleware/request_logger.rb
new file mode 100644
index 00000000..d2ad7bd9
--- /dev/null
+++ b/lib/middleware/request_logger.rb
@@ -0,0 +1,87 @@
+# frozen_string_literal: true
+
+module Middleware
+  # Log request and response details for monitoring and high-level profiling.
+  #
+  # @param log_level [Symbol] the log level to use for logging requests (default: :info)
+  # @param environment_context [Hash] additional context to include in log entries, such as host and version information
+  #
+  # Returns a JSON parseable log entry like:
+  # [INFO] [RequestLogger] {"method":"GET","path":"/samples/1234","format":"html","status_code":200,
+  #   "status_message":"OK","duration_ms":935,"client_ip":"172.21.43.210",
+  #   "request_id":"9fd18098-dea3-46f0-83c8-c41852441db3","tags":["request","success"],
+  #   "@timestamp":"2026-02-12T12:10:50.284+00:00"}
+  class RequestLogger
+    def initialize(app, log_level: :info, environment_context: nil)
+      @app = app
+      @log_level = log_level
+      @environment_context = environment_context
+    end
+
+    def call(env)
+      response, elapsed_ms = elapsed_milliseconds { @app.call(env) }
+
+      request = ActionDispatch::Request.new(env)
+      log_request(request, response, elapsed_ms)
+
+      response
+    end
+
+    private
+
+    # Get the current clock time using the Rack::Runtime clock
+    def clock_time
+      Rack::Utils.clock_time
+    end
+
+    def elapsed_milliseconds
+      start_time = clock_time
+      result = yield
+      end_time = clock_time
+
+      elapsed_ms = ((end_time - start_time) * 1000).round
+      [result, elapsed_ms]
+    end
+
+    def tag_for_status(status_code)
+      case status_code
+      when 100..199 then 'informational'
+      when 200..299 then 'success'
+      when 300..399 then 'redirection'
+      when 400..499 then 'client_error'
+      when 500..599 then 'server_error'
+      end
+    end
+
+    def tags(status_code)
+      tags = ['request']
+      tags << tag_for_status(status_code)
+      tags.compact!
+      tags
+    end
+
+    def log_request(request, response, elapsed_ms) # rubocop:disable Metrics/AbcSize
+      status_code, _headers, _body = response
+
+      status_message = Rack::Utils::HTTP_STATUS_CODES[status_code] || 'Unknown Status'
+      timestamp = Time.zone.now.iso8601(3)
+
+      record = {
+        method: request.request_method,
+        url: request.fullpath,
+        path: request.path,
+        format: request.format.symbol,
+        status_code: status_code,
+        status_message: status_message,
+        duration_ms: elapsed_ms,
+        client_ip: request.remote_ip,
+        request_id: request.request_id,
+        tags: tags(status_code),
+        '@timestamp': timestamp
+      }
+      record.merge!(@environment_context) if @environment_context.present?
+
+      Rails.logger.public_send(@log_level, "[RequestLogger] #{record.to_json}")
+    end
+  end
+end

From 59aea60bcd92df1e7182444edda2498651c600ab Mon Sep 17 00:00:00 2001
From: Stephen Hulme <sh51@sanger.ac.uk>
Date: Tue, 24 Mar 2026 10:11:39 +0000
Subject: [PATCH 2/2] style: lint

---
 lib/middleware/request_logger.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/middleware/request_logger.rb b/lib/middleware/request_logger.rb
index d2ad7bd9..5942cbc1 100644
--- a/lib/middleware/request_logger.rb
+++ b/lib/middleware/request_logger.rb
@@ -60,7 +60,7 @@ def tags(status_code)
       tags
     end
 
-    def log_request(request, response, elapsed_ms) # rubocop:disable Metrics/AbcSize
+    def log_request(request, response, elapsed_ms) # rubocop:disable Metrics/AbcSize,Metrics/MethodLength
       status_code, _headers, _body = response
 
       status_message = Rack::Utils::HTTP_STATUS_CODES[status_code] || 'Unknown Status'