added a Rack logger middleware

lib/couchrest/middlewares/logger.rb

@@ -0,0 +1,263 @@
+####################################
+# USAGE
+#
+# in your rack.rb file
+# require this file and then:
+#
+# couch = CouchRest.new
+# LOG_DB = couch.database!('couchrest-logger')
+# use CouchRest::Logger, LOG_DB
+# 
+# Note:
+# to require just this middleware, if you have the gem installed do:
+# require 'couchrest/middlewares/logger'
+#
+# For log processing examples, see examples at the bottom of this file
+
+module CouchRest
+  class Logger 
+    
+    def self.log
+      Thread.current["couchrest.logger"] ||= {:queries => []}
+    end
+        
+    def initialize(app, db=nil)
+      @app = app
+      @db = db
+    end
+    
+    def self.record(log_info)
+      log[:queries] << log_info
+    end
+    
+    def log
+      Thread.current["couchrest.logger"] ||= {:queries => []}
+    end
+    
+    def reset_log
+      Thread.current["couchrest.logger"] = nil
+    end
+ 
+    def call(env)
+      reset_log
+      log['started_at'] = Time.now
+      log['env'] = env
+      log['url'] = 'http://' + env['HTTP_HOST'] + env['REQUEST_URI'] 
+      response = @app.call(env)
+      log['ended_at'] = Time.now
+      log['duration'] = log['ended_at'] - log['started_at']
+      # let's report the log in a different thread so we don't slow down the app
+      @db ? Thread.new(@db, log){|db, rlog| db.save_doc(rlog);} : p(log.inspect)
+      response
+    end
+  end
+end
+
+# inject our logger into CouchRest HTTP abstraction layer
+module HttpAbstraction
+ 
+  def self.get(uri, headers=nil)
+    start_query = Time.now
+    log = {:method => :get, :uri => uri, :headers => headers}
+    response = super(uri, headers=nil)
+    end_query = Time.now
+    log[:duration] = (end_query - start_query)
+    CouchRest::Logger.record(log)
+    response
+  end 
+  
+  def self.post(uri, payload, headers=nil)
+    start_query = Time.now
+    log = {:method => :post, :uri => uri, :payload =>  (payload ? (JSON.load(payload) rescue 'parsing error') : nil), :headers => headers}
+    response = super(uri, payload, headers=nil)
+    end_query = Time.now
+    log[:duration] = (end_query - start_query)
+    CouchRest::Logger.record(log)
+    response
+  end
+   
+  def self.put(uri, payload, headers=nil)
+    start_query = Time.now
+    log = {:method => :put, :uri => uri, :payload => (payload ? (JSON.load(payload) rescue 'parsing error') : nil), :headers => headers}
+    response = super(uri, payload, headers=nil)
+    end_query = Time.now
+    log[:duration] = (end_query - start_query)
+    CouchRest::Logger.record(log)
+    response
+  end
+  
+  def self.delete(uri, headers=nil)
+    start_query = Time.now
+    log = {:method => :delete, :uri => uri, :headers => headers}
+    response = super(uri, headers=nil)
+    end_query = Time.now
+    log[:duration] = (end_query - start_query)
+    CouchRest::Logger.record(log)
+    response
+  end   
+  
+end 
+
+
+# Advanced usage example 
+#
+#
+# # DB VIEWS 
+# by_url = {
+#   :map => 
+#     "function(doc) {
+#       if(doc['url']){ emit(doc['url'], 1) };
+#     }",
+#  :reduce => 
+#     'function (key, values, rereduce) {
+#        return(sum(values));
+#     };'
+# }
+# req_duration = {
+#   :map => 
+#     "function(doc) {
+#       if(doc['duration']){ emit(doc['url'], doc['duration']) };
+#     }",
+#  :reduce => 
+#     'function (key, values, rereduce) {
+#        return(sum(values)/values.length);
+#     };'
+# }
+# 
+# query_duration = {
+#   :map => 
+#     "function(doc) {
+#           if(doc['queries']){ 
+#             doc.queries.forEach(function(query){
+#     if(query['duration'] && query['method']){ 
+#               emit(query['method'], query['duration'])
+#     }
+#             });
+#           };
+#          }" ,
+#    :reduce => 
+#       'function (key, values, rereduce) {
+#         return(sum(values)/values.length);
+#       };'
+# }
+# 
+# action_queries = {
+#   :map => 
+#     "function(doc) {
+#           if(doc['queries']){
+#              emit(doc['url'], doc['queries'].length)
+#           };
+#          }",
+#  :reduce => 
+#     'function (key, values, rereduce) {
+#       return(sum(values)/values.length);
+#     };'
+# }  
+# 
+# action_time_spent_in_db = {
+#   :map => 
+#     "function(doc) {
+#           if(doc['queries']){
+#             var totalDuration = 0;
+#             doc.queries.forEach(function(query){
+#               totalDuration += query['duration']
+#             })
+#              emit(doc['url'], totalDuration)
+#           };
+#          }",
+#  :reduce => 
+#     'function (key, values, rereduce) {
+#       return(sum(values)/values.length);
+#     };'
+# }
+# 
+# show_queries =  %Q~function(doc, req) {
+#                    var body = ""
+#                    body += "<h1>" + doc['url'] + "</h1>"
+#                    body += "<h2>Request duration in seconds: " + doc['duration'] + "</h2>"
+#                    body += "<h3>" + doc['queries'].length + " queries</h3><ul>"
+#                    if (doc.queries){
+#                      doc.queries.forEach(function(query){
+#                        body += "<li>"+ query['uri'] +"</li>"
+#                      });
+#                    };
+#                    body += "</ul>"
+#                    if(doc){ return { body: body} }
+#                  }~
+# 
+# 
+# couch = CouchRest.new
+# LOG_DB = couch.database!('couchrest-logger')   
+# design_doc = LOG_DB.get("_design/stats") rescue nil
+# LOG_DB.delete_doc design_doc rescue nil
+# LOG_DB.save_doc({
+#   "_id" => "_design/stats",
+#   :views => {
+#     :by_url           => by_url,
+#     :request_duration => req_duration,
+#     :query_duration   => query_duration,
+#     :action_queries   => action_queries,
+#     :action_time_spent_in_db => action_time_spent_in_db
+#   },
+#  :shows => {
+#    :queries => show_queries
+#  }
+# })
+# 
+# module CouchRest
+#   class Logger
+#     
+#     def self.roundup(value)
+#       begin
+#         value = Float(value)
+#         (value * 100).round.to_f / 100
+#       rescue
+#         value
+#       end
+#     end
+#     
+#     # Usage example:
+#     # CouchRest::Logger.average_request_duration(LOG_DB)['rows'].first['value']
+#     def self.average_request_duration(db)
+#       raw = db.view('stats/request_duration', :reduce => true)
+#       (raw.has_key?('rows') && !raw['rows'].empty?) ? roundup(raw['rows'].first['value']) : 'not available yet'
+#     end
+#     
+#     def self.average_query_duration(db)
+#       raw =  db.view('stats/query_duration', :reduce => true)
+#       (raw.has_key?('rows') && !raw['rows'].empty?) ? roundup(raw['rows'].first['value']) : 'not available yet'
+#     end   
+#     
+#     def self.average_get_query_duration(db)
+#       raw = db.view('stats/query_duration', :key => 'get', :reduce => true)
+#       (raw.has_key?('rows') && !raw['rows'].empty?) ? roundup(raw['rows'].first['value']) : 'not available yet'
+#     end  
+#     
+#     def self.average_post_query_duration(db)
+#       raw = db.view('stats/query_duration', :key => 'post', :reduce => true)
+#       (raw.has_key?('rows') && !raw['rows'].empty?) ? roundup(raw['rows'].first['value']) : 'not available yet'
+#     end 
+#     
+#     def self.average_queries_per_action(db)
+#       raw = db.view('stats/action_queries', :reduce => true)
+#       (raw.has_key?('rows') && !raw['rows'].empty?) ? roundup(raw['rows'].first['value']) : 'not available yet'
+#     end
+#     
+#     def self.average_db_time_per_action(db)
+#      raw = db.view('stats/action_time_spent_in_db', :reduce => true)
+#      (raw.has_key?('rows') && !raw['rows'].empty?) ? roundup(raw['rows'].first['value']) : 'not available yet'
+#     end
+#     
+#     def self.stats(db)
+#       Thread.new(db){|db|
+#         puts "===  STATS  ===\n"
+#         puts "average request duration: #{average_request_duration(db)}\n"
+#         puts "average query duration: #{average_query_duration(db)}\n"
+#         puts "average queries per action : #{average_queries_per_action(db)}\n"
+#         puts "average time spent in DB (per action): #{average_db_time_per_action(db)}\n"
+#         puts "===============\n"   
+#      }
+#     end
+#     
+#   end
+# end