Merge pull request #1 from launchdarkly/event-processing

Event processing

Author: jkodumal

README.md

@@ -4,10 +4,15 @@ LaunchDarkly SDK for Ruby
 Quick setup
 -----------
 
-1. Install the Ruby SDK with `gem`
+0. Install the Ruby SDK with `gem`
 
         gem install ldclient-rb
 
+1. Require the LaunchDarkly client:
+
+        require 'ldclient-rb'
+
+
 2. Create a new LDClient with your API key:
 
         client = LaunchDarkly::LDClient.new("your_api_key")

lib/ldclient-rb/config.rb

@@ -1,15 +1,102 @@
+require 'logger'
+
 module LaunchDarkly
+
+  # 
+  # This class exposes advanced configuration options for the LaunchDarkly client library. Most users
+  # will not need to use a custom configuration-- the default configuration sets sane defaults for most use cases. 
+  # 
+  #   
   class Config
-    def initialize(base_uri)
-      @base_uri = base_uri
+    # 
+    # Constructor for creating custom LaunchDarkly configurations. 
+    # 
+    # @param opts [Hash] the configuration options
+    # @option opts [Logger] :logger A logger to use for messages from the LaunchDarkly client. Defaults to the Rails logger in a Rails environment, or stdout otherwise.
+    # @option opts [String] :base_uri ("https://app.launchdarkly.com") The base URL for the LaunchDarkly server. Most users should use the default value.
+    # @option opts [Integer] :capacity (10000) The capacity of the events buffer. The client buffers up to this many events in memory before flushing. If the capacity is exceeded before the buffer is flushed, events will be discarded.
+    # @option opts [Integer] :flush_interval (30) The number of seconds between flushes of the event buffer. 
+    # @option opts [Object] :store A cache store for the Faraday HTTP caching library. Defaults to the Rails cache in a Rails environment, or a thread-safe in-memory store otherwise.
+    # 
+    # @return [type] [description]
+    def initialize(opts = {})
+      @base_uri = opts[:base_uri] || Config.default_base_uri
+      @capacity = opts[:capacity] || Config.default_capacity
+      @logger = opts[:logger] || Config.default_logger
+      @store = opts[:store] || Config.default_store
+      @flush_interval = opts[:flush_interval] || Config.default_flush_interval
     end
 
+    # 
+    # The base URL for the LaunchDarkly server.
+    # 
+    # @return [String] The configured base URL for the LaunchDarkly server.
     def base_uri
       @base_uri
     end
 
+    # 
+    # The number of seconds between flushes of the event buffer. Decreasing the flush interval means
+    # that the event buffer is less likely to reach capacity.
+    # 
+    # @return [Integer] The configured number of seconds between flushes of the event buffer.
+    def flush_interval
+      @flush_interval
+    end
+
+    # 
+    # The configured logger for the LaunchDarkly client. The client library uses the log to
+    # print warning and error messages. 
+    # 
+    # @return [Logger] The configured logger
+    def logger
+      @logger
+    end
+
+    # 
+    # The capacity of the events buffer. The client buffers up to this many events in memory before flushing. If the capacity is exceeded before the buffer is flushed, events will be discarded.
+    # Increasing the capacity means that events are less likely to be discarded, at the cost of consuming more memory.
+    # 
+    # @return [Integer] The configured capacity of the event buffer
+    def capacity
+      @capacity
+    end
+
+    # 
+    # The store for the Faraday HTTP caching library. Stores should respond to 'read' and 'write' requests.
+    # 
+    # @return [Object] The configured store for the Faraday HTTP caching library.
+    def store
+      @store
+    end
+
+    # 
+    # The default LaunchDarkly client configuration. This configuration sets reasonable defaults for most users.
+    # 
+    # @return [Config] The default LaunchDarkly configuration.
     def self.default
-      Config.new('https://app.launchdarkly.com')
+      Config.new()
     end
+
+    def self.default_capacity
+      10000
+    end
+
+    def self.default_base_uri
+      "https://app.launchdarkly.com"
+    end
+
+    def self.default_store
+      defined?(Rails) && Rails.respond_to?(:cache) ? Rails.cache : ThreadSafeMemoryStore.new
+    end    
+
+    def self.default_flush_interval
+      30
+    end
+
+    def self.default_logger
+      defined?(Rails) && Rails.respond_to?(:logger) ? Rails.logger : ::Logger.new($stdout)
+    end
+
   end
 end

lib/ldclient-rb/ldclient.rb

@@ -1,26 +1,130 @@
 require 'faraday/http_cache'
 require 'json'
 require 'digest/sha1'
+require 'thread'
+require 'logger'
 
 module LaunchDarkly
+  # 
+  # A client for the LaunchDarkly API. Client instances are thread-safe. Users 
+  # should create a single client instance for the lifetime of the application.
+  # 
+  # 
   class LDClient
 
-    LONG_SCALE = Float(0xFFFFFFFFFFFFFFF) 
-    
+    # 
+    # Creates a new client instance that connects to LaunchDarkly. A custom
+    # configuration parameter can also supplied to specify advanced options,
+    # but for most use cases, the default configuration is appropriate.
+    # 
+    # 
+    # @param api_key [String] the API key for your LaunchDarkly account
+    # @param config [Config] an optional client configuration object
+    # 
+    # @return [LDClient] The LaunchDarkly client instance
     def initialize(api_key, config = Config.default)
-      store = ThreadSafeMemoryStore.new
+      @queue = Queue.new
       @api_key = api_key
       @config = config
       @client = Faraday.new do |builder|
-        builder.use :http_cache, store: store
+        builder.use :http_cache, store: @config.store
 
         builder.adapter Faraday.default_adapter
       end
+
+      Thread.new do
+        while true do
+          events = []
+          num_events = @queue.length()
+          num_events.times do 
+            events << @queue.pop()
+          end
+
+          if !events.empty?()
+            res =
+            @client.post (@config.base_uri + "/api/events/bulk") do |req|
+              req.headers['Authorization'] = 'api_key ' + @api_key
+              req.headers['User-Agent'] = 'RubyClient/' + LaunchDarkly::VERSION
+              req.headers['Content-Type'] = 'application/json'
+              req.body = events.to_json
+            end
+            if res.status != 200
+              @config.logger.error("Unexpected status code while processing events: " + res.status)
+            end
+          end
+
+          sleep(@config.flush_interval)
+        end
+      end
+
     end
 
+    # 
+    # Calculates the value of a feature flag for a given user. At a minimum, the user hash
+    # should contain a +:key+ .
+    # 
+    # @example Basic user hash
+    #      {:key => "user@example.com"}
+    # 
+    # For authenticated users, the +:key+ should be the unique identifier for your user. For anonymous users,
+    # the +:key+ should be a session identifier or cookie. In either case, the only requirement is that the key
+    # is unique to a user. 
+    # 
+    # You can also pass IP addresses and country codes in the user hash.
+    # 
+    # @example More complete user hash
+    #      {:key => "user@example.com", :ip => "127.0.0.1", :country => "US"}
+    # 
+    # Countries should be sent as ISO 3166-1 alpha-2 codes.
+    # 
+    # The user hash can contain arbitrary custom attributes stored in a +:custom+ sub-hash:
+    # 
+    # @example A user hash with custom attributes
+    #      {:key => "user@example.com", :custom => {:customer_rank => 1000, :groups => ["google", "microsoft"]}} 
+    # 
+    # Attribute values in the custom hash can be integers, booleans, strings, or lists of integers, booleans, or strings.
+    # 
+    # @param key [String] the unique feature key for the feature flag, as shown on the LaunchDarkly dashboard
+    # @param user [Hash] a hash containing parameters for the end user requesting the flag
+    # @param default=false [Boolean] the default value of the flag
+    # 
+    # @return [Boolean] whether or not the flag should be enabled, or the default value if the flag is disabled on the LaunchDarkly control panel
     def get_flag?(key, user, default=false)
+      begin
+        value = get_flag_int(key, user, default)
+        add_event({:kind => 'feature', :key => key, :user => user, :value => value})
+        return value
+      rescue StandardError => error
+        @config.logger.error("Unhandled exception in get_flag: " + error.message)
+        default
+      end
+    end
+
+    def add_event(event)
+      if @queue.length() < @config.capacity
+        event[:creationDate] = (Time.now.to_f * 1000).to_i
+        @queue.push(event)
+      else
+        @config.logger.warn("Exceeded event queue capacity. Increase capacity to avoid dropping events.")
+      end
+    end
+
+    # 
+    # Tracks that a user performed an event
+    # 
+    # @param event_name [String] The name of the event
+    # @param user [Hash] The user that performed the event. This should be the same user hash used in calls to {#get_flag?}
+    # @param data [Hash] A hash containing any additional data associated with the event
+    # 
+    # @return [void]
+    def send_event(event_name, user, data)
+      add_event({:kind => 'custom', :key => event_name, :user => user, :data => data })
+    end
+
+    def get_flag_int(key, user, default)
 
       unless user
+        @config.logger.error("Must specify user")
         return default
       end
 
@@ -30,51 +134,68 @@ def get_flag?(key, user, default=false)
         req.headers['User-Agent'] = 'RubyClient/' + LaunchDarkly::VERSION
       end
 
-      feature = JSON.parse(res.body)
+      if res.status == 401
+        @config.logger.error("Invalid API key")
+        return default
+      end
+
+      if res.status == 404
+        @config.logger.error("Unknown feature key: " + key)
+        return default
+      end
+
+      if res.status != 200
+        @config.logger.error("Unexpected status code " + res.status)
+        return default
+      end
+
+
+      feature = JSON.parse(res.body, :symbolize_names => true)
 
       val = evaluate(feature, user)
 
       val == nil ? default : val
     end
 
     def param_for_user(feature, user)
-      if user.has_key? 'key' 
-        id_hash = user['key']
+      if user.has_key? :key 
+        id_hash = user[:key]
       else
         return nil
       end
 
-      if user.has_key? 'secondary'
-        id_hash += '.' + user['secondary']
+      if user.has_key? :secondary
+        id_hash += '.' + user[:secondary]
       end
 
-      hash_key = "%s.%s.%s" % [feature['key'], feature['salt'], id_hash]
+      hash_key = "%s.%s.%s" % [feature[:key], feature[:salt], id_hash]
+
       hash_val = (Digest::SHA1.hexdigest(hash_key))[0..14]
-      return hash_val.to_i(16) / LONG_SCALE
+      return hash_val.to_i(16) / Float(0xFFFFFFFFFFFFFFF)
     end
 
     def match_target?(target, user)
-      attrib = target['attribute']
+      attrib = target[:attribute].to_sym
 
-      if attrib == 'key' or attrib == 'ip' or attrib == 'country'
+      if attrib == :key or attrib == :ip or attrib == :country
         if user[attrib]
           u_value = user[attrib]
-          return target['values'].include? u_value
+          return target[:values].include? u_value
         else
           return false
         end
       else # custom attribute
-        unless user.has_key? 'custom'
+        unless user.has_key? :custom
           return false
         end
-        unless user['custom'].include? attrib
+        unless user[:custom].include? attrib
           return false
         end
-        u_value = user['custom'][attrib]
+        u_value = user[:custom][attrib]
         if u_value.is_a? String or u_value.is_a? Numeric
-          return target['values'].include? u_value
+          return target[:values].include? u_value
         elsif u_value.is_a? Array
-          return ! ((target['values'] & u_value).empty?)
+          return ! ((target[:values] & u_value).empty?)
         end
 
         return false     
@@ -83,7 +204,7 @@ def match_target?(target, user)
     end
 
     def match_variation?(variation, user)
-      variation['targets'].each do |target|
+      variation[:targets].each do |target|
         if match_target?(target, user)
           return true
         end
@@ -92,7 +213,7 @@ def match_variation?(variation, user)
     end
 
     def evaluate(feature, user)
-      unless feature['on']
+      unless feature[:on]
         return nil
       end
 
@@ -102,26 +223,26 @@ def evaluate(feature, user)
         return nil
       end
 
-      feature['variations'].each do |variation|
+      feature[:variations].each do |variation|
         if match_variation?(variation, user)
-          return variation['value']
+          return variation[:value]
         end
       end
 
       total = 0.0
-      feature['variations'].each do |variation|
-        total += variation['weight'].to_f / 100.0
+      feature[:variations].each do |variation|
+        total += variation[:weight].to_f / 100.0
 
         if param < total
-          return variation['value']
+          return variation[:value]
         end
       end
 
       return nil
 
     end
 
-    private :param_for_user, :match_target?, :match_variation?, :evaluate
+    private :add_event, :get_flag_int, :param_for_user, :match_target?, :match_variation?, :evaluate
 
 
   end