feat: handle nested objects and arrays

Fixes logstash-plugins#24

CHANGELOG.md

@@ -1,3 +1,6 @@
+## next
+  - Add nested_objects configuration to parse nested object and arrays
+
 ## 3.3.2
   - Fix: avoid panic when handling very-large exponent-notation `_@timestamp` values [#71](https://github.com/logstash-plugins/logstash-input-gelf/pull/71)
 

docs/index.asciidoc

@@ -127,6 +127,14 @@ as an "additional" field, beginning with an underscore.
 
 e.g. `\_foo` becomes `foo`
 
+[id="plugins-{type}s-{plugin}-nested_objects"]
+===== `nested_objects`
+
+  * Value type is <<boolean,boolean>>
+  * Default value is `false`
+
+Whether or not to process dots in fields or leave them in place.
+
 
 
 

lib/logstash/inputs/gelf.rb

@@ -47,6 +47,9 @@ class LogStash::Inputs::Gelf < LogStash::Inputs::Base
   #
   config :strip_leading_underscore, :validate => :boolean, :default => true
 
+  # Whether or not to process dots in fields or leave them in place.
+  config :nested_objects, :validate => :boolean, :default => false
+
   RECONNECT_BACKOFF_SLEEP = 5
   TIMESTAMP_GELF_FIELD = "timestamp".freeze
   SOURCE_HOST_FIELD = "source_host".freeze
@@ -235,6 +238,7 @@ def self.new_event(json_gelf, host)
   def process_event(event)
     remap_gelf(event) if @remap
     strip_leading_underscore(event) if @strip_leading_underscore
+    handle_nested_objects(event) if @nested_objects
     decorate(event)
   end
 
@@ -293,4 +297,87 @@ def coerce_timestamp_carefully(value)
     value = BigDecimal(value) if value.kind_of?(String)
     self.class.coerce_timestamp(value)
   end
+
+  def handle_nested_objects(event)
+    base_target = event.to_hash
+    base_target.keys.each do |key|
+      next unless key.include? ?.
+      value = event.get(key)
+      previous_key = nil
+      first_key = nil
+      target = base_target
+
+      keys = key.split(".")
+      if key =~ /\.$/
+        keys.push("");
+      end
+
+      keys.each do |sub_key|
+        if previous_key.nil?
+          first_key = sub_key
+        else
+          #skip first sub_key
+          unless array_or_hash_has_element?(target, previous_key)
+            if key_is_number(sub_key)
+              set_in_array_or_hash(target, previous_key, Array.new)
+            else
+              set_in_array_or_hash(target, previous_key, Hash.new)
+            end
+          end
+          new_target = get_in_array_or_hash(target, previous_key)
+          if new_target.is_a?(Array) and !key_is_number(sub_key)
+            # key is not an integer, so we need to convert array to hash
+            new_target = Hash[new_target.map.with_index { |x, i| [i, x] }]
+            set_in_array_or_hash(target, previous_key, new_target)
+          end
+          target = new_target
+        end
+        previous_key = sub_key
+      end
+      set_in_array_or_hash(target, previous_key, value)
+      event.remove(key)
+      event.set(first_key, base_target[first_key])
+    end
+  rescue => e
+    @logger.warn("Failed to parse nested objects: #{e.message}")
+    event.tag("_nested_objects_failure")
+  end
+
+  def key_is_number(key)
+    key =~ /^\d+$/
+  end
+
+  def get_in_array_or_hash(container, key)
+    if container.is_a?(Array)
+      container[Integer(key)]
+    elsif container.is_a?(Hash)
+      container[key]
+    else
+      raise "not an array or hash"
+    end
+  end
+
+  def set_in_array_or_hash(container, key, value)
+    if container.is_a?(Array)
+      container[Integer(key)] = value
+    elsif container.is_a?(Hash)
+      container[key] = value
+    else
+      raise "not an array or hash"
+    end
+  end
+
+  def array_or_hash_has_element?(container, key)
+    if container.is_a?(Array)
+      if !key_is_number(key)
+        return false
+      else
+        !container[Integer(key)].nil?
+      end
+    elsif container.is_a?(Hash)
+      container.key?(key)
+    else
+      raise "not an array or hash"
+    end
+  end
 end

spec/inputs/gelf_spec.rb

@@ -238,4 +238,66 @@ def client_bootstrap(gelfclient, queue)
       end
     end
   end
+
+  describe "when handling complex messages" do
+    let(:host) { "127.0.0.1" }
+    let(:port) { 12211 }
+    let(:chunksize) { 1420 }
+    let(:gelfclient) { GELF::Notifier.new(host, port, chunksize) }
+
+    let(:config) { { "port" => port, "host" => host, "nested_objects" => true } }
+    let(:queue) { Queue.new }
+
+    subject(:gelf_input) { described_class.new(config) }
+
+    before(:each) do
+      subject.register
+      @runner = Thread.new { subject.run(queue) }
+
+      client_bootstrap(gelfclient, queue)
+    end
+
+    after(:each) do
+      subject.do_stop
+      @runner.kill
+      @runner.join
+    end
+
+    it "should accept hash fields using dot notation" do
+      gelfclient.notify!("short_message" => "test nested hash",
+                         "_toto.titi" => "objectValue",
+                         "_empty." => "pouet",
+      )
+      e = queue.pop
+      expect(e.get("toto")["titi"]).to eq("objectValue")
+      expect(e.get("empty")[""]).to eq("pouet")
+    end
+
+    it "should accept array fields using dot notation" do
+      gelfclient.notify!("short_message" => "test nested array",
+                         "_foo.0" => "first",
+                         "_foo.1" => "second",
+                         "_ca.0.titi" => "1",
+                         "_ca.1.titi" => "2",
+      )
+      e = queue.pop
+      expect(e.get("foo")).to eq(["first", "second"])
+      expect(e.get("ca")[0]["titi"]).to eq("1")
+      expect(e.get("ca")[1]["titi"]).to eq("2")
+    end
+
+    it "should accept hash looking like an array" do
+      gelfclient.notify!("short_message" => "test nested array",
+                         "_not_an_array.0" => "bob",
+                         "_not_an_array.1" => "alice",
+                         "_not_an_array.length" => "carol",
+      )
+      e = queue.pop
+      value = e.get("not_an_array")
+      expect(value).to be_a(Hash)
+      expect(value["0"]).to eq("bob")
+      expect(value["1"]).to eq("alice")
+      expect(value["length"]).to eq("carol")
+    end
+  end
 end