add max_log_length

Changelog.md

@@ -1,3 +1,9 @@
+# Changelog
+
+## 1.11.0
+
+* Add `max_log_length` to limit each log line length in order to prevent memory leaks in case of very long logs
+
 ## 1.10.0
 
 * Add an ability to insert Lamian's middleware inside the rails initialization process manually (`Lamian.config.middleware_autoset = true/false`)
@@ -14,7 +20,7 @@
 
 ## 1.3.0
 
-* Add support for the (new sentry gem)[https://github.com/getsentry/sentry-ruby].
+* Add support for the [new sentry gem](https://github.com/getsentry/sentry-ruby).
 
 ## 1.2.0
 
@@ -33,7 +39,6 @@ which ruins concept of single entry point :(. Also tied it to lamian instance
 
 * `8136689` fixed crashes when dump used outside lamian context
 
-
 ## 0.3.2
 
 * `e57e6cec` Changed rails dependency from `~> 4.2` to `>= 4.2`

lib/lamian/config.rb

@@ -13,12 +13,14 @@ module Lamian
   Config = Struct.new(
     :formatter,
     :max_log_lines,
+    :max_log_length,
     :raven_log_size_limit,
     :middleware_autoset,
   ) do
     def initialize
       self.formatter = ::Logger::Formatter.new
       self.max_log_lines = 5000
+      self.max_log_length = 10_000
       self.raven_log_size_limit = 500_000
       self.middleware_autoset = true
     end

lib/lamian/log_device.rb

@@ -2,14 +2,16 @@
 
 module Lamian
   class LogDevice # :nodoc:
-    def initialize(size = Lamian.config.max_log_lines)
-      self.size = size
+    def initialize(max_log_lines: Lamian.config.max_log_lines,
+                   max_log_length: Lamian.config.max_log_length)
+      self.max_log_lines = max_log_lines
+      self.max_log_length = max_log_length
       self.lines = []
     end
 
-    def write(string) # :nodoc:
-      lines << string
-      lines.shift if lines.size > size
+    def write(msg) # :nodoc:
+      lines << truncate(msg)
+      lines.shift if lines.size > max_log_lines
       true
     end
 
@@ -19,6 +21,15 @@ def string # :nodoc:
 
     private
 
-    attr_accessor :size, :lines
+    attr_accessor :lines, :max_log_lines, :max_log_length
+
+    def truncate(msg)
+      return msg unless msg.size > max_log_length
+
+      suffix = "..."
+      msg = msg[0, max_log_length - suffix.size]
+
+      "#{msg}#{suffix}"
+    end
   end
 end

spec/lamian/log_device_spec.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 describe Lamian::LogDevice do
-  subject(:logdev) { described_class.new(5) }
+  subject(:logdev) { described_class.new(max_log_lines: 5, max_log_length: 20) }
 
   it "saves log" do
     logdev.write("Hello ")
@@ -13,4 +13,9 @@
     8.times { |x| logdev.write(x + 1) }
     expect(logdev.string).to eq("45678")
   end
+
+  it "truncates long lines" do
+    logdev.write("Hello world, this is me!")
+    expect(logdev.string).to eq("Hello world, this...")
+  end
 end