From 8d6873ecbadd57e8dafd0f53c5a676a527dce5e2 Mon Sep 17 00:00:00 2001
From: Jon Philpott <jon.philpott@mx.com>
Date: Tue, 8 Nov 2022 15:24:56 -0700
Subject: [PATCH] add ability to prefix log lines with a.. prefix.

---
 lib/logstasher.rb                      |  3 ++-
 lib/logstasher/railtie.rb              |  2 ++
 spec/lib/logstasher/logstasher_spec.rb | 13 +++++++++++++
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/lib/logstasher.rb b/lib/logstasher.rb
index 26da3a5..15522a9 100644
--- a/lib/logstasher.rb
+++ b/lib/logstasher.rb
@@ -9,6 +9,7 @@ class << self
     attr_writer :serialize_parameters
     attr_writer :silence_standard_logging
     attr_accessor :metadata
+    attr_accessor :prefix
 
     def append_fields(&block)
       @append_fields_callback = block
@@ -57,7 +58,7 @@ def log_as_json(payload, as_logstash_event: false)
                        payload.to_json
                      end
 
-      logger << json_payload + $INPUT_RECORD_SEPARATOR
+      logger << (prefix.nil? ? "" : prefix) + json_payload + $INPUT_RECORD_SEPARATOR
     end
 
     def logger
diff --git a/lib/logstasher/railtie.rb b/lib/logstasher/railtie.rb
index de48d86..1489018 100644
--- a/lib/logstasher/railtie.rb
+++ b/lib/logstasher/railtie.rb
@@ -10,6 +10,7 @@ class Railtie < ::Rails::Railtie
     config.logstasher.log_level = ::Logger::INFO
 
     config.logstasher.metadata  = {}
+    config.logstasher.prefix    = ""
     config.before_initialize do
       options = config.logstasher
 
@@ -20,6 +21,7 @@ class Railtie < ::Rails::Railtie
       ::LogStasher.logger                   = options.logger || default_logger
       ::LogStasher.logger.level             = options.log_level
       ::LogStasher.metadata                 = options.metadata
+      ::LogStasher.prefix                   = options.prefix
     end
 
     initializer 'logstasher.load' do
diff --git a/spec/lib/logstasher/logstasher_spec.rb b/spec/lib/logstasher/logstasher_spec.rb
index fb6dfff..1dbdb7e 100644
--- a/spec/lib/logstasher/logstasher_spec.rb
+++ b/spec/lib/logstasher/logstasher_spec.rb
@@ -24,6 +24,19 @@
       end
     end
 
+    context "with prefix" do
+      before { ::LogStasher.prefix = "LOGSTASHER " }
+      after  { ::LogStasher.prefix = nil           }
+
+      it "appends a prefix to log lines." do
+        expect(::LogStasher.logger).to receive(:<<) do |line|
+          expect(line).to match(/^LOGSTASHER /)
+        end
+
+        ::LogStasher.log_as_json(:yolo => :brolo)
+      end
+    end
+
     context "with metadata" do
       before { ::LogStasher.metadata = { :namespace => :cooldude } }
       after { ::LogStasher.metadata = {} }