From f116a6d298262483b7321e1e2adb6873b5a93ae2 Mon Sep 17 00:00:00 2001
From: Francesco Belladonna <francesco@fc5.me>
Date: Mon, 18 Aug 2025 13:47:39 -0700
Subject: [PATCH] Add high priority fields to beginning of JSON object when
 json format

---
 CHANGELOG.md                          |  2 ++
 lib/semantic_logger/formatters/raw.rb |  6 ++--
 test/formatters/json_test.rb          | 45 +++++++++++++++++++++++++++
 3 files changed, 50 insertions(+), 3 deletions(-)
 create mode 100644 test/formatters/json_test.rb

diff --git a/CHANGELOG.md b/CHANGELOG.md
index fc9a74d4..fe2fc31b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,8 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [unreleased]
 
+- Add high priority fields (timestamp, level, level index and message) to beginning of JSON object output when using JSON formatter to ensure log entries are parsable even when JSON logs are mangled
+
 ## [4.17.0]
 
 - Correct `source_code_uri` URL
diff --git a/lib/semantic_logger/formatters/raw.rb b/lib/semantic_logger/formatters/raw.rb
index 44fffa9f..d82b1bc7 100644
--- a/lib/semantic_logger/formatters/raw.rb
+++ b/lib/semantic_logger/formatters/raw.rb
@@ -117,11 +117,12 @@ def call(log, logger)
         self.log    = log
         self.logger = logger
 
+        time
+        level
+        message
         host
         application
         environment
-        time
-        level
         pid
         thread_name
         file_name_and_line
@@ -129,7 +130,6 @@ def call(log, logger)
         tags
         named_tags
         name
-        message
         payload
         exception
         metric
diff --git a/test/formatters/json_test.rb b/test/formatters/json_test.rb
new file mode 100644
index 00000000..d1569190
--- /dev/null
+++ b/test/formatters/json_test.rb
@@ -0,0 +1,45 @@
+require_relative "../test_helper"
+
+module SemanticLogger
+  module Formatters
+    class JsonTest < Minitest::Test
+      describe Json do
+        let(:log_time) do
+          Time.utc(2017, 1, 14, 8, 32, 5.375276)
+        end
+
+        let(:level) do
+          :debug
+        end
+
+        let(:log) do
+          log      = SemanticLogger::Log.new("JsonTest", level)
+          log.time = log_time
+          log
+        end
+
+        let(:expected_time) do
+          SemanticLogger::Formatters::Base::PRECISION == 3 ? "2017-01-14T08:32:05.375Z" : "2017-01-14T08:32:05.375276Z"
+        end
+
+        let(:formatter) do
+          formatter = SemanticLogger::Formatters::Json.new(log_host: false)
+          # Does not use the logger instance for formatting purposes
+          formatter.call(log, nil)
+          formatter
+        end
+
+        describe "call" do
+          it "sets timestamp, level, level_index, and message at the beginning of the JSON object" do
+            log.message = "Some message"
+            expected_start = %({"timestamp":"#{expected_time}","level":"debug","level_index":1,"message":"Some message")
+
+            is_starting_with_high_priority_fields = formatter.call(log, nil).start_with?(expected_start)
+
+            assert is_starting_with_high_priority_fields, "Expected #{formatter.call(log, nil)} to start with #{expected_start}"
+          end
+        end
+      end
+    end
+  end
+end