Extract Processor#log_context to ease extending what's logged (#3463)

* Extract Processor#log_context to ease extending what's logged

This was previously exposed in JobLogger and Middleware::Server::Logging
but was inlined into Processor.
701e06224c

Useful, e.g. in this case:
https://github.com/mperham/sidekiq/issues/1786

* Move job hash context logic into Sidekiq::Logging

Changes.md

@@ -8,6 +8,7 @@ HEAD
 - Reimplement Web UI's HTTP\_ACCEPT\_LANGUAGE parsing because the spec is utterly
   incomprehensible for various edge cases. [johanlunds, natematykiewicz, #3449]
 - Update `class_attribute` core extension to avoid warnings
+- Expose `job_hash_context` from `Sidekiq::Logging` to support log customization
 
 5.0.0
 -----------

lib/sidekiq/logging.rb

@@ -26,6 +26,18 @@ module Sidekiq
       end
     end
 
+    def self.job_hash_context(job_hash)
+      # If we're using a wrapper class, like ActiveJob, use the "wrapped"
+      # attribute to expose the underlying thing.
+      klass = job_hash['wrapped'.freeze] || job_hash["class".freeze]
+      bid = job_hash['bid'.freeze]
+      "#{klass} JID-#{job_hash['jid'.freeze]}#{" BID-#{bid}" if bid}"
+    end
+
+    def self.with_job_hash_context(job_hash, &block)
+      with_context(job_hash_context(job_hash), &block)
+    end
+
     def self.with_context(msg)
       Thread.current[:sidekiq_context] ||= []
       Thread.current[:sidekiq_context] << msg

lib/sidekiq/processor.rb

@@ -125,12 +125,7 @@ module Sidekiq
       # job structure to the Web UI
       pristine = cloned(job_hash)
 
-      # If we're using a wrapper class, like ActiveJob, use the "wrapped"
-      # attribute to expose the underlying thing.
-      klass = job_hash['wrapped'.freeze] || job_hash["class".freeze]
-      ctx = "#{klass} JID-#{job_hash['jid'.freeze]}#{" BID-#{job_hash['bid'.freeze]}" if job_hash['bid'.freeze]}"
-
-      Sidekiq::Logging.with_context(ctx) do
+      Sidekiq::Logging.with_job_hash_context(job_hash) do
         @retrier.global(job_hash, queue) do
           @logging.call(job_hash, queue) do
             stats(pristine, queue) do