Introduce property to log filename with blackbox

This release now includes the property `syslog.blackbox.log_filename`.
It is passed to blackbox. If set to true, blackbox tags its log lines with the filename.
Therefore, the syslog `app-name` field will also hold the log filename.

Also blackbox is bumped to support the log_filename property.

[#159100361](https://www.pivotaltracker.com/story/show/159100361)

Co-authored-by: Max Becker <[email protected]>

Author: FlorianNachtigall

jobs/syslog_forwarder/spec

@@ -133,6 +133,10 @@ properties:
       log lines will be tagged with subdirectory name.
     default: /var/vcap/sys/log
 
+  syslog.blackbox.log_filename:
+    description: If set to true, log lines are also tagged with filename in the format <subdirectory>/<file.log>.
+    default: false
+
   syslog.blackbox.limit_cpu:
     description: limit goprocess to a single cpu via gomaxprocs
     default: true

jobs/syslog_forwarder/templates/blackbox_config.yml.erb

@@ -10,3 +10,4 @@ syslog:
     address: 127.0.0.1:514
 
   source_dir: <%= p("syslog.blackbox.source_dir") %>
+  log_filename: <%= p("syslog.blackbox.log_filename") %>