Update README.md with accurate config

[finishes #137179173]

Signed-off-by: Chris Hendrix <[email protected]>

README.md

@@ -4,18 +4,17 @@
 
 ![Black Box Flight Recorder](http://i.imgur.com/sCSNdzU.jpg)
 
-## about
+## About
 
 Applications often provide only a limited ability to log to syslog and often
 don't log in a consistent format. I also think that syslog is an operational
 concern and the application should not know about where it is logging. Blackbox
 is an experiment to decouple syslogging from an application without messing
 about with syslog configuration (which is tricky on BOSH VMs).
 
-Blackbox will tail specified files and forward any new lines to a syslog
-server.
+Blackbox will tail all files in sub-directories of a specified `source_dir`, and forward any new lines to a syslog server.
 
-## usage
+## Usage
 
 ```
 blackbox -config config.yml
@@ -26,20 +25,31 @@ The configuration file schema is as follows:
 ``` yaml
 hostname: this-host
 
-destination:
-  transport: udp
-  address: logs.example.com:1234
+syslog:
+  destination:
+    transport: udp
+    address: logs.example.com:1234
 
-sources:
-  - path: hello.txt
-    tag: hello
+  source_dir: /path/to/log-dir
 ```
 
-Each file can be sent with a different tag. Currently the priority and facility
-are hardcoded to `INFO` and `user`. However, allowing customisation of these
-per source would not be difficult.
+Consider the case where `log-dir` has the following structure:
 
-## installation
+```
+/path/to/log-dir
+|-- app1
+|   |-- stdout.log
+|   `-- stderr.log
+`-- app2
+    |-- foo.log
+    `-- bar.log
+```
+
+Any new lines written to `app1/stdout.log` and `app1/stderr.log` get sent to syslog tagged as `app1`, while new lines written to `app2/foo.log` and `app2/bar.log` get sent to syslog tagged as `app2`.
+
+Currently the priority and facility are hardcoded to `INFO` and `user`.
+
+## Installation
 
 ```
 go get -u github.com/concourse/blackbox/cmd/blackbox

config.go

@@ -34,11 +34,6 @@ func (d *Duration) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	return nil
 }
 
-type SyslogSource struct {
-	Path string `yaml:"path"`
-	Tag  string `yaml:"tag"`
-}
-
 type SyslogConfig struct {
 	Destination syslog.Drain `yaml:"destination"`
 	SourceDir   string       `yaml:"source_dir"`