update readme to recent enhancements

README.md

@@ -1,9 +1,9 @@
 A syslog daemon implementing circular buffer, in-memory storage.
 
-This is useful when you want to keep some (heavy detailed) log available, but you don't want to log too many
+This is useful when you want to keep some (heavily detailed) log available, but you don't want to log too many
-things to disk.
+things to disk. Remember: logging is useful, but can be dangerous to your users' privacy!
 
-On your "main" syslog, send some message to this one!
+On your "main" syslog, forward (part of the) messages to this one!
 
 ## Integration examples
 
@@ -27,15 +27,59 @@ and run `circologd -syslogd-socket /run/circolog-syslog.sock -query-socket /run/
 
 ## Client
 
-`curl` might be enough of a client for most uses.
+`circolog` has its own client: `circolog-tail`. It is intended to resemble `tail -f` for the most basic
+options; however, it will include filtering options that are common when you want to read logs, because that's
+very easy when you have structured logs available.
+
+However, one design point of circolog is to be usable without having a specific client: so the logs are
+offered on both HTTP and websocket. This means that you can use `curl` if you want:
 
     curl --unix-socket /run/circolog-query.sock localhost/
 
-will give you everything that circologd has in memory
+will give you everything that circologd has in memory.
 
 If you want to "follow" (as in `tail -f`) you need to use the websocket interface. However, I don't know of
 any websocket client supporting UNIX domain socket, so you have two options:
 
- 1. wait until I write a proper `circolog-tail` client implementing it all
+ 1. Use `circolog-tail`
  2. Use `circologd` with `-query-addr 127.0.0.1:9080`, add some iptables rule to prevent non-root to access that
     port, and run `ws ws://localhost:9080/ws`. You'll get all the "backlog", and will follow new log messages.
+
+### HTTP URLs and parameters
+
+When using HTTP, logs are served on `/`. Valid parameters are:
+
+ * `l`. This is the amount of lines to send. This is essentially the same as the `-n` parameter on tail
+    Using `l=-1` (the default) means "give me every log message that you have
+ * `fmt`. This selects the output format. When `fmt=json` is used, each message is returned as JSON structured
+     data. The format of those JSON messages is still unstable. `fmt=syslog`, the default, outputs messages using "syslog style" (RFC XXXXXX)
+
+To use websocket, request path `/ws`. The same parameters of `/` are recognized.
+
+## Control daemon
+
+Circologd can be controlled, on some aspects, at run-time. It has 2 mechanisms for that: the easiest, and more
+limited, is sending a signal with kill; the second, and more powerful, is a control socket, where you can give
+commands to it. This control socket is just HTTP, so again `curl` is your friend. In the future a
+`circolog-ctl` client will be developed.
+
+### Pause
+
+When circologd is paused, every new message it receives is immediately discarded. No exception. The backlog
+is, however, preserved. This means that you can trigger the event that you want to investigate, pause
+circolog, then analyze the logs.
+Pausing might be the easiest way to make circologd only run "when needed".
+
+When circologd resumes, no previous message is lost.
+
+
+To pause circologd with signals , send a `USR1` signal to the main pid. To "resume", send a `USR1` again.
+
+To pause with HTTP, send a `POST /pause/toggle` to your circologd control socket.
+
+### Clear
+
+When you clear the circologd's buffer, it will discard every message it has, but will keep collecting new
+messages.
+
+You can do that with `POST /logs/clear`

cmd/circologd/main.go

@@ -32,7 +32,7 @@ func main() {
 	flag.Parse()
 
 	interrupt := make(chan os.Signal, 1)
-	signal.Notify(interrupt, syscall.SIGINT, syscall.SIGHUP, syscall.SIGUSR1, syscall.SIGTERM)
+	signal.Notify(interrupt, syscall.SIGINT, syscall.SIGUSR1, syscall.SIGTERM)
 
 	hub := circolog.NewHub(*bufsize)
 	handler := syslog.NewChannelHandler(hub.LogMessages)
@@ -106,11 +106,6 @@ func main() {
 	for {
 		select {
 		case sig := <-interrupt:
-			if sig == syscall.SIGHUP {
-				hub.Commands <- circolog.HubFullCommand{Command: circolog.CommandClear}
-				<-hub.Responses
-				log.Println("Queue cleared")
-			}
 			if sig == syscall.SIGUSR1 {
 				hub.Commands <- circolog.HubFullCommand{Command: circolog.CommandPauseToggle}
 				resp := <-hub.Responses