feat: support nginx unix sockets #2

this adventure started two years ago when we hit a roadblock because
crystal didn't support entirely and was about to drop support for dgram
sockets, which is the only unix socket nginx supports.

src/access_log.cr

@@ -1,4 +1,5 @@
 require "json"
+require "socket"
 require "sqlite3"
 require "pg"
 require "option_parser"
@@ -8,6 +9,8 @@ require "./models/crawler"
 
 VERSION = "0.3.0"
 
+# Default socket location
+socket = "/tmp/access_log.socket"
 # The default database URI
 database = "sqlite3://./development.sqlite3"
 # Detect web crawlers
@@ -65,6 +68,9 @@ if crawler
   crawler_re = Regex.union(crawlers.map { |c| c.pattern })
 end
 
+server = Socket.unix(Socket::Type::DGRAM)
+server.bind Socket::UNIXAddress.new(socket)
+
 # Just exit
 Signal::INT.trap do
   exit
@@ -77,8 +83,11 @@ end
 
 # Open the database and wait for JSONL input.
 db = DB.open database do |db|
-  while (json = gets)
+  while true
     begin
+      msg, _ = server.receive(1024 * 64) # 64K
+      _, _, _, _, json = msg.split(" ", 5)
+
       # Parse input
       access_log = AccessLog.from_json(json || "{}")