Disable keep-alive connections.

If there are a sufficient # of connections opened/file descriptors exceeded, Camo will start returning back 404
because of the saturated number of connections.

README.md

@@ -51,6 +51,7 @@ Camo is configured through environment variables.
 * `CAMO_SOCKET_TIMEOUT`: The maximum number of seconds Camo will wait before giving up on fetching an image. (default: 10)
 * `CAMO_TIMING_ALLOW_ORIGIN`: The string for Camo to include in the [`Timing-Allow-Origin` header](http://www.w3.org/TR/resource-timing/#cross-origin-resources) it sends in responses to clients. The header is omitted if this environment variable is not set. (default: not set)
 * `CAMO_HOSTNAME`: The `Camo-Host` header value that Camo will send. (default: `unknown`)
+* `CAMO_KEEP_ALIVE`: Whether or not to enable keep-alive session. (default: `false`)
 
 ## Testing Functionality
 

server.coffee

@@ -14,6 +14,8 @@ max_redirects   = process.env.CAMO_MAX_REDIRECTS   || 4
 camo_hostname   = process.env.CAMO_HOSTNAME        || "unknown"
 socket_timeout  = process.env.CAMO_SOCKET_TIMEOUT  || 10
 logging_enabled = process.env.CAMO_LOGGING_ENABLED || "disabled"
+keep_alive = process.env.CAMO_KEEP_ALIVE || "false"
+
 content_length_limit = parseInt(process.env.CAMO_LENGTH_LIMIT || 5242880, 10)
 
 accepted_image_mime_types = JSON.parse(Fs.readFileSync(
@@ -83,6 +85,9 @@ process_url = (url, transferredHeaders, resp, remaining_redirects) ->
       path: queryPath
       headers: transferredHeaders
 
+    if keep_alive == "false"
+      requestOptions['agent'] = false
+
     srcReq = Protocol.get requestOptions, (srcResp) ->
       is_finished = true