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nrepl_proxy.clj
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nrepl_proxy.clj
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(ns ivarref.nrepl-proxy
(:require [aleph.tcp :as tcp]
[manifold.stream :as stream]
[clojure.tools.logging :as log]
[clj-http.client :as client]
[clojure.string :as str]
[clojure.pprint :as pprint]
[aleph.netty :as netty])
(:import (java.net InetSocketAddress SocketException ConnectException SocketException)
(java.util Base64)
(org.apache.http NoHttpResponseException)))
(defn bytes->base64-str [bytes]
(.encodeToString (Base64/getEncoder) bytes))
(defonce session->stream (atom {}))
(defn opts->extra-headers [{:keys [secret-header secret-value secret-file secret-prefix]}]
{secret-header (str secret-prefix
(or secret-value
(str/trim (slurp secret-file))))})
(defn close-handler [{:keys [endpoint] :as opts} s info open? session-id]
(when-not (stream/closed? s)
(log/info "connection closed"))
(reset! open? false)
(try
(client/post endpoint
{:form-params {:op "close"
:session-id session-id}
:headers (opts->extra-headers opts)
:as :json
:throw-exceptions false
:content-type :json})
(catch Throwable t
(log/debug t "failed to close remote")))
(try
(.close s)
(catch Throwable t
(log/debug t "failed to close local connection"))))
(defn gateway-error? [t]
(when t
(when-let [status (some->> (ex-data t) :status)]
(when (contains? #{502 504} status)
status))))
(defn consume-handler [{:keys [endpoint] :as opts} s info session-id arg]
(log/debug "consume" arg)
(try
(client/post endpoint
{:form-params {:op "send"
:session-id session-id
:payload (bytes->base64-str arg)}
:headers (opts->extra-headers opts)
:as :json
:content-type :json})
(catch Throwable t
(if-let [err (gateway-error? t)]
(do (log/warn "got gateway error code" err "on send")
nil)
(throw t)))))
(defn poll [{:keys [endpoint
give-up-seconds
warn-after-seconds]
:as opts}
s
info
open?
session-id
start-poll-time]
(try
(let [payload (->> (client/post endpoint
{:form-params {:op "recv"
:session-id session-id}
:headers (opts->extra-headers opts)
:as :json
:content-type :json})
:body
:payload)]
(when (not-empty payload)
(log/debug "got data..")
(doseq [line (str/split-lines payload)]
(stream/put! s (.decode (Base64/getDecoder) ^String line)))))
(catch Throwable e
(cond (false? @open?)
(do (log/debug "expected close"))
(= 404 (some->> e (ex-data) :status))
(do
(log/error "session is gone, aborting!")
(reset! open? false)
::session-gone)
(or (instance? ConnectException e)
(instance? NoHttpResponseException e)
(instance? SocketException e)
(gateway-error? e))
(let [ms-since-error (- (System/currentTimeMillis) start-poll-time)]
(cond
(>= ms-since-error (* 1000 give-up-seconds))
(do (log/error "server seems to be down, giving up...!")
(reset! open? false)
::abort)
(>= ms-since-error (* 1000 warn-after-seconds))
(log/warn "server is down for" (int (/ ms-since-error 1000)) "seconds"))
(Thread/sleep 1000)
(poll opts s info open? session-id start-poll-time))
:else
(throw e)))))
(defn handler [{:keys [endpoint poll-delay] :as opts} s info]
(log/info "starting new connection ...")
(let [headers (opts->extra-headers opts)
resp (client/post endpoint
{:form-params {:op "init"}
:headers headers
:as :json
:content-type :json
:throw-exceptions false})]
(if-not (= 200 (:status resp))
(do (log/error "got http status code" (:status resp) "when trying to establish connection")
(log/error "body was:\n" (:body resp))
(log/error "request headers were:\n" (with-out-str (pprint/pprint headers)))
(stream/close! s))
(let [session-id (->> resp
:body
:session-id)
open? (atom true)]
(log/info "new connection established")
(swap! session->stream assoc session-id s)
(stream/on-closed s (fn [& _] (close-handler opts s info open? session-id)))
(stream/consume (fn [arg] (consume-handler opts s info session-id arg)) s)
(future
(while @open?
(try
(poll opts s info open? session-id (System/currentTimeMillis))
(Thread/sleep poll-delay)
(catch Throwable t
(log/warn "error while polling:" (.getMessage t))
;(def tt t)
(Thread/sleep 500))))
(close-handler opts s info open? session-id)
(log/debug "poller exiting" session-id))))))
(defn start-server
[{:keys [bind
port
endpoint
secret-header
secret-file
secret-value
secret-prefix
block?
give-up-seconds
warn-after-seconds
port-file
poll-delay]
:or {bind "127.0.0.1"
port 0
secret-header "authorization"
secret-file ".secret"
secret-value nil
secret-prefix ""
block? true
give-up-seconds 60
warn-after-seconds 5
port-file ".nrepl-proxy-port"
poll-delay 100}
:as opts}]
(let [opts (assoc opts
:bind bind
:port port
:secret-header secret-header
:secret-file secret-file
:secret-value secret-value
:secret-prefix secret-prefix
:give-up-seconds give-up-seconds
:warn-after-seconds warn-after-seconds
:port-file port-file
:poll-delay poll-delay)]
(assert (string? endpoint) "must be given :endpoint!")
(let [server (tcp/start-server (fn [s info] (handler opts s info)) {:socket-address (InetSocketAddress. ^String bind ^Integer port)})]
(log/info "started proxy server on" (str bind "@" (netty/port server)))
(log/info "using remote endpoint" endpoint)
(spit port-file (netty/port server))
(log/info "wrote port" (netty/port server) "to" port-file)
(.addShutdownHook
(Runtime/getRuntime)
(Thread.
^Runnable (fn []
(try
(log/info "shutting down server")
(.close server)
(catch Throwable t
(log/warn t "error during closing server"))))))
(when block?
@(promise)))))
(comment
(start-server
{:endpoint (str/trim (slurp ".nrepl-url"))
:secret-header "nrepl-token"
:secret-file ".nrepl-token"
:give-up-seconds 10
:block? false}))