[#41] socket REPL

.gitignore

@@ -12,3 +12,4 @@ pom.xml.asc
 .hg/
 /bb
 .clj-kondo/.cache
+!java/src/babashka/impl/LockFix.class

README.md

@@ -249,6 +249,32 @@ export BABASHKA_PRELOADS='(load-file "my_awesome_prelude.clj")'
 
 Note that `*in*` is not available in preloads.
 
+## Socket REPL
+
+Start the socket REPL like this:
+
+``` shellsession
+$ bb --socket-repl 1666
+Babashka socket REPL started at localhost:1666
+```
+
+Now you can connect with your favorite socket REPL client:
+
+``` shellsession
+$ rlwrap nc 127.0.0.1 1666
+Babashka v0.0.14-SNAPSHOT REPL.
+Use :repl/quit or :repl/exit to quit the REPL.
+Clojure rocks, Bash reaches.
+
+bb=> (+ 1 2 3)
+6
+bb=> :repl/quit
+$
+```
+
+A socket REPL client for Emacs is
+[inf-clojure](https://github.com/clojure-emacs/inf-clojure).
+
 ## Enabling SSL
 
 If you want to be able to use SSL to e.g. run `(slurp
@@ -360,4 +386,5 @@ beverage](https://ko-fi.com/borkdude).
 
 Copyright © 2019 Michiel Borkent
 
-Distributed under the EPL License, same as Clojure. See LICENSE.
+Distributed under the EPL License. This project contains modified Clojure code
+which is licensed under the same EPL License. See LICENSE.

project.clj

@@ -9,10 +9,8 @@
             :url "http://opensource.org/licenses/eclipse-1.0.php"}
   :source-paths ["src" "sci/src" "sci/inlined"]
   :resource-paths ["resources" "sci/resources"]
-  :dependencies [[org.clojure/clojure "1.9.0"]]
-  :profiles {:clojure-1.9.0 {:dependencies [[org.clojure/clojure "1.9.0"]]}
-             :clojure-1.10.1 {:dependencies [[org.clojure/clojure "1.10.1"]]}
-             :test {:dependencies [[clj-commons/conch "0.9.2"]]}
+  :dependencies [[org.clojure/clojure "1.10.1"]]
+  :profiles {:test {:dependencies [[clj-commons/conch "0.9.2"]]}
              :uberjar {:global-vars {*assert* false}
                        :jvm-opts ["-Dclojure.compiler.direct-linking=true"
                                   "-Dclojure.spec.skip-macros=true"]

script/compile

@@ -23,7 +23,7 @@ BABASHKA_VERSION=$(cat resources/BABASHKA_VERSION)
 # mkdir -p src/sci
 # cp -R /tmp/sci/src/* src
 
-lein with-profiles +clojure-1.10.1 do clean, uberjar
+lein do clean, uberjar
 $NATIVE_IMAGE \
   -jar target/babashka-$BABASHKA_VERSION-standalone.jar \
   -H:Name=bb \

script/test

@@ -3,12 +3,4 @@
 set -eo pipefail
 export BABASHKA_PRELOADS='(defn __bb__foo [] "foo") (defn __bb__bar [] "bar")'
 
-if [ "$BABASHKA_TEST_ENV" = "native" ]; then
 lein test
-else
-    echo "Testing with Clojure 1.9.0"
-    lein with-profiles +clojure-1.9.0 test
-
-    echo "Testing with Clojure 1.10.1"
-    lein with-profiles +clojure-1.10.1 test
-fi

src/babashka/impl/clojure/core/server.clj

@@ -0,0 +1,100 @@
+;;  Modified / stripped version of clojure.core.server for use with babashka on
+;;  GraalVM.
+;;
+;;   Copyright (c) Rich Hickey. All rights reserved.
+;;   The use and distribution terms for this software are covered by the
+;;   Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)
+;;   which can be found in the file epl-v10.html at the root of this distribution.
+;;   By using this software in any fashion, you are agreeing to be bound by
+;;   the terms of this license.
+;;   You must not remove this notice, or any other, from this software.
+
+(ns ^{:doc "Socket server support"
+      :author "Alex Miller"
+      :no-doc true}
+    babashka.impl.clojure.core.server
+  (:refer-clojure :exclude [locking])
+  (:import
+   [clojure.lang LineNumberingPushbackReader]
+   [java.net InetAddress Socket ServerSocket SocketException]
+   [java.io Reader Writer PrintWriter BufferedWriter BufferedReader InputStreamReader OutputStreamWriter]))
+
+(set! *warn-on-reflection* true)
+
+(def server (atom nil))
+
+(defmacro ^:private thread
+  [^String name daemon & body]
+  `(doto (Thread. (fn [] ~@body) ~name)
+     (.setDaemon ~daemon)
+     (.start)))
+
+(defn- accept-connection
+  "Start accept function, to be invoked on a client thread, given:
+    conn - client socket
+    name - server name
+    client-id - client identifier
+    in - in stream
+    out - out stream
+    err - err stream
+    accept - accept fn symbol to invoke
+    args - to pass to accept-fn"
+  [^Socket conn client-id in out err accept args]
+  (try
+    (binding [*in* in
+              *out* out
+              *err* err]
+      (swap! server assoc-in [:sessions client-id] {})
+      (apply accept args))
+    (catch SocketException _disconnect)
+    (finally
+      (swap! server update-in [:sessions] dissoc client-id)
+      (.close conn))))
+
+(defn start-server
+  "Start a socket server given the specified opts:
+    :address Host or address, string, defaults to loopback address
+    :port Port, integer, required
+    :name Name, required
+    :accept Namespaced symbol of the accept function to invoke, required
+    :args Vector of args to pass to accept function
+    :bind-err Bind *err* to socket out stream?, defaults to true
+    :server-daemon Is server thread a daemon?, defaults to true
+    :client-daemon Are client threads daemons?, defaults to true
+   Returns server socket."
+  [opts]
+  (let [{:keys [address port name accept args bind-err server-daemon client-daemon]
+         :or {bind-err true
+              server-daemon true
+              client-daemon true}} opts
+        address (InetAddress/getByName address)  ;; nil returns loopback
+        socket (ServerSocket. port 0 address)]
+    (reset! server {:name name, :socket socket, :sessions {}})
+    (thread
+      (str "Clojure Server " name) server-daemon
+      (try
+        (loop [client-counter 1]
+          (when (not (.isClosed socket))
+            (try
+              (let [conn (.accept socket)
+                    in (LineNumberingPushbackReader. (InputStreamReader. (.getInputStream conn)))
+                    out (BufferedWriter. (OutputStreamWriter. (.getOutputStream conn)))
+                    client-id (str client-counter)]
+                (thread
+                  (str "Clojure Connection " name " " client-id) client-daemon
+                  (accept-connection conn client-id in out (if bind-err out *err*) accept args)))
+              (catch SocketException _disconnect))
+            (recur (inc client-counter))))
+        (finally
+          (reset! server nil))))
+    socket))
+
+(defn stop-server
+  "Stop server with name or use the server-name from *session* if none supplied.
+  Returns true if server stopped successfully, nil if not found, or throws if
+  there is an error closing the socket."
+  []
+  (when-let [s @server]
+    (when-let [server-socket ^ServerSocket (get s :socket)]
+      (.close server-socket)))
+  (reset! server nil))

src/babashka/impl/clojure/main.clj

@@ -0,0 +1,143 @@
+;;  Modified / stripped version of clojure.main for use with babashka on
+;;  GraalVM.
+;;
+;; Copyright (c) Rich Hickey All rights reserved. The use and
+;; distribution terms for this software are covered by the Eclipse Public
+;; License 1.0 (http://opensource.org/licenses/eclipse-1.0.php) which can be found
+;; in the file epl-v10.html at the root of this distribution. By using this
+;; software in any fashion, you are agreeing to be bound by the terms of
+;; this license. You must not remove this notice, or any other, from this
+;; software.
+
+;; Originally contributed by Stephen C. Gilardi
+
+(ns ^{:doc "Top-level main function for Clojure REPL and scripts."
+      :author "Stephen C. Gilardi and Rich Hickey"
+      :no-doc true}
+    babashka.impl.clojure.main
+  (:refer-clojure :exclude [with-bindings])
+  (:import (java.io StringReader)
+           (clojure.lang LineNumberingPushbackReader LispReader$ReaderException)))
+
+(defmacro with-bindings
+  "Executes body in the context of thread-local bindings for several vars
+  that often need to be set!: *ns* *warn-on-reflection* *math-context*
+  *print-meta* *print-length* *print-level* *compile-path*
+  *command-line-args* *1 *2 *3 *e"
+  [& body]
+  `(binding [*ns* *ns*
+             *warn-on-reflection* *warn-on-reflection*
+             *math-context* *math-context*
+             *print-meta* *print-meta*
+             *print-length* *print-length*
+             *print-level* *print-level*
+             *print-namespace-maps* true
+             *data-readers* *data-readers*
+             *default-data-reader-fn* *default-data-reader-fn*
+             *command-line-args* *command-line-args*
+             *unchecked-math* *unchecked-math*
+             *assert* *assert*
+             ;; clojure.spec.alpha/*explain-out* clojure.spec.alpha/*explain-out*
+             *1 nil
+             *2 nil
+             *3 nil
+             *e nil]
+     ~@body))
+
+(defn repl-prompt
+  "Default :prompt hook for repl"
+  []
+  (print "bb=> " ))
+
+(defn repl-caught
+  "Default :caught hook for repl"
+  [e]
+  (binding [*out* *err*]
+    (println (.getMessage ^Exception e))
+    (flush)))
+
+(defn repl
+  "Generic, reusable, read-eval-print loop. By default, reads from *in*,
+  writes to *out*, and prints exception summaries to *err*. If you use the
+  default :read hook, *in* must either be an instance of
+  LineNumberingPushbackReader or duplicate its behavior of both supporting
+  .unread and collapsing CR, LF, and CRLF into a single \\newline. Options
+  are sequential keyword-value pairs. Available options and their defaults:
+     - :init, function of no arguments, initialization hook called with
+       bindings for set!-able vars in place.
+       default: #()
+     - :need-prompt, function of no arguments, called before each
+       read-eval-print except the first, the user will be prompted if it
+       returns true.
+       default: (if (instance? LineNumberingPushbackReader *in*)
+                  #(.atLineStart *in*)
+                  #(identity true))
+     - :prompt, function of no arguments, prompts for more input.
+       default: repl-prompt
+     - :flush, function of no arguments, flushes output
+       default: flush
+     - :read, function of two arguments, reads from *in*:
+         - returns its first argument to request a fresh prompt
+           - depending on need-prompt, this may cause the repl to prompt
+             before reading again
+         - returns its second argument to request an exit from the repl
+         - else returns the next object read from the input stream
+       default: repl-read
+     - :eval, function of one argument, returns the evaluation of its
+       argument
+       default: eval
+     - :print, function of one argument, prints its argument to the output
+       default: prn
+     - :caught, function of one argument, a throwable, called when
+       read, eval, or print throws an exception or error
+       default: repl-caught"
+  [& options]
+  (let [{:keys [init need-prompt prompt flush read eval print caught]
+         :or {need-prompt (if (instance? LineNumberingPushbackReader *in*)
+                            #(.atLineStart ^LineNumberingPushbackReader *in*)
+                            #(identity true))
+              prompt      repl-prompt
+              flush       flush
+              print       prn
+              caught      repl-caught}}
+        (apply hash-map options)
+        request-prompt (Object.)
+        request-exit (Object.)
+        read-eval-print
+        (fn []
+          (try
+            (let [input (try
+                          (read request-prompt request-exit)
+                          (catch LispReader$ReaderException e
+                            (throw (ex-info nil {:clojure.error/phase :read-source} e))))]
+              (or (#{request-prompt request-exit} input)
+                  (let [value (eval input)]
+                    (set! *3 *2)
+                    (set! *2 *1)
+                    (set! *1 value)
+                    (try
+                      (print value)
+                      (catch Throwable e
+                        (throw (ex-info nil {:clojure.error/phase :print-eval-result} e)))))))
+            (catch Throwable e
+              (caught e)
+              (set! *e e))))]
+    (with-bindings
+      (try
+        (init)
+        (catch Throwable e
+          (caught e)
+          (set! *e e)))
+      (prompt)
+      (flush)
+      (loop []
+        (when-not
+            (try (identical? (read-eval-print) request-exit)
+                 (catch Throwable e
+                   (caught e)
+                   (set! *e e)
+                   nil))
+          (when (need-prompt)
+            (prompt)
+            (flush))
+          (recur))))))

src/babashka/impl/socket_repl.clj

@@ -0,0 +1,66 @@
+(ns babashka.impl.socket-repl
+  {:no-doc true}
+  (:require [babashka.impl.clojure.core.server :as server]
+            [babashka.impl.clojure.main :as m]
+            [sci.core :refer [eval-string]]
+            [sci.impl.parser :as parser]
+            [sci.impl.toolsreader.v1v3v2.clojure.tools.reader.reader-types :as r]
+            [clojure.string :as str]
+            [clojure.java.io :as io]))
+
+(set! *warn-on-reflection* true)
+
+(defn repl
+  "REPL with predefined hooks for attachable socket server."
+  [sci-opts]
+  (m/repl
+   :init #(do (println "Babashka"
+                       (str "v" (str/trim (slurp (io/resource "BABASHKA_VERSION"))))
+                       "REPL.")
+              (println "Use :repl/quit or :repl/exit to quit the REPL.")
+              (println "Clojure rocks, Bash reaches.")
+              (println))
+   :read (fn [request-prompt request-exit]
+           (let [in (r/indexing-push-back-reader (r/push-back-reader *in*))
+                 p (r/peek-char in)]
+             (if (= \newline p)
+               (do (r/read-char in) request-prompt)
+               (let [v (parser/parse-next {} in)]
+                 (if (or (identical? :repl/quit v)
+                         (identical? :repl/exit v))
+                   request-exit
+                   v)))))
+   :eval (fn [expr]
+           (eval-string (str expr)
+                        (update sci-opts
+                                :bindings
+                                merge {'*1 *1
+                                       '*2 *2
+                                       '*3 *3
+                                       '*e *e})))))
+
+(defn start-repl! [host+port sci-opts]
+  (let [parts (str/split host+port #":")
+        [host port] (if (= 1 (count parts))
+                      [nil (Integer. ^String (first parts))]
+                      [(first parts) (Integer. ^String (second parts))])
+        host+port (if-not host (str "localhost:" port)
+                          host+port)
+        socket (server/start-server
+                {:address host
+                 :port port
+                 :name "bb"
+                 :accept babashka.impl.socket-repl/repl
+                 :args [sci-opts]})]
+    (println "Babashka socket REPL started at" host+port)
+    socket))
+
+(defn stop-repl! []
+  (server/stop-server))
+
+(comment
+  (def sock (start-repl! "0.0.0.0:1666" {:env (atom {})}))
+  (.accept sock)
+  @#'server/servers
+  (stop-repl!)
+  )

src/babashka/main.clj

@@ -7,6 +7,7 @@
    [clojure.java.io :as io]
    [clojure.java.shell :as shell]
    [clojure.string :as str]
+   [babashka.impl.socket-repl :as socket-repl]
    [sci.core :as sci])
   (:import [sun.misc Signal]
            [sun.misc SignalHandler])
@@ -55,6 +56,11 @@
                      (recur (rest options)
                             (assoc opts-map
                                    :file (first options))))
+                   ("--socket-repl")
+                   (let [options (rest options)]
+                     (recur (rest options)
+                            (assoc opts-map
+                                   :socket-repl (first options))))
                    (if (not (:file opts-map))
                      (assoc opts-map
                             :expression opt
@@ -80,7 +86,7 @@
 (defn print-version []
   (println (str "babashka v"(str/trim (slurp (io/resource "BABASHKA_VERSION"))))))
 
-(def usage-string "Usage: bb [ --help ] | [ --version ] | [ -i | -I ] [ -o | -O ] [ --stream ] ( expression | -f <file> )")
+(def usage-string "Usage: bb [ --help ] | [ --version ] | [ -i | -I ] [ -o | -O ] [ --stream ] ( expression | -f <file> | --socket-repl [host:]port )")
 (defn print-usage []
   (println usage-string))
 
@@ -101,6 +107,7 @@
   -O: write EDN values to stdout.
   --stream: stream over lines or EDN values from stdin. Combined with -i or -I *in* becomes a single value per iteration.
   --file or -f: read expressions from file instead of argument wrapped in an implicit do.
+  --socket-repl: start socket REPL. Specify port (e.g. 1666) or host and port separated by colon (e.g. 127.0.0.1:1666).
   --time: print execution time before exiting.
 "))
 
@@ -178,7 +185,7 @@
   (let [t0 (System/currentTimeMillis)
         {:keys [:version :shell-in :edn-in :shell-out :edn-out
                 :help? :file :command-line-args
-                :expression :stream? :time?] :as _opts}
+                :expression :stream? :time? :socket-repl] :as _opts}
         (parse-opts args)
         read-next #(if (pipe-signal-received?)
                      ::EOF
@@ -205,12 +212,15 @@
                 [(print-version) 0]
                 help?
                 [(print-help) 0]
+                socket-repl [(do (socket-repl/start-repl! socket-repl ctx)
+                                 @(promise)) 0]
                 :else
                 (try
                   (let [expr (if file (read-file file) expression)]
                     (loop [in (read-next)]
                       (let [ctx (update ctx :bindings assoc (with-meta '*in*
-                                                              (when-not stream? {:sci/deref! true})) in)]
+                                                              (when-not stream?
+                                                                {:sci/deref! true})) in)]
                         (if (identical? ::EOF in)
                           [nil 0] ;; done streaming
                           (let [res [(do (when-not (or expression file)

test/babashka/impl/socket_repl_test.clj

@@ -0,0 +1,20 @@
+(ns babashka.impl.socket-repl-test
+  (:require
+   [babashka.impl.socket-repl :refer [start-repl! stop-repl!]]
+   [babashka.test-utils :as tu]
+   [clojure.java.shell :refer [sh]]
+   [clojure.string :as str]
+   [clojure.test :as t :refer [deftest is]]))
+
+(deftest socket-repl-test
+  (when tu/jvm?
+    (start-repl! "0.0.0.0:1666" {:env (atom {})})
+    (is (str/includes? (:out (sh "bash" "-c"
+                                 "echo \"(+ 1 2 3)\n:repl/exit\" | nc 127.0.0.1 1666"))
+                       "bb=> 6"))
+    (stop-repl!)))
+
+;;;; Scratch
+
+(comment
+  )