Improve SSHKit backend with Channel.select

example/exec.rb

@@ -1,6 +1,5 @@
 #!/usr/bin/env ruby
 require 'libssh'
-require 'io/wait'
 
 GC.stress = true
 puts "libssh #{LibSSH::LIBSSH_VERSION}"
@@ -43,24 +42,14 @@
 channel.open_session do
   channel.request_exec('ps auxf')
   until channel.eof?
-    io.wait_readable
-
-    loop do
-      out = channel.read_nonblocking(bufsiz)
-      if out && !out.empty?
-        $stdout.write(out)
-      else
-        break
-      end
+    LibSSH::Channel.select([channel], [], [], nil)
+    out = channel.read_nonblocking(bufsiz)
+    if out && !out.empty?
+      $stdout.write(out)
     end
-
-    loop do
-      err = channel.read_nonblocking(bufsiz, true)
-      if err && !err.empty?
-        $stderr.write(err)
-      else
-        break
-      end
+    err = channel.read_nonblocking(bufsiz, stderr: true)
+    if err && !err.empty?
+      $stderr.write(err)
     end
   end
 end

ext/libssh_ruby/channel.c

@@ -588,7 +588,7 @@ static void set_select_channels(ssh_channel **c_channels, VALUE rb_channels) {
  *  @param [Array<Channel>] read_channels
  *  @param [Array<Channel>] write_channels
  *  @param [Array<Channel>] except_channels
- *  @param [Fixnum] timeout timeout in seconds.
+ *  @param [Fixnum, nil] timeout timeout in seconds.
  *  @return [nil]
  *  @see http://api.libssh.org/stable/group__libssh__channel.html
  *    ssh_channel_select

lib/sshkit/backends/libssh.rb

@@ -1,5 +1,4 @@
 require 'libssh'
-require 'io/wait'
 require 'sshkit/backends/abstract'
 require 'sshkit/backends/connection_pool'
 
@@ -53,8 +52,11 @@ def upload!(local, remote, _options = {})
             scp.init do
               scp.push_file(File.basename(remote), io.size, mode)
               info "Uploading #{remote}"
-              while (buf = io.read(BUFSIZ))
-                scp.write(buf)
+              begin
+                loop do
+                  scp.write(io.readpartial(BUFSIZ))
+                end
+              rescue EOFError
               end
             end
           end
@@ -110,33 +112,24 @@ def execute_command(cmd)
 
         with_session do |session|
           channel = LibSSH::Channel.new(session)
-          io = IO.for_fd(session.fd, autoclose: false)
           channel.open_session do
             if Libssh.config.pty
               channel.request_pty
             end
             channel.request_exec(cmd.to_command)
             until channel.eof?
-              io.wait_readable
-
-              loop do
-                buf = channel.read_nonblocking(BUFSIZ)
-                if buf && !buf.empty?
-                  cmd.on_stdout(channel, buf)
-                  output.log_command_data(cmd, :stdout, buf)
-                else
-                  break
-                end
+              LibSSH::Channel.select([channel], [], [], nil)
+
+              buf = channel.read_nonblocking(BUFSIZ)
+              if buf && !buf.empty?
+                cmd.on_stdout(channel, buf)
+                output.log_command_data(cmd, :stdout, buf)
               end
 
-              loop do
-                buf = channel.read_nonblocking(BUFSIZ, true)
-                if buf && !buf.empty?
-                  cmd.on_stderr(channel, buf)
-                  output.log_command_data(cmd, :stderr, buf)
-                else
-                  break
-                end
+              buf = channel.read_nonblocking(BUFSIZ, stderr: true)
+              if buf && !buf.empty?
+                cmd.on_stderr(channel, buf)
+                output.log_command_data(cmd, :stderr, buf)
               end
             end