Add a gitlab:tcp_check rake task

This allows us to avoid relying on telnet / netcat being installed

1 files changed, 45 insertions, 0 deletions

diff --git a/lib/gitlab/tcp_checker.rb b/lib/gitlab/tcp_checker.rb
new file mode 100644
index 00000000000..6e24e46d0ea
--- /dev/null
+++ b/lib/gitlab/tcp_checker.rb
@@ -0,0 +1,45 @@
+module Gitlab
+  class TcpChecker
+    attr_reader :remote_host, :remote_port, :local_host, :local_port, :error
+
+    def initialize(remote_host, remote_port, local_host = nil, local_port = nil)
+      @remote_host = remote_host
+      @remote_port = remote_port
+      @local_host = local_host
+      @local_port = local_port
+    end
+
+    def local
+      join_host_port(local_host, local_port)
+    end
+
+    def remote
+      join_host_port(remote_host, remote_port)
+    end
+
+    def check(timeout: 10)
+      Socket.tcp(
+        remote_host, remote_port,
+        local_host, local_port,
+        connect_timeout: timeout
+      ) do |sock|
+        @local_port, @local_host = Socket.unpack_sockaddr_in(sock.local_address)
+        @remote_port, @remote_host = Socket.unpack_sockaddr_in(sock.remote_address)
+      end
+
+      true
+    rescue => err
+      @error = err
+
+      false
+    end
+
+    private
+
+    def join_host_port(host, port)
+      host = "[#{host}]" if host.include?(':')
+
+      "#{host}:#{port}"
+    end
+  end
+end