Don't fall back to ruby for non SSH connections

When SSH_CONNECTION is not set, we don't fall back to ruby, but
instead fail directly in go writing the error to stderr.

go/cmd/gitlab-shell/main.go

@@ -41,17 +41,16 @@ func main() {
 
 	cmd, err := command.New(os.Args, config)
 	if err != nil {
-		// Failed to build the command, fall back to ruby.
 		// For now this could happen if `SSH_CONNECTION` is not set on
 		// the environment
-		fmt.Fprintf(os.Stderr, "Failed to build command: %v\n", err)
-		execRuby()
+		fmt.Fprintf(os.Stderr, "%v\n", err)
+		os.Exit(1)
 	}
 
 	// The command will write to STDOUT on execution or replace the current
 	// process in case of the `fallback.Command`
 	if err = cmd.Execute(); err != nil {
-		fmt.Fprintf(os.Stderr, "%s\n", err)
+		fmt.Fprintf(os.Stderr, "%v\n", err)
 		os.Exit(1)
 	}
 }

go/internal/command/commandargs/command_args.go

@@ -37,15 +37,15 @@ func Parse(arguments []string) (*CommandArgs, error) {
 	return info, nil
 }
 
-func (info *CommandArgs) parseWho(arguments []string) {
+func (c *CommandArgs) parseWho(arguments []string) {
 	for _, argument := range arguments {
 		if keyId := tryParseKeyId(argument); keyId != "" {
-			info.GitlabKeyId = keyId
+			c.GitlabKeyId = keyId
 			break
 		}
 
 		if username := tryParseUsername(argument); username != "" {
-			info.GitlabUsername = username
+			c.GitlabUsername = username
 			break
 		}
 	}

spec/gitlab_shell_gitlab_shell_spec.rb

 require_relative 'spec_helper'
 
+require 'open3'
+
 describe 'bin/gitlab-shell' do
   def original_root_path
     ROOT_PATH
@@ -60,14 +62,14 @@ describe 'bin/gitlab-shell' do
   shared_examples 'results with keys' do
     # Basic valid input
     it 'succeeds and prints username when a valid known key id is given' do
-      output, status = run!(["key-100"])
+      output, _, status = run!(["key-100"])
 
       expect(output).to eq("Welcome to GitLab, @someuser!\n")
       expect(status).to be_success
     end
 
     it 'succeeds and prints username when a valid known username is given' do
-      output, status = run!(["username-someuser"])
+      output, _, status = run!(["username-someuser"])
 
       expect(output).to eq("Welcome to GitLab, @someuser!\n")
       expect(status).to be_success
@@ -75,52 +77,51 @@ describe 'bin/gitlab-shell' do
 
     # Valid but unknown input
     it 'succeeds and prints Anonymous when a valid unknown key id is given' do
-      output, status = run!(["key-12345"])
+      output, _, status = run!(["key-12345"])
 
       expect(output).to eq("Welcome to GitLab, Anonymous!\n")
       expect(status).to be_success
     end
 
     it 'succeeds and prints Anonymous when a valid unknown username is given' do
-      output, status = run!(["username-unknown"])
+      output, _, status = run!(["username-unknown"])
 
       expect(output).to eq("Welcome to GitLab, Anonymous!\n")
       expect(status).to be_success
     end
 
-    # Invalid input. TODO: capture stderr & compare
     it 'gets an ArgumentError on invalid input (empty)' do
-      output, status = run!([])
+      _, stderr, status = run!([])
 
-      expect(output).to eq("")
+      expect(stderr).to match(/who='' is invalid/)
       expect(status).not_to be_success
     end
 
     it 'gets an ArgumentError on invalid input (unknown)' do
-      output, status = run!(["whatever"])
+      _, stderr, status = run!(["whatever"])
 
-      expect(output).to eq("")
+      expect(stderr).to match(/who='' is invalid/)
       expect(status).not_to be_success
     end
 
     it 'gets an ArgumentError on invalid input (multiple unknown)' do
-      output, status = run!(["this", "is", "all", "invalid"])
+      _, stderr, status = run!(["this", "is", "all", "invalid"])
 
-      expect(output).to eq("")
+      expect(stderr).to match(/who='' is invalid/)
       expect(status).not_to be_success
     end
 
     # Not so basic valid input
     # (https://gitlab.com/gitlab-org/gitlab-shell/issues/145)
     it 'succeeds and prints username when a valid known key id is given in the middle of other input' do
-      output, status = run!(["-c/usr/share/webapps/gitlab-shell/bin/gitlab-shell", "key-100", "2foo"])
+      output, _, status = run!(["-c/usr/share/webapps/gitlab-shell/bin/gitlab-shell", "key-100", "2foo"])
 
       expect(output).to eq("Welcome to GitLab, @someuser!\n")
       expect(status).to be_success
     end
 
     it 'succeeds and prints username when a valid known username is given in the middle of other input' do
-      output, status = run!(["-c/usr/share/webapps/gitlab-shell/bin/gitlab-shell", "username-someuser" ,"foo"])
+      output, _, status = run!(["-c/usr/share/webapps/gitlab-shell/bin/gitlab-shell", "username-someuser" ,"foo"])
 
       expect(output).to eq("Welcome to GitLab, @someuser!\n")
       expect(status).to be_success
@@ -144,24 +145,27 @@ describe 'bin/gitlab-shell' do
       )
     end
 
-
-
     it_behaves_like 'results with keys' do
       before do
         pending
       end
     end
+
+    it 'outputs "Only ssh allowed"' do
+      _, stderr, status = run!(["-c/usr/share/webapps/gitlab-shell/bin/gitlab-shell", "username-someuser"], env: {})
+
+      expect(stderr).to eq("Only ssh allowed\n")
+      expect(status).not_to be_success
+    end
   end
 
-  def run!(args)
+  def run!(args, env: {'SSH_CONNECTION' => 'fake'})
     cmd = [
       gitlab_shell_path,
       args
-    ].flatten.compact
-
-    output = IO.popen({'SSH_CONNECTION' => 'fake'}, cmd, &:read)
+    ].flatten.compact.join(' ')
 
-    [output, $?]
+    Open3.capture3(env, cmd)
   end
 
   def write_config(config)