Allow enabling gitlab-shell "discover"-feature

This adds the possibility to enable features for GitLab shell.

The first feature being recognized is "Discover": It's the command
that is executed when running `ssh git@gitlab.example.com` and is
called without a command.

The gitlab key id or username is already parsed from the command line
arguments.

Currently we only support communicating with GitLab-rails using unix
sockets. So features will not be enabled if the GitLab-url is using a
different protocol. The url for this read from the config yaml.

Pending ruby-specs have been added for the gitlab-shell command.

Refactor to have separate command packages

1 files changed, 35 insertions, 0 deletions

diff --git a/go/internal/command/command.go b/go/internal/command/command.go
new file mode 100644
index 0000000..cb2acdc
--- /dev/null
+++ b/go/internal/command/command.go
@@ -0,0 +1,35 @@
+package command
+
+import (
+	"gitlab.com/gitlab-org/gitlab-shell/go/internal/command/commandargs"
+	"gitlab.com/gitlab-org/gitlab-shell/go/internal/command/discover"
+	"gitlab.com/gitlab-org/gitlab-shell/go/internal/command/fallback"
+	"gitlab.com/gitlab-org/gitlab-shell/go/internal/config"
+)
+
+type Command interface {
+	Execute() error
+}
+
+func New(arguments []string, config *config.Config) (Command, error) {
+	args, err := commandargs.Parse(arguments)
+
+	if err != nil {
+		return nil, err
+	}
+
+	if config.FeatureEnabled(string(args.CommandType)) {
+		return buildCommand(args, config), nil
+	}
+
+	return &fallback.Command{}, nil
+}
+
+func buildCommand(args *commandargs.CommandArgs, config *config.Config) Command {
+	switch args.CommandType {
+	case commandargs.Discover:
+		return &discover.Command{Config: config, Args: args}
+	}
+
+	return nil
+}