From 1b08036a0bdc8ee07c8f72aaa5a099b8f504b760 Mon Sep 17 00:00:00 2001
From: Asim Aslam <asim@aslam.me>
Date: Tue, 24 Sep 2019 18:32:35 +0100
Subject: [PATCH] add create options

---
 runtime/default.go | 40 ++++++++++++++++++++++++++++++----------
 runtime/options.go | 27 +++++++++++++++++++++++++++
 runtime/runtime.go |  6 +++---
 3 files changed, 60 insertions(+), 13 deletions(-)
 create mode 100644 runtime/options.go

diff --git a/runtime/default.go b/runtime/default.go
index 9d4f6288..af9772d9 100644
--- a/runtime/default.go
+++ b/runtime/default.go
@@ -2,7 +2,6 @@ package runtime
 
 import (
 	"errors"
-	"os"
 	"strings"
 	"sync"
 	"time"
@@ -50,13 +49,25 @@ func newRuntime() *runtime {
 	}
 }
 
-func newService(s *Service) *service {
-	parts := strings.Split(s.Exec, " ")
-	exec := parts[0]
-	args := []string{}
+func newService(s *Service, c CreateOptions) *service {
+	var exec string
+	var args []string
 
-	if len(parts) > 1 {
-		args = parts[1:]
+	if len(s.Exec) > 0 {
+		parts := strings.Split(s.Exec, " ")
+		exec = parts[0]
+		args = []string{}
+
+		if len(parts) > 1 {
+			args = parts[1:]
+		}
+	} else {
+		// set command
+		exec = c.Command[0]
+		// set args
+		if len(c.Command) > 1 {
+			args = c.Command[1:]
+		}
 	}
 
 	return &service{
@@ -67,7 +78,7 @@ func newService(s *Service) *service {
 				Name: s.Name,
 				Path: exec,
 			},
-			Env:  os.Environ(),
+			Env:  c.Env,
 			Args: args,
 		},
 	}
@@ -189,7 +200,7 @@ func (r *runtime) run() {
 	}
 }
 
-func (r *runtime) Create(s *Service) error {
+func (r *runtime) Create(s *Service, opts ...CreateOption) error {
 	r.Lock()
 	defer r.Unlock()
 
@@ -197,8 +208,17 @@ func (r *runtime) Create(s *Service) error {
 		return errors.New("service already registered")
 	}
 
+	var options CreateOptions
+	for _, o := range opts {
+		o(&options)
+	}
+
+	if len(s.Exec) == 0 && len(options.Command) == 0 {
+		return errors.New("missing exec command")
+	}
+
 	// save service
-	r.services[s.Name] = newService(s)
+	r.services[s.Name] = newService(s, options)
 
 	// push into start queue
 	r.start <- r.services[s.Name]
diff --git a/runtime/options.go b/runtime/options.go
new file mode 100644
index 00000000..99ae40c5
--- /dev/null
+++ b/runtime/options.go
@@ -0,0 +1,27 @@
+package runtime
+
+type CreateOption func(o *CreateOptions)
+
+type CreateOptions struct {
+	// command to execute including args
+	Command []string
+	// Environment to configure
+	Env []string
+}
+
+// Command specifies the command to execute
+func WithCommand(c string, args ...string) CreateOption {
+	return func(o *CreateOptions) {
+		// set command
+		o.Command = []string{c}
+		// set args
+		o.Command = append(o.Command, args...)
+	}
+}
+
+// Env sets the created service env
+func WithEnv(env []string) CreateOption {
+	return func(o *CreateOptions) {
+		o.Env = env
+	}
+}
diff --git a/runtime/runtime.go b/runtime/runtime.go
index 9a306b63..63216867 100644
--- a/runtime/runtime.go
+++ b/runtime/runtime.go
@@ -4,7 +4,7 @@ package runtime
 // Runtime is a service runtime manager
 type Runtime interface {
 	// Registers a service
-	Create(*Service) error
+	Create(*Service, ...CreateOption) error
 	// Remove a service
 	Delete(*Service) error
 	// starts the runtime
@@ -28,8 +28,8 @@ var (
 	DefaultRuntime = newRuntime()
 )
 
-func Create(s *Service) error {
-	return DefaultRuntime.Create(s)
+func Create(s *Service, opts ...CreateOption) error {
+	return DefaultRuntime.Create(s, opts...)
 }
 
 func Delete(s *Service) error {