Moving dep builds into Dockerfile and multi-stage builds.

fn/langs/base.go

@@ -36,6 +36,16 @@ func GetLangHelper(lang string) LangHelper {
 }
 
 type LangHelper interface {
+	// BuildFromImage is the base image to build off, typically funcy/LANG:dev
+	BuildFromImage() string
+	// RunFromImage is the base image to use for deployment (usually smaller than the build images)
+	RunFromImage() string
+	// If set to false, it will use a single Docker build step, rather than multi-stage
+	IsMultiStage() bool
+	// Dockerfile build lines for building dependencies or anything else language specific
+	DockerfileBuildCmds() []string
+	// DockerfileCopyCmds will run in second/final stage of multi-stage build to copy artifacts form the build stage
+	DockerfileCopyCmds() []string
 	// Entrypoint sets the Docker Entrypoint. One of Entrypoint or Cmd is required.
 	Entrypoint() string
 	// Cmd sets the Docker command. One of Entrypoint or Cmd is required.
@@ -54,10 +64,19 @@ type LangHelper interface {
 type BaseHelper struct {
 }
 
-func (h *BaseHelper) Cmd() string                { return "" }
-func (h *BaseHelper) HasBoilerplate() bool       { return false }
-func (h *BaseHelper) GenerateBoilerplate() error { return nil }
+func (h *BaseHelper) BuildFromImage() string        { return "" }
+func (h *BaseHelper) RunFromImage() string          { return h.BuildFromImage() }
+func (h *BaseHelper) IsMultiStage() bool            { return true }
+func (h *BaseHelper) DockerfileBuildCmds() []string { return []string{} }
+func (h *BaseHelper) DockerfileCopyCmds() []string  { return []string{} }
+func (h *BaseHelper) Cmd() string                   { return "" }
+func (lh *BaseHelper) HasPreBuild() bool            { return false }
+func (lh *BaseHelper) PreBuild() error              { return nil }
+func (lh *BaseHelper) AfterBuild() error            { return nil }
+func (h *BaseHelper) HasBoilerplate() bool          { return false }
+func (h *BaseHelper) GenerateBoilerplate() error    { return nil }
 
+// exists checks if a file exists
 func exists(name string) bool {
 	if _, err := os.Stat(name); err != nil {
 		if os.IsNotExist(err) {