Leverage "Component" to model service endpoints (#538)

* Remove Endpoint/Calls in favor of Component

Components can be used to represent endpoints:

```go
		Container("Web Application", "Delivers content to users.", func() {
			Component("Dashboard Endpoint", "Serve dashboard content.", func() {
				Tag("endpoint")
			})
			Uses("Application Database", "Reads from and writes to", "MySQL", Synchronous)
		})
```
`Uses` can target the endpoint alleviating the need for `Calls`:
```go
		Container("Load Balancer", "Distributes requests across the Web Application instances.", func() {
			Uses("Web Application/Dashboard Endpoint", "Routes requests to", "HTTPS", Synchronous)
		})
```

* Cleanup

* Remove unused code

Makefile

@@ -22,7 +22,7 @@ GO_FILES=$(shell find . -type f -name '*.go')
 # Standard dependencies are installed via go get
 DEPEND=\
 	golang.org/x/tools/cmd/goimports@latest \
-	honnef.co/go/tools/cmd/staticcheck@latest \
+	github.com/golangci/golangci-lint/cmd/golangci-lint@latest \
 	github.com/mjibson/esc@latest
 
 all: lint check-generated test
@@ -41,8 +41,8 @@ ifneq ($(GOOS),windows)
 	@if [ "`goimports -l $(GO_FILES) | tee /dev/stderr`" ]; then \
 		echo "^ - Repo contains improperly formatted go files" && echo && exit 1; \
 	fi
-	@if [ "`staticcheck ./... | tee /dev/stderr`" ]; then \
-		echo "^ - staticcheck errors!" && echo && exit 1; \
+	@if [ "`golangci-lint run ./... | tee /dev/stderr`" ]; then \
+		echo "^ - golangci-lint errors!" && echo && exit 1; \
 	fi
 endif
 
@@ -52,12 +52,12 @@ check-generated: generate
   	fi
 
 test:
-	env GO111MODULE=on go test ./...
+	go test ./...
 
 release:
 # First make sure all is clean
 	@git diff-index --quiet HEAD
-	@go mod tidy --compat=1.17
+	@go mod tidy
 
 # Bump version number
 	@sed 's/Major = .*/Major = $(MAJOR)/' pkg/version.go > _tmp && mv _tmp pkg/version.go

cmd/mdl/main.go

@@ -62,13 +62,19 @@ func main() {
 	switch cmd {
 	case "gen":
 		addGlobals(genset)
-		genset.Parse(os.Args[idx:])
+		if err := genset.Parse(os.Args[idx:]); err != nil {
+			fail(err.Error())
+		}
 	case "serve":
 		addGlobals(svrset)
-		svrset.Parse(os.Args[idx:])
+		if err := svrset.Parse(os.Args[idx:]); err != nil {
+			fail(err.Error())
+		}
 	default:
 		addGlobals(gset)
-		gset.Parse(os.Args[idx:])
+		if err := gset.Parse(os.Args[idx:]); err != nil {
+			fail(err.Error())
+		}
 	}
 
 	if *h || *help {
@@ -154,7 +160,7 @@ func printUsage(fss ...*flag.FlagSet) {
 	}
 }
 
-func fail(format string, args ...interface{}) {
+func fail(format string, args ...any) {
 	fmt.Fprintf(os.Stderr, format+"\n", args...)
 	os.Exit(1)
 }

cmd/mdl/serve.go

@@ -31,7 +31,7 @@ type (
 	}
 
 	// Layout is position info saved for one view (diagram)
-	Layout = map[string]interface{}
+	Layout = map[string]any
 
 	// Layouts is a map from view key to the view Layout
 	Layouts = map[string]Layout
@@ -81,7 +81,7 @@ func (s *Server) Serve(outDir string, devmode bool, port int) error {
 	http.HandleFunc("/data/save", func(w http.ResponseWriter, r *http.Request) {
 		id := r.URL.Query().Get("id")
 		if id == "" {
-			http.Error(w, "Param id is missing", http.StatusBadRequest)
+			handleError(w, fmt.Errorf("missing id"))
 			return
 		}
 
@@ -91,9 +91,7 @@ func (s *Server) Serve(outDir string, devmode bool, port int) error {
 		svgFile := path.Join(outDir, id+".svg")
 		f, err := os.Create(svgFile)
 		if err != nil {
-			msg := fmt.Sprintf("Saving failed, can't write to %s: %s!\n", svgFile, err)
-			fmt.Println(msg)
-			http.Error(w, msg, http.StatusInternalServerError)
+			handleError(w, err)
 			return
 		}
 		defer func() { _ = f.Close() }()
@@ -123,6 +121,12 @@ func (s *Server) SetDesign(d *mdl.Design) {
 	s.design = b
 }
 
+// handleError writes the given error to stderr and http.Error.
+func handleError(w http.ResponseWriter, err error) {
+	fmt.Fprintln(os.Stderr, err.Error())
+	http.Error(w, err.Error(), http.StatusInternalServerError)
+}
+
 // loadLayouts lists out directory and reads layout info from SVG files
 // for backwards compatibility, fallback to layout.json
 func loadLayouts(dir string) ([]byte, error) {
@@ -164,7 +168,7 @@ func loadLayouts(dir string) ([]byte, error) {
 		end := bytes.Index(b, endMark)
 		b = b[begin:end]
 
-		var l Layout = make(map[string]interface{})
+		var l Layout = make(map[string]any)
 		err = json.Unmarshal(b, &l)
 		if err != nil {
 			return nil, err

cmd/stz/main.go

@@ -46,7 +46,9 @@ func main() {
 		}
 	}
 done:
-	fs.Parse(os.Args[idx:])
+	if err := fs.Parse(os.Args[idx:]); err != nil {
+		fail(err.Error())
+	}
 
 	pathOrDefault := func(p string) string {
 		if p == "" {
@@ -208,7 +210,7 @@ func put(path, wid, key, secret string, debug bool) error {
 	return c.Put(wid, local)
 }
 
-func fail(format string, args ...interface{}) {
+func fail(format string, args ...any) {
 	fmt.Fprintf(os.Stderr, format+"\n", args...)
 	os.Exit(1)
 }

dsl/deployment.go

@@ -90,7 +90,7 @@ func DeploymentEnvironment(name string, dsl func()) {
 //	        })
 //	    })
 //	})
-func DeploymentNode(name string, args ...interface{}) *expr.DeploymentNode {
+func DeploymentNode(name string, args ...any) *expr.DeploymentNode {
 	if strings.Contains(name, "/") {
 		eval.ReportError("DeploymentNode: name cannot include slashes")
 	}
@@ -168,7 +168,7 @@ func DeploymentNode(name string, args ...interface{}) *expr.DeploymentNode {
 //	        })
 //	    })
 //	})
-func InfrastructureNode(name string, args ...interface{}) *expr.InfrastructureNode {
+func InfrastructureNode(name string, args ...any) *expr.InfrastructureNode {
 	d, ok := eval.Current().(*expr.DeploymentNode)
 	if !ok {
 		eval.IncompatibleDSL()
@@ -241,7 +241,7 @@ func InfrastructureNode(name string, args ...interface{}) *expr.InfrastructureNo
 //	        })
 //	    })
 //	})
-func ContainerInstance(container interface{}, dsl ...func()) *expr.ContainerInstance {
+func ContainerInstance(container any, dsl ...func()) *expr.ContainerInstance {
 	d, ok := eval.Current().(*expr.DeploymentNode)
 	if !ok {
 		eval.IncompatibleDSL()

dsl/design.go

@@ -44,7 +44,7 @@ import (
 //	var _ = Design("My Design", "A great architecture.", func() {
 //	    SoftwareSystem("My Software System")
 //	})
-func Design(args ...interface{}) *expr.Design {
+func Design(args ...any) *expr.Design {
 	_, ok := eval.Current().(eval.TopExpr)
 	if !ok {
 		eval.IncompatibleDSL()

dsl/doc.go

@@ -34,7 +34,7 @@ general shape of the DSL is:
 	│   ├── Prop                            │   ├── AutoLayout
 	│   ├── Uses                            │   ├── AnimationStep
 	│   ├── Delivers                        │   ├── PaperSize
-	│   └─── Container                      │   └── EnterpriseBoundaryVisible
+	│   └── Container                       │   └── EnterpriseBoundaryVisible
 	│       ├── Tag                         ├── SystemContextView
 	│       ├── URL                         │   └──  ... (same as SystemLandsapeView)
 	│       ├── Prop                        ├── ContainerView

dsl/elements.go

@@ -39,7 +39,7 @@ import (
 //	        Delivers("Customer", "Delivers emails to", "SMTP", Synchronous)
 //	    })
 //	})
-func SoftwareSystem(name string, args ...interface{}) *expr.SoftwareSystem {
+func SoftwareSystem(name string, args ...any) *expr.SoftwareSystem {
 	w, ok := eval.Current().(*expr.Design)
 	if !ok {
 		eval.IncompatibleDSL()
@@ -112,7 +112,7 @@ func SoftwareSystem(name string, args ...interface{}) *expr.SoftwareSystem {
 //	        })
 //	    })
 //	})
-func Container(args ...interface{}) *expr.Container {
+func Container(args ...any) *expr.Container {
 	system, ok := eval.Current().(*expr.SoftwareSystem)
 	if !ok {
 		eval.IncompatibleDSL()
@@ -209,7 +209,7 @@ func Container(args ...interface{}) *expr.Container {
 //	        })
 //	    })
 //	})
-func Component(name string, args ...interface{}) *expr.Component {
+func Component(name string, args ...any) *expr.Component {
 	container, ok := eval.Current().(*expr.Container)
 	if !ok {
 		eval.IncompatibleDSL()
@@ -243,7 +243,7 @@ func Component(name string, args ...interface{}) *expr.Component {
 //	func()
 //	"[description]", func()
 //	"[description]", "[technology]", func()
-func parseElementArgs(args ...interface{}) (description, technology string, dsl func(), err error) {
+func parseElementArgs(args ...any) (description, technology string, dsl func(), err error) {
 	if len(args) == 0 {
 		return
 	}

dsl/person.go

@@ -37,7 +37,7 @@ import (
 //	        InteractsWith(Employee)
 //	    })
 //	})
-func Person(name string, args ...interface{}) *expr.Person {
+func Person(name string, args ...any) *expr.Person {
 	w, ok := eval.Current().(*expr.Design)
 	if !ok {
 		eval.IncompatibleDSL()

dsl/relationship.go

@@ -84,7 +84,7 @@ const (
 //	       InteractsWith("Customer", "Sends invoices to", Synchronous)
 //	    })
 //	})
-func Uses(element interface{}, description string, args ...interface{}) {
+func Uses(element any, description string, args ...any) {
 	var src *expr.Element
 	switch e := eval.Current().(type) {
 	case *expr.Person:
@@ -142,7 +142,7 @@ func Uses(element interface{}, description string, args ...interface{}) {
 //	       InteractsWith(Employee, "Sends requests to", "email")
 //	    })
 //	})
-func InteractsWith(person interface{}, description string, args ...interface{}) {
+func InteractsWith(person any, description string, args ...any) {
 	src, ok := eval.Current().(*expr.Person)
 	if !ok {
 		eval.IncompatibleDSL()
@@ -205,7 +205,7 @@ func InteractsWith(person interface{}, description string, args ...interface{})
 //	       Delivers(Customer, "Sends requests to", "email")
 //	    })
 //	})
-func Delivers(person interface{}, description string, args ...interface{}) {
+func Delivers(person any, description string, args ...any) {
 	var src *expr.Element
 	switch e := eval.Current().(type) {
 	case *expr.SoftwareSystem:
@@ -258,7 +258,7 @@ func Description(desc string) {
 
 // uses adds a relationship between the given source and destination. The caller
 // must make sure that the relationship is valid.
-func uses(src *expr.Element, dest interface{}, desc string, args ...interface{}) error {
+func uses(src *expr.Element, dest any, desc string, args ...any) error {
 	var (
 		technology string
 		style      InteractionStyleKind