Cleaned up repo + added README

Author: erwinvaneyk

Dockerfile

@@ -6,8 +6,8 @@ COPY . .
 # Future: Speed up builds by also copying the mod cache ($GOPATH/pkg/mod)
 
 ENV GO111MODULE=on
-RUN go get
 WORKDIR /go/src/github.com/erwinvaneyk/simfaas/cmd/simfission
+RUN go get
 RUN CGO_ENABLED=0 go build \
     -gcflags=-trimpath="/go/src/github.com/erwinvaneyk/simfaas" \
     -asmflags=-trimpath="/go/src/github.com/erwinvaneyk/simfaas" \

Makefile

@@ -1,7 +1,6 @@
 REPO=docker.io/erwinvaneyk
 IMAGE=simfission
 VERSION=latest
-ROOT_DIR=$(dirname $0)
 
 .PHONY: publish test build install
 

README.md

@@ -1 +1,21 @@
-# simfaas
+# SimFaaS
+
+SimFaaS is aimed to be a generic FaaS emulator/simulator (though currently it 
+is just an emulator). The goal is to be able to evaluate key metrics, such as 
+runtime, cold start duration and resource cost, in FaaS platforms.
+
+## Building
+
+See Makefile.
+
+## Fission
+
+SimFaaS includes a specific implementation for Fission called: **SimFission**.
+SimFission is a wrapper on top of simfaas that emulates a part of the
+API of Fission.
+
+It currently emulates the following part of the (web) API:
+1. Resolving a function name to a service.
+2. Tapping of a service.
+3. Executing a fission function.
+4. Getting info for a given function.

cmd/simfission/simfission.go

@@ -12,9 +12,8 @@ import (
 	"time"
 )
 
-// simfaas - is a very simple mock of a FaaS platform to implement the sleep function with minimal interference
-
 var (
+	// buildTime is a UNIX datetime that should be injected at build time.
 	buildTime string // UNIX
 
 	//
@@ -82,7 +81,7 @@ func main() {
 	// Parse arguments
 	coldStart := flag.Duration("cold-start", 0, "The default cold start duration")
 	keepWarm := flag.Duration("keep-warm", 0, "How long the function should be kept warm after an execution.")
-	addr := flag.String("addr", ":8888", "Address to bind the server to.")
+	addr := flag.String("addr", ":8888", "Address serve the API on.")
 	flag.Parse()
 	log.Printf("simfission %s", buildTime)
 
@@ -108,6 +107,7 @@ func main() {
 	if err := fission.Start(); err != nil {
 		log.Fatalf("Failed to start FaaS simulator: %v", err)
 	}
+	defer fission.Close()
 
 	// Publish FaaS simulator resource usage to Prometheus
 	go func() {

fission.go

@@ -13,12 +13,28 @@ import (
 	`time`
 )
 
+// Fission is a wrapper on top of simfaas that emulates a part of the
+// interface of Fission.
 type Fission struct {
 	Platform                 *Platform
 	FnFactory                func(name string) *FunctionConfig
+	
+	// CreateUndefinedFunctions enables, if set to true,
+	// the automatic creation of a function if it is called.
 	CreateUndefinedFunctions bool
 }
 
+func (f *Fission) Start() error {
+	return f.Platform.Start()
+}
+
+func (f *Fission) Close() error {
+	return f.Platform.Close()
+}
+
+// GetServiceForFunction emulates the mapping of a function to a service
+// name/host. Currently it just returns the name of the function as the
+// service name.
 func (f *Fission) GetServiceForFunction(fnName string) (string, error) {
 	f.createIfUndefined(fnName)
 	fn, ok := f.Platform.Get(fnName)
@@ -28,7 +44,10 @@ func (f *Fission) GetServiceForFunction(fnName string) (string, error) {
 	return fn.name, nil
 }
 
-// We assume that url is just the function name
+// TapService deploys (or keeps deployed) a function instance for the function.
+//
+// Note: similar as in GetServiceForFunction, we assume that the service url is
+// just the function name.
 func (f *Fission) TapService(svcURL string) error {
 	if len(svcURL) == 0 {
 		return errors.New("no url provided to tap")
@@ -48,6 +67,15 @@ func (f *Fission) TapService(svcURL string) error {
 	return nil
 }
 
+// Run emulates the execution of a Fission Function.
+//
+// If the runtime is not nil it will be used to override the runtime
+// specified in the config of the function.
+func (f *Fission) Run(fnName string, runtime *time.Duration) (*ExecutionReport, error) {
+	f.createIfUndefined(fnName)
+	return f.Platform.Run(fnName, runtime)
+}
+
 func (f *Fission) Serve() http.Handler {
 	handler := &RegexpHandler{}
 	handler.HandleFunc(regexp.MustCompile("/v2/functions/.*"), f.HandleFunctionsGet)
@@ -57,7 +85,8 @@ func (f *Fission) Serve() http.Handler {
 	return handler
 }
 
-// /v2/getServiceForFunction
+// HandleGetServiceForFunction emulates the /v2/getServiceForFunction
+// Fission endpoint.
 func (f *Fission) HandleGetServiceForFunction(w http.ResponseWriter, r *http.Request) {
 	bs, err := ioutil.ReadAll(r.Body)
 	r.Body.Close()
@@ -81,11 +110,7 @@ func (f *Fission) HandleGetServiceForFunction(w http.ResponseWriter, r *http.Req
 	w.Write([]byte(svc))
 }
 
-func (f *Fission) Start() error {
-	return f.Platform.Start()
-}
-
-// /v2/tapService
+// HandleTapService emulates the /v2/tapService Fission endpoint.
 func (f *Fission) HandleTapService(w http.ResponseWriter, r *http.Request) {
 	bs, err := ioutil.ReadAll(r.Body)
 	defer r.Body.Close()
@@ -105,19 +130,22 @@ func (f *Fission) HandleTapService(w http.ResponseWriter, r *http.Request) {
 	w.WriteHeader(http.StatusOK)
 }
 
-// /v2/functions/.*
+// HandleFunctionsGet emulates the /v2/functions/.* Fission endpoints.
+// Currently it simply returns an empty map.
 func (f *Fission) HandleFunctionsGet(w http.ResponseWriter, r *http.Request) {
 	w.WriteHeader(http.StatusOK)
 	w.Write([]byte("{}"))
 }
 
-// /fission-function/
+// HandleFunctionRun emulates the /fission-function/.* Fission endpoints.
+//
+// It checks for the presence of the runtime query parameter,
+// which allows you to override the runtime of the function.
 func (f *Fission) HandleFunctionRun(w http.ResponseWriter, r *http.Request) {
 	// Parse arguments: fnname, runtime
 	var seconds float64
 	var err error
 	if queryRuntime := r.URL.Query().Get("runtime"); len(queryRuntime) > 0 {
-		// Read query
 		seconds, err = strconv.ParseFloat(queryRuntime, 64)
 		if err != nil {
 			http.Error(w, err.Error(), http.StatusBadRequest)
@@ -126,22 +154,18 @@ func (f *Fission) HandleFunctionRun(w http.ResponseWriter, r *http.Request) {
 	}
 	runtime := time.Duration(seconds * float64(time.Second))
 	fnName := getFunctionNameFromUrl(r.URL)
-	f.createIfUndefined(fnName)
 
-	// Run function
-	report, err := f.Platform.Run(fnName, &runtime)
+	report, err := f.Run(fnName, &runtime)
 	if err != nil {
 		http.Error(w, err.Error(), http.StatusBadRequest)
 		return
 	}
 
-	// Simulate runtime
-	result, _ := json.Marshal(map[string]interface{}{
-		"started_at":  report.StartedAt.UnixNano(),
-		"finished_at": report.FinishedAt.UnixNano(),
-		"coldStart":   report.ColdStart.Nanoseconds(),
-		"runtime":     report.Runtime.Nanoseconds(),
-	})
+	result, err := json.Marshal(report)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
 	w.WriteHeader(http.StatusOK)
 	w.Write(result)
 }
@@ -162,8 +186,6 @@ type ObjectMeta struct {
 	// Namespace string `json:"namespace,omitempty" protobuf:"bytes,3,opt,name=namespace"`
 }
 
-var fnUrlRegEx = regexp.MustCompile("/(.*)$")
-
 func getFunctionNameFromUrl(url *url.URL) string {
 	return url.Path[strings.LastIndex(url.Path, "/")+1:]
 }

fission_test.go

@@ -5,8 +5,10 @@ import (
 	`testing`
 )
 
-func TestFission_Run(t *testing.T) {
-	simFission := NewFission(0, 0)
+func TestFission_Setup(t *testing.T) {
+	simFission := Fission{
+		Platform: New(),
+	}
 	srv := httptest.NewServer(simFission.Serve())
-	defer srv.Close()
+	srv.Close()
 }

httputil.go

@@ -5,15 +5,8 @@ import (
 	`regexp`
 )
 
-//
-// To enable wildcards
-//
-
-type route struct {
-	pattern *regexp.Regexp
-	handler http.Handler
-}
-
+// RegexpHandler is simple http.Handler to enable the use of
+// wildcards in routes.
 type RegexpHandler struct {
 	routes []*route
 }
@@ -38,3 +31,8 @@ func (h *RegexpHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	// no pattern matched; send 404 response
 	http.NotFound(w, r)
 }
+
+type route struct {
+	pattern *regexp.Regexp
+	handler http.Handler
+}

simfaas.go

@@ -28,10 +28,10 @@ type FunctionConfig struct {
 }
 
 type ExecutionReport struct {
-	ColdStart  time.Duration
-	Runtime    time.Duration
-	StartedAt  time.Time
-	FinishedAt time.Time
+	ColdStart  time.Duration `json:"cold_start"`
+	Runtime    time.Duration `json:"runtime"`
+	StartedAt  time.Time     `json:"started_at"`
+	FinishedAt time.Time     `json:"finished_at"`
 }
 
 type Function struct {
@@ -47,8 +47,8 @@ type Function struct {
 	// active reports the number of executions of this function currently running.
 	active atomic.Uint32
 
-	// queued reports the number of executions of this function currently queued, waiting for instances to free up or
-	// additional to be deployed.
+	// queued reports the number of executions of this function currently queued,
+	// waiting for instances to free up or additional to be deployed.
 	queued atomic.Uint32
 }
 
@@ -136,9 +136,10 @@ func (p *Platform) cleanup(fn *Function) {
 	fn.instances.Store(0)
 }
 
-// Run emulates a function execution in a synchronous way, sleeping for the entire executionRuntime
+// Run emulates a function execution in a synchronous way,
+// sleeping for the entire executionRuntime.
 //
-// TODO handle inputs and outputs
+// TODO emulate inputs and outputs
 func (p *Platform) Run(fnName string, executionRuntime *time.Duration) (*ExecutionReport, error) {
 	startedAt := time.Now()
 	// Find the function