fn: more functionality into fn-test-utils (#752)

read/write a file on disk, alloc/leak memory.

images/fn-test-utils/fn-test-utils.go

@@ -4,11 +4,13 @@ import (
 	"context"
 	"encoding/json"
 	"io"
+	"io/ioutil"
 	"log"
+	"net/http"
+	"os"
 	"time"
 
 	fdk "github.com/fnproject/fdk-go"
-	"net/http"
 )
 
 type AppRequest struct {
@@ -24,18 +26,48 @@ type AppRequest struct {
 	IsDebug bool `json:"isDebug,omitempty"`
 	// simulate crash
 	IsCrash bool `json:"isCrash,omitempty"`
+	// read a file from disk
+	ReadFile string `json:"readFile,omitempty"`
+	// fill created with with zero bytes of specified size
+	ReadFileSize int `json:"readFileSize,omitempty"`
+	// create a file on disk
+	CreateFile string `json:"createFile,omitempty"`
+	// fill created with with zero bytes of specified size
+	CreateFileSize int `json:"createFileSize,omitempty"`
+	// allocate RAM and hold until next request
+	AllocateMemory int `json:"allocateMemory,om itempty"`
+	// leak RAM forever
+	LeakMemory int `json:"leakMemory,omitempty"`
 	// TODO: simulate slow read/slow write
-	// TODO: simulate partial write/read
-	// TODO: simulate mem leak
-	// TODO: simulate high cpu usage
-	// TODO: simulate high mem usage
+	// TODO: simulate partial IO write/read
+	// TODO: simulate high cpu usage (async and sync)
 	// TODO: simulate large body upload/download
+	// TODO: infinite loop
 }
 
+// ever growing memory leak chunks
+var Leaks []*[]byte
+
+// memory to hold on to at every request, new requests overwrite it.
+var Hold []byte
+
 type AppResponse struct {
 	Request AppRequest        `json:"request"`
 	Headers http.Header       `json:"header"`
 	Config  map[string]string `json:"config"`
+	Data    map[string]string `json:"data"`
+}
+
+func init() {
+	Leaks = make([]*[]byte, 0, 0)
+}
+
+func getTotalLeaks() int {
+	total := 0
+	for idx, _ := range Leaks {
+		total += len(*(Leaks[idx]))
+	}
+	return total
 }
 
 func AppHandler(ctx context.Context, in io.Reader, out io.Writer) {
@@ -59,11 +91,6 @@ func AppHandler(ctx context.Context, in io.Reader, out io.Writer) {
 		time.Sleep(time.Duration(request.SleepTime) * time.Millisecond)
 	}
 
-	// simulate crash
-	if request.IsCrash {
-		panic("Crash requested")
-	}
-
 	// custom response code
 	if request.ResponseCode != 0 {
 		fdk.WriteStatus(out, request.ResponseCode)
@@ -78,7 +105,54 @@ func AppHandler(ctx context.Context, in io.Reader, out io.Writer) {
 		fdk.SetHeader(out, "Content-Type", "application/json")
 	}
 
+	data := make(map[string]string)
+
+	// read a file
+	if request.ReadFile != "" {
+		if request.IsDebug {
+			log.Printf("Reading file %s", request.ReadFile)
+		}
+		out, err := readFile(request.ReadFile, request.ReadFileSize)
+		if err != nil {
+			data[request.ReadFile+".read_error"] = err.Error()
+		} else {
+			data[request.ReadFile+".read_output"] = out
+		}
+	}
+
+	// create a file
+	if request.CreateFile != "" {
+		if request.IsDebug {
+			log.Printf("Creating file %s (size: %d)", request.CreateFile, request.CreateFileSize)
+		}
+		err := createFile(request.CreateFile, request.CreateFileSize)
+		if err != nil {
+			data[request.CreateFile+".create_error"] = err.Error()
+		}
+	}
+
+	// handle one time alloc request (hold on to the memory until next request)
+	if request.AllocateMemory != 0 && request.IsDebug {
+		log.Printf("Allocating memory size: %d", request.AllocateMemory)
+	}
+	Hold = getChunk(request.AllocateMemory)
+
+	// leak memory forever
+	if request.LeakMemory != 0 {
+		if request.IsDebug {
+			log.Printf("Leaking memory size: %d total: %d", request.LeakMemory, getTotalLeaks())
+		}
+		chunk := getChunk(request.LeakMemory)
+		Leaks = append(Leaks, &chunk)
+	}
+
+	// simulate crash
+	if request.IsCrash {
+		panic("Crash requested")
+	}
+
 	resp := AppResponse{
+		Data:    data,
 		Request: request,
 		Headers: fnctx.Header,
 		Config:  fnctx.Config,
@@ -90,3 +164,40 @@ func AppHandler(ctx context.Context, in io.Reader, out io.Writer) {
 func main() {
 	fdk.Handle(fdk.HandlerFunc(AppHandler))
 }
+
+func getChunk(size int) []byte {
+	chunk := make([]byte, size)
+	// fill it
+	for idx, _ := range chunk {
+		chunk[idx] = 1
+	}
+	return chunk
+}
+
+func readFile(name string, size int) (string, error) {
+	// read the whole file into memory
+	out, err := ioutil.ReadFile(name)
+	if err != nil {
+		return "", err
+	}
+	// only respond with partion output if requested
+	if size > 0 {
+		return string(out[:size]), nil
+	}
+	return string(out), nil
+}
+
+func createFile(name string, size int) error {
+	f, err := os.Create(name)
+	if err != nil {
+		return err
+	}
+
+	if size > 0 {
+		err := f.Truncate(int64(size))
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}