From bcf9b230be6d74c71567fd0771b31d47d8dd39c7 Mon Sep 17 00:00:00 2001 From: Brian Picciano Date: Thu, 21 Jan 2021 17:22:53 -0700 Subject: build the blog with nix --- assets/component-oriented-design/v2/main.go | 320 ---------------------------- assets/component-oriented-design/v2/main.md | 4 - 2 files changed, 324 deletions(-) delete mode 100644 assets/component-oriented-design/v2/main.go delete mode 100644 assets/component-oriented-design/v2/main.md (limited to 'assets/component-oriented-design/v2') diff --git a/assets/component-oriented-design/v2/main.go b/assets/component-oriented-design/v2/main.go deleted file mode 100644 index fb5773c..0000000 --- a/assets/component-oriented-design/v2/main.go +++ /dev/null @@ -1,320 +0,0 @@ -package main - -import ( - "encoding/json" - "errors" - "flag" - "fmt" - "io" - "io/ioutil" - "log" - "math/rand" - "net" - "net/http" - "os" - "sort" - "strconv" - "sync" - "time" -) - -// Logger describes a simple component used for printing log lines. -type Logger interface { - Printf(string, ...interface{}) -} - -//////////////////////////////////////////////////////////////////////////////// -// The scoreboard component - -// File wraps the standard os.File type. -type File interface { - io.ReadWriter - Truncate(int64) error - Seek(int64, int) (int64, error) -} - -// scoreboard loads player scores from a save file, tracks score updates, and -// periodically saves those scores back to the save file. -type scoreboard struct { - file File - scoresM map[string]int - scoresLock sync.Mutex - - pointsOnCorrect, pointsOnIncorrect int - - // this field will only be set in tests, and is used to synchronize with the - // the for-select loop in saveLoop. - saveLoopWaitCh chan struct{} -} - -// newScoreboard initializes a scoreboard using scores saved in the given File -// (which may be empty). The scoreboard will rewrite the save file with the -// latest scores everytime saveTicker is written to. -func newScoreboard(file File, saveTicker <-chan time.Time, logger Logger, pointsOnCorrect, pointsOnIncorrect int) (*scoreboard, error) { - fileBody, err := ioutil.ReadAll(file) - if err != nil { - return nil, fmt.Errorf("reading saved scored: %w", err) - } - - scoresM := map[string]int{} - if len(fileBody) > 0 { - if err := json.Unmarshal(fileBody, &scoresM); err != nil { - return nil, fmt.Errorf("decoding saved scores: %w", err) - } - } - - scoreboard := &scoreboard{ - file: file, - scoresM: scoresM, - pointsOnCorrect: pointsOnCorrect, - pointsOnIncorrect: pointsOnIncorrect, - saveLoopWaitCh: make(chan struct{}), - } - - go scoreboard.saveLoop(saveTicker, logger) - - return scoreboard, nil -} - -func (s *scoreboard) guessedCorrect(name string) int { - s.scoresLock.Lock() - defer s.scoresLock.Unlock() - - s.scoresM[name] += s.pointsOnCorrect - return s.scoresM[name] -} - -func (s *scoreboard) guessedIncorrect(name string) int { - s.scoresLock.Lock() - defer s.scoresLock.Unlock() - - s.scoresM[name] += s.pointsOnIncorrect - return s.scoresM[name] -} - -func (s *scoreboard) scores() map[string]int { - s.scoresLock.Lock() - defer s.scoresLock.Unlock() - - scoresCp := map[string]int{} - for name, score := range s.scoresM { - scoresCp[name] = score - } - - return scoresCp -} - -func (s *scoreboard) save() error { - scores := s.scores() - if _, err := s.file.Seek(0, 0); err != nil { - return fmt.Errorf("seeking to start of save file: %w", err) - } else if err := s.file.Truncate(0); err != nil { - return fmt.Errorf("truncating save file: %w", err) - } else if err := json.NewEncoder(s.file).Encode(scores); err != nil { - return fmt.Errorf("encoding scores to save file: %w", err) - } - return nil -} - -func (s *scoreboard) saveLoop(ticker <-chan time.Time, logger Logger) { - for { - select { - case <-ticker: - if err := s.save(); err != nil { - logger.Printf("error saving scoreboard to file: %v", err) - } - case <-s.saveLoopWaitCh: - // test will unblock, nothing to do here. - } - } -} - -//////////////////////////////////////////////////////////////////////////////// -// The httpHandlers component - -// Scoreboard describes the scoreboard component from the point of view of the -// httpHandler component (which only needs a subset of scoreboard's methods). -type Scoreboard interface { - guessedCorrect(name string) int - guessedIncorrect(name string) int - scores() map[string]int -} - -// RandSrc describes a randomness component which can produce random integers. -type RandSrc interface { - Int() int -} - -// httpHandlers implements the http.HandlerFuncs used by the httpServer. -type httpHandlers struct { - scoreboard Scoreboard - randSrc RandSrc - logger Logger - - mux *http.ServeMux - n int - nLock sync.Mutex -} - -func newHTTPHandlers(scoreboard Scoreboard, randSrc RandSrc, logger Logger) *httpHandlers { - n := randSrc.Int() - logger.Printf("first n is %v", n) - - httpHandlers := &httpHandlers{ - scoreboard: scoreboard, - randSrc: randSrc, - logger: logger, - mux: http.NewServeMux(), - n: n, - } - - httpHandlers.mux.HandleFunc("/guess", httpHandlers.handleGuess) - httpHandlers.mux.HandleFunc("/scores", httpHandlers.handleScores) - - return httpHandlers -} - -func (h *httpHandlers) ServeHTTP(rw http.ResponseWriter, r *http.Request) { - h.mux.ServeHTTP(rw, r) -} - -func (h *httpHandlers) handleGuess(rw http.ResponseWriter, r *http.Request) { - r.Header.Set("Content-Type", "text/plain") - - name := r.FormValue("name") - nStr := r.FormValue("n") - if name == "" || nStr == "" { - http.Error(rw, `"name" and "n" GET args are required`, http.StatusBadRequest) - return - } - - n, err := strconv.Atoi(nStr) - if err != nil { - http.Error(rw, err.Error(), http.StatusBadRequest) - return - } - - h.nLock.Lock() - defer h.nLock.Unlock() - - if h.n == n { - newScore := h.scoreboard.guessedCorrect(name) - h.n = h.randSrc.Int() - h.logger.Printf("new n is %v", h.n) - rw.WriteHeader(http.StatusOK) - fmt.Fprintf(rw, "Correct! Your score is now %d\n", newScore) - return - } - - hint := "higher" - if h.n < n { - hint = "lower" - } - - newScore := h.scoreboard.guessedIncorrect(name) - rw.WriteHeader(http.StatusBadRequest) - fmt.Fprintf(rw, "Try %s. Your score is now %d\n", hint, newScore) -} - -func (h *httpHandlers) handleScores(rw http.ResponseWriter, r *http.Request) { - r.Header.Set("Content-Type", "text/plain") - - h.nLock.Lock() - defer h.nLock.Unlock() - - type scoreTup struct { - name string - score int - } - - scores := h.scoreboard.scores() - scoresTups := make([]scoreTup, 0, len(scores)) - for name, score := range scores { - scoresTups = append(scoresTups, scoreTup{name, score}) - } - - sort.Slice(scoresTups, func(i, j int) bool { - return scoresTups[i].score > scoresTups[j].score - }) - - for _, scoresTup := range scoresTups { - fmt.Fprintf(rw, "%s: %d\n", scoresTup.name, scoresTup.score) - } -} - -//////////////////////////////////////////////////////////////////////////////// -// The httpServer component. - -type httpServer struct { - httpServer *http.Server - errCh chan error -} - -func newHTTPServer(listener net.Listener, httpHandlers *httpHandlers, logger Logger) *httpServer { - loggingHandler := http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) { - ip, _, _ := net.SplitHostPort(r.RemoteAddr) - logger.Printf("HTTP request -> %s %s %s", ip, r.Method, r.URL.String()) - httpHandlers.ServeHTTP(rw, r) - }) - - server := &httpServer{ - httpServer: &http.Server{ - Handler: loggingHandler, - }, - errCh: make(chan error, 1), - } - - go func() { - err := server.httpServer.Serve(listener) - if errors.Is(err, http.ErrServerClosed) { - err = nil - } - server.errCh <- err - }() - - return server -} - -//////////////////////////////////////////////////////////////////////////////// -// main - -func main() { - saveFilePath := flag.String("save-file", "./save.json", "File used to save scores") - listenAddr := flag.String("listen-addr", ":8888", "Address to listen for HTTP requests on") - saveInterval := flag.Duration("save-interval", 5*time.Second, "How often to resave scores") - pointsOnCorrect := flag.Int("points-on-correct", 1000, "Amount to change a user's score by upon a correct score") - pointsOnIncorrect := flag.Int("points-on-incorrect", -1, "Amount to change a user's score by upon an incorrect score") - flag.Parse() - - logger := log.New(os.Stdout, "", log.LstdFlags) - - logger.Printf("opening scoreboard save file %q", *saveFilePath) - file, err := os.OpenFile(*saveFilePath, os.O_RDWR|os.O_CREATE, 0644) - if err != nil { - logger.Fatalf("failed to open file %q: %v", *saveFilePath, err) - } - - saveTicker := time.NewTicker(*saveInterval) - randSrc := rand.New(rand.NewSource(time.Now().UnixNano())) - - logger.Printf("initializing scoreboard") - scoreboard, err := newScoreboard(file, saveTicker.C, logger, *pointsOnCorrect, *pointsOnIncorrect) - if err != nil { - logger.Fatalf("failed to initialize scoreboard: %v", err) - } - - logger.Printf("listening on %q", *listenAddr) - listener, err := net.Listen("tcp", *listenAddr) - if err != nil { - logger.Fatalf("failed to listen on %q: %v", *listenAddr, err) - } - - logger.Printf("setting up HTTP handlers") - httpHandlers := newHTTPHandlers(scoreboard, randSrc, logger) - - logger.Printf("serving HTTP requests") - newHTTPServer(listener, httpHandlers, logger) - - logger.Printf("initialization done") - select {} // block forever -} diff --git a/assets/component-oriented-design/v2/main.md b/assets/component-oriented-design/v2/main.md deleted file mode 100644 index 37346c6..0000000 --- a/assets/component-oriented-design/v2/main.md +++ /dev/null @@ -1,4 +0,0 @@ ---- -layout: code -include: main.go ---- -- cgit v1.2.3