109 lines
2.6 KiB
Go
109 lines
2.6 KiB
Go
package main
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import (
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"errors"
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"fmt"
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_ "github.com/go-sql-driver/mysql"
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"github.com/gorilla/mux"
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"log"
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"net/http"
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"strconv"
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)
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const DEBUG = true
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func main() {
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err := setup()
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defer teardown()
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if err == nil {
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startServer()
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}
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}
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func setup() error {
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err := InitDb()
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if err != nil {
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return err
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}
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return nil
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}
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func teardown() {
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CloseDb()
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}
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func startServer() {
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port := "8001"
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r := mux.NewRouter()
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r.HandleFunc("/", showCharts).Methods("GET")
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r.HandleFunc("/since/{mins}", showCharts).Methods("GET")
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r.HandleFunc("/data/", sendData).Methods("GET")
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r.HandleFunc("/data/since/{mins}", sendData).Methods("GET")
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r.HandleFunc("/", saveSnapshot).Methods("POST")
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r.PathPrefix("/static/").Handler(http.StripPrefix("/static/", http.FileServer(http.Dir("static/"))))
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http.Handle("/", r)
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fmt.Printf("Listening on port %s...\n", port)
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log.Fatal(http.ListenAndServe(":"+port, nil))
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}
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func showCharts(w http.ResponseWriter, r *http.Request) {
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if countStr := mux.Vars(r)["mins"]; countStr != "" {
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if _, err := strconv.ParseInt(countStr, 10, 0); err != nil {
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http.Redirect(w, r, "/", 303)
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}
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} else {
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http.ServeFile(w, r, "charts.html")
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}
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}
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func sendData(w http.ResponseWriter, r *http.Request) {
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var count int64 = 60
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if vars := mux.Vars(r); vars["mins"] != "" {
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newCount, err := strconv.ParseInt(vars["mins"], 10, 0)
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if err != nil {
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sendInternalError(errors.New("bad snapshot count request"), w, r)
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return
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}
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count = newCount
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}
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records, err := getSnapshotRecordsFromDb(int(count))
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if err != nil {
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sendInternalError(fmt.Errorf("couldn't read rows from the database: %w", err), w, r)
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return
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}
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json, err := createJsonFromSnapshotRecords(records)
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if err != nil {
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sendInternalError(fmt.Errorf("couldn't create a json from the records: %w", err), w, r)
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return
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}
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w.Header().Set("Content-Type", "application/json")
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_, err = fmt.Fprintf(w, string(json))
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if err != nil {
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sendInternalError(err, w, r)
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return
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}
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}
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func saveSnapshot(w http.ResponseWriter, r *http.Request) {
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snapshotSub, err := createSnapshotSubFromJsonBodyStream(r.Body)
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if err != nil {
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sendInternalError(fmt.Errorf("couldn't create snapshot from JSON: %w", err), w, r)
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}
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err = writeSnapshotToDb(snapshotSub)
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if err != nil {
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sendInternalError(fmt.Errorf("couldn't submit snapshot into the database: %w", err), w, r)
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}
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}
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func sendInternalError(err error, w http.ResponseWriter, r *http.Request) {
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errorMessage := "Internal Server Error!"
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if DEBUG {
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errorMessage += fmt.Sprintf(" Happened during %s request for pattern '%s': %s",
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r.Method,
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r.URL,
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err.Error())
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}
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fmt.Println(errorMessage)
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http.Error(w, errorMessage, 500)
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}
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