102 lines
1.8 KiB
Go
102 lines
1.8 KiB
Go
package main
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import (
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"encoding/csv"
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"encoding/json"
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"log"
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"net/http"
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"os"
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"path/filepath"
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"strconv"
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"time"
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)
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type Summary struct {
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StartMS float64 `json:"start_ms"`
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EndMS float64 `json:"end_ms"`
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Values []float64 `json:"values"` // [max, mean+std, mean, mean-std, min]
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}
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var (
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dataFile *os.File
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writer *csv.Writer
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)
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func initDataFile() {
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_ = os.MkdirAll("data", 0755)
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filename := filepath.Join(
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"data",
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time.Now().Format("summary_20060102_150405.csv"),
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)
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f, err := os.OpenFile(filename,
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os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0644)
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if err != nil {
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log.Fatal(err)
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}
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dataFile = f
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writer = csv.NewWriter(dataFile)
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// header for plotting
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writer.Write([]string{
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"start_ms",
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"end_ms",
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"max",
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"mean_plus_std",
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"mean",
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"mean_minus_std",
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"min",
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})
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writer.Flush()
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}
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func handler(w http.ResponseWriter, r *http.Request) {
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if r.Method != http.MethodPost {
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http.Error(w, "POST only", http.StatusMethodNotAllowed)
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return
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}
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var s Summary
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if err := json.NewDecoder(r.Body).Decode(&s); err != nil {
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http.Error(w, "invalid JSON", http.StatusBadRequest)
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return
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}
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if len(s.Values) != 5 {
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http.Error(w, "need 5 values", http.StatusBadRequest)
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return
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}
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row := []string{
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formatFloat(s.StartMS),
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formatFloat(s.EndMS),
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formatFloat(s.Values[0]),
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formatFloat(s.Values[1]),
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formatFloat(s.Values[2]),
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formatFloat(s.Values[3]),
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formatFloat(s.Values[4]),
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}
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writer.Write(row)
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writer.Flush()
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log.Println("Summary appended")
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w.WriteHeader(http.StatusOK)
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w.Write([]byte("ok"))
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}
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func formatFloat(v float64) string {
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return strconv.FormatFloat(v, 'f', 6, 64)
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}
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func main() {
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initDataFile()
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defer dataFile.Close()
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http.HandleFunc("/data", handler)
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log.Println("Listening on :8080")
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log.Fatal(http.ListenAndServe(":8080", nil))
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}
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