71 lines
1.5 KiB
Go
71 lines
1.5 KiB
Go
package main
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import (
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"database/sql"
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"fmt"
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"log"
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"net/http"
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"os"
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_ "github.com/lib/pq"
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)
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var db *sql.DB
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func getenv(key, fallback string) string {
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if v := os.Getenv(key); v != "" {
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return v
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}
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return fallback
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}
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func initDB() {
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dsn := fmt.Sprintf(
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"host=%s dbname=%s user=%s password=%s sslmode=disable",
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getenv("DB_HOST", "db"),
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getenv("DB_NAME", "visitcount"),
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getenv("DB_USER", "app"),
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getenv("DB_PASSWORD", "secret"),
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)
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var err error
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db, err = sql.Open("postgres", dsn)
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if err != nil {
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log.Fatal(err)
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}
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if err = db.Ping(); err != nil {
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log.Fatal(err)
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}
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_, err = db.Exec(
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`CREATE TABLE IF NOT EXISTS visits (count INTEGER DEFAULT 0);` +
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`INSERT INTO visits SELECT 0 WHERE NOT EXISTS (SELECT 1 FROM visits);`,
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)
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if err != nil {
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log.Fatal(err)
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}
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}
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func handleIndex(w http.ResponseWriter, r *http.Request) {
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var count int
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err := db.QueryRow("UPDATE visits SET count = count + 1 RETURNING count").Scan(&count)
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if err != nil {
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http.Error(w, "database error", http.StatusInternalServerError)
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return
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}
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fmt.Fprintf(w, "<h1>VisitCounter</h1><p>Visited <strong>%d</strong> times.</p>", count)
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}
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func handleHealth(w http.ResponseWriter, r *http.Request) {
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if err := db.Ping(); err != nil {
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http.Error(w, "db unreachable", http.StatusServiceUnavailable)
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return
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}
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fmt.Fprintln(w, "ok")
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}
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func main() {
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initDB()
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http.HandleFunc("/", handleIndex)
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http.HandleFunc("/health", handleHealth)
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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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