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January 1, 2019 16:38
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HTTP DB Context
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package main | |
import ( | |
"context" | |
"database/sql" | |
"log" | |
"net/http" | |
_ "github.com/lib/pq" | |
) | |
var db *sql.DB | |
func usersNoCtx() { | |
txn, err := db.Begin() | |
if err != nil { | |
log.Fatal(err) | |
} | |
log.Println("In txn") | |
if _, err := txn.Exec("SELECT pg_sleep(5)"); err != nil { | |
log.Println("SELECT error:", err) | |
} | |
if err := txn.Commit(); err != nil { | |
log.Fatal(err) | |
} | |
log.Println("Committed") | |
} | |
func users(ctx context.Context) { | |
txn, err := db.BeginTx(ctx, &sql.TxOptions{ReadOnly: true}) | |
if err != nil { | |
log.Fatal(err) | |
} | |
log.Println("In txn") | |
if _, err := txn.ExecContext(ctx, "SELECT pg_sleep(5)"); err != nil { | |
log.Println("SELECT error:", err) | |
} | |
if ctx.Err() != nil { | |
log.Println("Context cancelled:", ctx.Err()) | |
return | |
} | |
if err := txn.Commit(); err != nil { | |
log.Fatal(err) | |
} | |
log.Println("Committed") | |
} | |
func handler(w http.ResponseWriter, r *http.Request) { | |
ctx := r.Context() | |
users(ctx) | |
w.Write([]byte("OK\n")) | |
} | |
func main() { | |
var err error | |
db, err = sql.Open("postgres", "dbname=webthing sslmode=disable") | |
if err != nil { | |
panic(err) | |
} | |
if err := db.Ping(); err != nil { | |
log.Fatal(err) | |
} | |
http.HandleFunc("/", handler) | |
log.Fatal(http.ListenAndServe("localhost:8088", nil)) | |
} |
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log_min_messages = info | |
log_connections = on | |
log_disconnections = on | |
log_duration = on | |
log_line_prefix = '[%m] %u@%d ' | |
log_statement = 'all' |
Author
jamesog
commented
Jan 1, 2019
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