I'm having an issue with writing lines to a csv file while iterating over a channel. I'm new to Go, but the syntax for file IO looks synchronous to me. Given that I would expect that a write operation returning successfully would indicate that the write is complete, but that's not what I'm observing. This is essentially what I have going on in my application:
package main
import (
"encoding/csv"
"log"
"os"
)
func main() {
file, err := os.Create("test.csv")
if err != nil {
log.Fatalf("Error opening file: %s", err.Error())
}
defer file.Close()
writer := csv.NewWriter(file)
channel := make(chan []string)
counter := 0
go func() {
defer close(channel)
for i := 0; i < 100; i++ {
channel <- []string{"col1", "col2"}
}
}()
for vals := range channel {
if err := writer.Write(vals); err != nil {
log.Fatalf("Error writing to csv: %s", err.Error())
}
counter++
}
log.Printf("%d lines written", counter)
}
There's a go routine passing values through a channel, and I'm iterating over those values and writing them to a CSV file. I get no errors, and at the end it logs that 100 lines have been written.
When I check the CSV file though it's empty. The behavior I'm seeing in my application is the file is written incompletely; it'll stop halfway through writing a record. I'm sure I'm missing something, but if the write returns with no errors why is there nothing in the file?
