init: basic tools

output_csv.go

@@ -0,0 +1,71 @@
+package script
+
+import (
+	"context"
+	"encoding/csv"
+	"errors"
+	"os"
+)
+
+// CSV creates csv.Writer writing to underlying file.
+// Do not forget to call Close method once you are done.
+func NewCSVWriter(filename string) (*CSVWriter, error) {
+	return newCSVwriter(filename)
+}
+
+type CSVWriter struct {
+	f   *os.File
+	wr  *csv.Writer
+	err error
+}
+
+// Write writer row to csv. Writes are buffered
+func (c *CSVWriter) Write(_ context.Context, record []string) error {
+	err := c.wr.Write(record)
+	c.err = err
+
+	return err
+}
+
+// Close flushes underlying csv.Writer and closes
+// file.
+func (c *CSVWriter) Close() error {
+	c.wr.Flush()
+	flushErr := c.wr.Error()
+	closeErr := c.f.Close()
+
+	err := errors.Join(flushErr, closeErr)
+	c.err = err
+
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// Error return last encountered error.
+func (c *CSVWriter) Error() error {
+	return c.err
+}
+
+func newCSVwriter(name string) (*CSVWriter, error) {
+	var (
+		f   *os.File
+		err error
+	)
+
+	if _, err = os.Stat(name); err == nil {
+		f, err = os.OpenFile(name, os.O_APPEND|os.O_WRONLY, 0664)
+	} else {
+		f, err = os.Create(name)
+	}
+
+	if err != nil {
+		return nil, err
+	}
+
+	csvwr := csv.NewWriter(f)
+
+	return &CSVWriter{f: f, wr: csvwr}, nil
+}