README
¶
diagio
The Go package diagio implements I/O wrappers which can be useful for debugging and other diagnostics purposes.
CounterReader implements an io.Reader which keeps track of bytes read from it.
CounterWriter implements an io.Writer which keeps track of bytes written to it.
DiagReader implements an io.Reader which produces diagnostics output (number of bytes, current position, error, hex dump of data) whenever it is read from.
DiagWriter implements an io.Writer which produces diagnostics output (number of bytes, current position, error, hex dump of data) whenever it is written to.
Documentation:
https://pkg.go.dev/github.com/snabb/diagio
Simple example:
cw := diagio.NewCounterWriter(os.Stdout)
fmt.Fprintln(cw, "hello world")
fmt.Println(cw.Count())
// Output:
// hello world
// 12
The Git repository is located at: https://github.com/snabb/diagio
License
MIT
Documentation
¶
Overview ¶
Package diagio implements I/O wrappers which can be useful for debugging and other diagnostics purposes.
Index ¶
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func Count ¶
Count takes anything and calls Count() on it and returns the result.
Returns -1 if Count() method does not exist.
This is useful for passing around an ordinary io.Reader or an ordinary io.Writer and later calling Count() on it.
Example ¶
package main
import (
"fmt"
"io"
"os"
"github.com/snabb/diagio"
)
func main() {
cw := diagio.NewCounterWriter(os.Stdout)
f := func(w io.Writer) {
fmt.Fprintln(w, "foobar")
fmt.Println(diagio.Count(w))
}
f(cw)
}
Output: foobar 7
Types ¶
type CounterReader ¶
type CounterReader struct {
// contains filtered or unexported fields
}
CounterReader implements io.Reader. Number of bytes read is tracked.
Example ¶
package main
import (
"bytes"
"fmt"
"io"
"github.com/snabb/diagio"
)
func main() {
input1 := bytes.NewBufferString("hello world")
input2 := diagio.NewCounterReader(input1)
io.Copy(io.Discard, input2)
fmt.Println(input2.Count())
}
Output: 11
func NewCounterReader ¶
func NewCounterReader(r io.Reader) (cr *CounterReader)
NewCounterReader wraps io.Reader and returns CounterReader.
func (*CounterReader) Count ¶
func (cr *CounterReader) Count() (n int64)
Count returns the number of bytes read from the CounterReader.
type CounterWriter ¶
type CounterWriter struct {
// contains filtered or unexported fields
}
CounterWriter implements io.Writer. Number of bytes written is tracked.
Example ¶
package main
import (
"fmt"
"os"
"github.com/snabb/diagio"
)
func main() {
cw := diagio.NewCounterWriter(os.Stdout)
fmt.Fprintln(cw, "hello world")
fmt.Println(cw.Count())
}
Output: hello world 12
func NewCounterWriter ¶
func NewCounterWriter(w io.Writer) (cw *CounterWriter)
NewCounterWriter wraps io.Writer and returns CounterWriter.
func (*CounterWriter) Count ¶
func (cw *CounterWriter) Count() (n int64)
Count returns the number of bytes written to the CounterWriter.
type DiagReader ¶
type DiagReader struct {
// contains filtered or unexported fields
}
DiagReader implements io.Reader. Diagnostics output is produced whenever it is read from.
Example ¶
package main
import (
"bytes"
"io"
"os"
"github.com/snabb/diagio"
)
func main() {
input1 := bytes.NewBufferString("hello world")
input2 := diagio.NewDiagReader(input1, os.Stdout)
io.Copy(io.Discard, input2)
}
Output: >>> Read 8192 bytes at 0 (start) === 00000000 68 65 6c 6c 6f 20 77 6f 72 6c 64 |hello world| <<< Read 11 bytes (err = <nil>) (end) === >>> Read 8192 bytes at 11 (start) === <<< Read 0 bytes (err = EOF) (end) ===
func NewDiagReader ¶
func NewDiagReader(r io.Reader, diagOutput io.Writer) (dr *DiagReader)
NewDiagReader wraps io.Reader and returns DiagReader.
func (*DiagReader) PrintHex ¶
func (dr *DiagReader) PrintHex(v bool)
PrintHex enables or disables hex dump output. The default is enabled.
func (*DiagReader) PrintInfo ¶
func (dr *DiagReader) PrintInfo(v bool)
PrintInfo enables or disables output of number of bytes read, stream position and possible error code. The default is enabled.
type DiagWriter ¶
type DiagWriter struct {
// contains filtered or unexported fields
}
DiagWriter implements io.Writer. Diagnostics output is produced whenever it is written to.
Example ¶
package main
import (
"fmt"
"io"
"os"
"github.com/snabb/diagio"
)
func main() {
output := diagio.NewDiagWriter(io.Discard, os.Stdout)
fmt.Fprint(output, "hello world")
}
Output: >>> Write 11 bytes at 0 (start) === 00000000 68 65 6c 6c 6f 20 77 6f 72 6c 64 |hello world| <<< Wrote 11 bytes (err = <nil>) (end) ===
func NewDiagWriter ¶
func NewDiagWriter(w io.Writer, diagOutput io.Writer) (dw *DiagWriter)
NewDiagWriter wraps io.Writer and returns DiagWriter.
func (*DiagWriter) PrintHex ¶
func (dw *DiagWriter) PrintHex(v bool)
PrintHex enables or disables hex dump output. The default is enabled.
func (*DiagWriter) PrintInfo ¶
func (dw *DiagWriter) PrintInfo(v bool)
PrintInfo enables or disables output of number of bytes written, stream position and possible error code. The default is enabled.
Source Files