The ctxio package gives golang io.copy operations the ability to terminate with context and retrieve progress data.

  go get github.com/binalyze/ctxio

Here is an example to use ctxio with io.copy operation. You can find more examples in test files.

srcFile, err := os.Open("sourcefile.log")
dstFile, err := os.Create("destinationFile.log")

progressFn := func(n int64) {
    // Here you can send progress to API etc.
}

w := NewWriter(ctx, dstFile, progressFn)

written, err := io.Copy(w, file)

• Add io.Reader support just like io.Writer

• context-aware-ioreader-for-golang-by-mat-ryer Context-aware io.Reader for Go.
• github.com/jbenet/go-context/io Context-aware reader and writer.
• github.com/northbright/ctx/ctxcopy Context-aware io.Copy.
• gitlab.com/streamy/concon Context-aware net.Conn.