move: log parsers

logparser/v5/pipe/pipeline.go

@@ -0,0 +1,48 @@
+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package pipe
+
+import (
+	"fmt"
+	"os"
+)
+
+// Pipeline takes records from a source, transforms, and sends them to a destionation.
+type Pipeline struct {
+	src   Iterator
+	trans []Transform
+	dst   Digester
+}
+
+// New creates a new pipeline.
+func New(src Iterator, dst Digester, t ...Transform) *Pipeline {
+	return &Pipeline{
+		src:   &logCount{Iterator: src},
+		dst:   dst,
+		trans: t,
+	}
+}
+
+// Run the pipeline.
+func (p *Pipeline) Run() error {
+	defer func() {
+		n := p.src.(*logCount).count()
+		fmt.Fprintf(os.Stderr, "%d records processed.\n", n)
+	}()
+
+	last := p.src
+
+	for _, t := range p.trans {
+		if err := t.Digest(last); err != nil {
+			return err
+		}
+		last = t
+	}
+
+	return p.dst.Digest(last)
+}