Refactor resource discovery

pkg/resource/files.go

@@ -0,0 +1,71 @@
+package resource
+
+import (
+	"bytes"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+func isYAMLFile(info os.FileInfo) bool {
+	return !info.IsDir() && (strings.HasSuffix(strings.ToLower(info.Name()), ".yaml") || strings.HasSuffix(strings.ToLower(info.Name()), ".yml"))
+}
+
+func isJSONFile(info os.FileInfo) bool {
+	return !info.IsDir() && (strings.HasSuffix(strings.ToLower(info.Name()), ".json"))
+}
+
+type DiscoveryError struct {
+	Path string
+	Err  error
+}
+
+func (de DiscoveryError) Error() string {
+	return de.Err.Error()
+}
+
+func FromFiles(paths ...string) (<-chan Resource, <-chan error) {
+	resources := make(chan Resource)
+	errors := make(chan error)
+
+	go func() {
+		for _, path := range paths {
+			// we handle errors in the walk function directly
+			// so it should be safe to discard the outer error
+			_ = filepath.Walk(path, func(p string, i os.FileInfo, err error) error {
+				if err != nil {
+					errors <- DiscoveryError{p, err}
+					return err
+				}
+
+				if !isYAMLFile(i) && !isJSONFile(i) {
+					return nil
+				}
+
+				f, err := os.Open(p)
+				if err != nil {
+					errors <- DiscoveryError{p, err}
+					return err
+				}
+
+				b, err := ioutil.ReadAll(f)
+				if err != nil {
+					errors <- DiscoveryError{p, err}
+					return err
+				}
+
+				for _, r := range bytes.Split(b, []byte("---\n")) {
+					resources <- Resource{Path: p, Bytes: r}
+				}
+
+				return nil
+			})
+		}
+
+		close(resources)
+		close(errors)
+	}()
+
+	return resources, errors
+}