refactor: drop hashstructure dependency (#223)

* refactor: drop hashstructure dependency

hashstructure was archived and it is no longer maintained
we are only using the library to hash a slice of strings,
implement the logic in a custom method and drop the library

* lint: update notice

* test: verify custom hash function is equivalent to hashstructure lib

Author: kruskall

NOTICE.txt

@@ -795,37 +795,6 @@ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
 
 
---------------------------------------------------------------------------------
-Dependency : github.com/mitchellh/hashstructure
-Version: v1.1.0
-Licence type (autodetected): MIT
---------------------------------------------------------------------------------
-
-Contents of probable licence file $GOMODCACHE/github.com/mitchellh/[email protected]/LICENSE:
-
-The MIT License (MIT)
-
-Copyright (c) 2016 Mitchell Hashimoto
-
-Permission is hereby granted, free of charge, to any person obtaining a copy
-of this software and associated documentation files (the "Software"), to deal
-in the Software without restriction, including without limitation the rights
-to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-copies of the Software, and to permit persons to whom the Software is
-furnished to do so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in
-all copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-THE SOFTWARE.
-
-
 --------------------------------------------------------------------------------
 Dependency : github.com/rcrowley/go-metrics
 Version: v0.0.0-20201227073835-cf1acfcdf475

filewatcher/filewatcher.go

@@ -18,11 +18,11 @@
 package filewatcher
 
 import (
+	"encoding/binary"
+	"hash/fnv"
 	"os"
 	"time"
 
-	"github.com/mitchellh/hashstructure"
-
 	"github.com/elastic/elastic-agent-libs/logp"
 )
 
@@ -77,7 +77,7 @@ func (f *FileWatcher) Scan() ([]string, bool, error) {
 		files = append(files, path)
 	}
 
-	hash, err := hashstructure.Hash(files, nil)
+	hash, err := hash(files)
 	if err != nil {
 		return files, true, err
 	}
@@ -90,3 +90,28 @@ func (f *FileWatcher) Scan() ([]string, bool, error) {
 
 	return files, true, nil
 }
+
+func hash(files []string) (uint64, error) {
+	var u uint64
+
+	for _, f := range files {
+		current := hashString(f)
+
+		h := fnv.New64()
+		if err := binary.Write(h, binary.LittleEndian, u); err != nil {
+			return 0, err
+		}
+		if err := binary.Write(h, binary.LittleEndian, current); err != nil {
+			return 0, err
+		}
+		u = h.Sum64()
+	}
+
+	return u, nil
+}
+
+func hashString(s string) uint64 {
+	h := fnv.New64()
+	h.Write([]byte(s))
+	return h.Sum64()
+}

filewatcher/filewatcher_test.go

@@ -78,3 +78,11 @@ func TestFileWatcher(t *testing.T) {
 	assert.NoError(t, err)
 	assert.True(t, changed, "'changed' must be true, one file has been removed")
 }
+
+func TestHash(t *testing.T) {
+	files := []string{"file-1", "file-2", "file-3"}
+	i, err := hash(files)
+	assert.NoError(t, err)
+	// ensure custom hash function returns the same result as deprecated hashstructure lib
+	assert.Equal(t, uint64(11400963159482616226), i)
+}

go.mod

@@ -11,7 +11,6 @@ require (
 	github.com/gofrs/uuid/v5 v5.2.0
 	github.com/magefile/mage v1.13.0
 	github.com/mattn/go-colorable v0.1.12
-	github.com/mitchellh/hashstructure v1.1.0
 	github.com/rcrowley/go-metrics v0.0.0-20201227073835-cf1acfcdf475
 	github.com/spf13/cobra v1.7.0
 	github.com/stretchr/testify v1.9.0

go.sum

@@ -51,8 +51,6 @@ github.com/mattn/go-colorable v0.1.12/go.mod h1:u5H1YNBxpqRaxsYJYSkiCWKzEfiAb1Gb
 github.com/mattn/go-isatty v0.0.12/go.mod h1:cbi8OIDigv2wuxKPP5vlRcQ1OAZbq2CE4Kysco4FUpU=
 github.com/mattn/go-isatty v0.0.14 h1:yVuAays6BHfxijgZPzw+3Zlu5yQgKGP2/hcQbHb7S9Y=
 github.com/mattn/go-isatty v0.0.14/go.mod h1:7GGIvUiUoEMVVmxf/4nioHXj79iQHKdU27kJ6hsGG94=
-github.com/mitchellh/hashstructure v1.1.0 h1:P6P1hdjqAAknpY/M1CGipelZgp+4y9ja9kmUZPXP+H0=
-github.com/mitchellh/hashstructure v1.1.0/go.mod h1:xUDAozZz0Wmdiufv0uyhnHkUTN6/6d8ulp4AwfLKrmA=
 github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e h1:fD57ERR4JtEqsWbfPhv4DMiApHyliiK5xCTNVSPiaAs=
 github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e/go.mod h1:zD1mROLANZcx1PVRCS0qkT7pwLkGfwJo4zjcN/Tysno=
 github.com/pkg/errors v0.8.0/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=