diff --git a/Makefile b/Makefile
index b2069c6..e250819 100644
--- a/Makefile
+++ b/Makefile
@@ -15,7 +15,3 @@ test: ## Run tests only
 test-coverage: ## Run tests and show coverage in browser
 	go test -v -coverprofile=$(COVERAGE) -covermode=count
 	go tool cover -html=$(COVERAGE)
-
-install: ## Install packages for dependencies
-	go get github.com/Masterminds/glide
-	glide install
diff --git a/circle.yml b/circle.yml
index 4adcf94..f976a80 100644
--- a/circle.yml
+++ b/circle.yml
@@ -11,8 +11,6 @@ dependencies:
     - go get github.com/jstemmer/go-junit-report
     - mkdir -p $REPO_PATH
     - rsync -azC --delete ./ $REPO_PATH/
-  override:
-    - cd $REPO_PATH && make install
 
 test:
   override:
diff --git a/digestRequest.go b/digestRequest.go
index de00615..63e2cb7 100644
--- a/digestRequest.go
+++ b/digestRequest.go
@@ -9,7 +9,6 @@ import (
 	"strings"
 
 	"github.com/delphinus/random-string"
-	"github.com/pkg/errors"
 	"golang.org/x/net/context"
 )
 
@@ -70,7 +69,7 @@ func New(ctx context.Context, username, password string) *DigestRequest {
 func (r *DigestRequest) Do(req *http.Request) (*http.Response, error) {
 	parts, err := r.makeParts(req)
 	if err != nil {
-		return nil, errors.WithStack(err)
+		return nil, err
 	}
 
 	if parts != nil {
@@ -84,7 +83,7 @@ func (r *DigestRequest) makeParts(req *http.Request) (map[string]string, error)
 	authReq, err := http.NewRequest(req.Method, req.URL.String(), nil)
 	resp, err := r.client.Do(authReq)
 	if err != nil {
-		return nil, errors.WithStack(err)
+		return nil, err
 	}
 	defer func() { _ = resp.Body.Close() }()
 
@@ -93,7 +92,7 @@ func (r *DigestRequest) makeParts(req *http.Request) (map[string]string, error)
 	}
 
 	if len(resp.Header[wwwAuthenticate]) == 0 {
-		return nil, errors.Errorf("headers do not have %s", wwwAuthenticate)
+		return nil, fmt.Errorf("headers do not have %s", wwwAuthenticate)
 	}
 
 	headers := strings.Split(resp.Header[wwwAuthenticate][0], ",")
@@ -107,7 +106,7 @@ func (r *DigestRequest) makeParts(req *http.Request) (map[string]string, error)
 	}
 
 	if len(parts) != len(wanted) {
-		return nil, errors.Errorf("header is invalid: %+v", parts)
+		return nil, fmt.Errorf("header is invalid: %+v", parts)
 	}
 
 	return parts, nil
diff --git a/glide.lock b/glide.lock
deleted file mode 100644
index b547bd2..0000000
--- a/glide.lock
+++ /dev/null
@@ -1,19 +0,0 @@
-hash: b6f4052702876c99020bbfbc9faf6838976254b53627483a132265b54cf040a7
-updated: 2017-05-20T14:46:18.013330986+09:00
-imports:
-- name: github.com/delphinus/random-string
-  version: 3a848976dd952cb4263f7aa61a6886d16014151b
-- name: github.com/pkg/errors
-  version: 645ef00459ed84a119197bfb8d8205042c6df63d
-- name: golang.org/x/net
-  version: da118f7b8e5954f39d0d2130ab35d4bf0e3cb344
-  subpackages:
-  - context
-testImports:
-- name: github.com/abbot/go-http-auth
-  version: d45c47bedec736d172957bd394786b76626fa8ac
-- name: golang.org/x/crypto
-  version: c7af5bf2638a1164f2eb5467c39c6cffbd13a02e
-  subpackages:
-  - bcrypt
-  - blowfish
diff --git a/glide.yaml b/glide.yaml
deleted file mode 100644
index ea71973..0000000
--- a/glide.yaml
+++ /dev/null
@@ -1,11 +0,0 @@
-package: github.com/delphinus/go-digest-request
-import:
-- package: github.com/delphinus/random-string
-- package: github.com/pkg/errors
-  version: ^0.8.0
-- package: golang.org/x/net
-  subpackages:
-  - context
-testImport:
-- package: github.com/abbot/go-http-auth
-  version: d45c47bedec736d172957bd394786b76626fa8ac