Add download headers to snapshot take API (#7369)

* Add download headers to snapshot take API

* Add content type

go.mod

@@ -65,7 +65,7 @@ require (
 	github.com/hashicorp/hcl v1.0.0
 	github.com/hashicorp/nomad/api v0.0.0-20190412184103-1c38ced33adf
 	github.com/hashicorp/raft v1.1.1
-	github.com/hashicorp/raft-snapshot v1.0.1
+	github.com/hashicorp/raft-snapshot v1.0.2-0.20190827162939-8117efcc5aab
 	github.com/hashicorp/vault-plugin-auth-alicloud v0.5.2-0.20190814210027-93970f08f2ec
 	github.com/hashicorp/vault-plugin-auth-azure v0.5.2-0.20190814210035-08e00d801115
 	github.com/hashicorp/vault-plugin-auth-centrify v0.5.2-0.20190814210042-090ec2ed93ce

go.sum

@@ -329,6 +329,8 @@ github.com/hashicorp/raft v1.1.1/go.mod h1:vPAJM8Asw6u8LxC3eJCUZmRP/E4QmUGE1R7g7
 github.com/hashicorp/raft-boltdb v0.0.0-20171010151810-6e5ba93211ea/go.mod h1:pNv7Wc3ycL6F5oOWn+tPGo2gWD4a5X+yp/ntwdKLjRk=
 github.com/hashicorp/raft-snapshot v1.0.1 h1:cx002JsTEAfAP0pIuANlDtTXg/pi2Db6YbRRmLQTQKw=
 github.com/hashicorp/raft-snapshot v1.0.1/go.mod h1:5sL9eUn72lH5DzsFIJ9jaysITbHksSSszImWSOTC8Ic=
+github.com/hashicorp/raft-snapshot v1.0.2-0.20190827162939-8117efcc5aab h1:WzGMwlO1DvaC93SvVOBOKtn+nXGEDXapyJuaRV3/VaY=
+github.com/hashicorp/raft-snapshot v1.0.2-0.20190827162939-8117efcc5aab/go.mod h1:5sL9eUn72lH5DzsFIJ9jaysITbHksSSszImWSOTC8Ic=
 github.com/hashicorp/serf v0.8.2 h1:YZ7UKsJv+hKjqGVUUbtE3HNj79Eln2oQ75tniF6iPt0=
 github.com/hashicorp/serf v0.8.2/go.mod h1:6hOLApaqBFA1NXqRQAsxw9QxuDEvNxSQRwA/JwenrHc=
 github.com/hashicorp/vault-plugin-auth-alicloud v0.5.2-0.20190814210027-93970f08f2ec h1:HXVE8h6RXFsPJgwWpE+5CscsgekqtX4nhDlZGV9jEe4=

http/logical.go

@@ -28,7 +28,7 @@ func buildLogicalRequest(core *vault.Core, w http.ResponseWriter, r *http.Reques
 	var data map[string]interface{}
 	var origBody io.ReadCloser
 	var requestReader io.ReadCloser
-	var responseWriter io.Writer
+	var responseWriter http.ResponseWriter
 
 	// Determine the operation
 	var op logical.Operation

physical/raft/raft.go

@@ -21,6 +21,7 @@ import (
 	snapshot "github.com/hashicorp/raft-snapshot"
 	raftboltdb "github.com/hashicorp/vault/physical/raft/logstore"
 	"github.com/hashicorp/vault/sdk/helper/consts"
+	"github.com/hashicorp/vault/sdk/logical"
 	"github.com/hashicorp/vault/vault/cluster"
 	"github.com/hashicorp/vault/vault/seal"
 
@@ -606,7 +607,7 @@ func (b *RaftBackend) Peers(ctx context.Context) ([]Peer, error) {
 // Snapshot takes a raft snapshot, packages it into a archive file and writes it
 // to the provided writer. Seal access is used to encrypt the SHASUM file so we
 // can validate the snapshot was taken using the same master keys or not.
-func (b *RaftBackend) Snapshot(out io.Writer, access seal.Access) error {
+func (b *RaftBackend) Snapshot(out *logical.HTTPResponseWriter, access seal.Access) error {
 	b.l.RLock()
 	defer b.l.RUnlock()
 
@@ -628,6 +629,14 @@ func (b *RaftBackend) Snapshot(out io.Writer, access seal.Access) error {
 	}
 	defer snap.Close()
 
+	size, err := snap.Size()
+	if err != nil {
+		return err
+	}
+
+	out.Header().Add("Content-Disposition", "attachment")
+	out.Header().Add("Content-Length", fmt.Sprintf("%d", size))
+	out.Header().Add("Content-Type", "application/gzip")
 	_, err = io.Copy(out, snap)
 	if err != nil {
 		return err

sdk/logical/response.go

@@ -4,7 +4,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"io"
+	"net/http"
 	"sync/atomic"
 
 	"github.com/hashicorp/vault/sdk/helper/wrapping"
@@ -187,15 +187,15 @@ func RespondWithStatusCode(resp *Response, req *Request, code int) (*Response, e
 // HTTPResponseWriter is optionally added to a request object and can be used to
 // write directly to the HTTP response writter.
 type HTTPResponseWriter struct {
-	writer  io.Writer
+	http.ResponseWriter
 	written *uint32
 }
 
 // NewHTTPResponseWriter creates a new HTTPRepoinseWriter object that wraps the
 // provided io.Writer.
-func NewHTTPResponseWriter(w io.Writer) *HTTPResponseWriter {
+func NewHTTPResponseWriter(w http.ResponseWriter) *HTTPResponseWriter {
 	return &HTTPResponseWriter{
-		writer:  w,
+		ResponseWriter: w,
 		written:        new(uint32),
 	}
 }
@@ -204,7 +204,7 @@ func NewHTTPResponseWriter(w io.Writer) *HTTPResponseWriter {
 func (rw *HTTPResponseWriter) Write(bytes []byte) (int, error) {
 	atomic.StoreUint32(rw.written, 1)
 
-	return rw.writer.Write(bytes)
+	return rw.ResponseWriter.Write(bytes)
 }
 
 // Written tells us if the writer has been written to yet.