feat(alerting): add support for uploading images to webdav.

closes #5770

pkg/components/imguploader/s3uploader.go

@@ -0,0 +1,53 @@
+package imguploader
+
+import (
+	"io/ioutil"
+	"net/http"
+
+	"github.com/grafana/grafana/pkg/util"
+	"github.com/kr/s3/s3util"
+)
+
+type S3Uploader struct {
+	bucket    string
+	secretKey string
+	accessKey string
+}
+
+func NewS3Uploader(bucket, accessKey, secretKey string) *S3Uploader {
+	return &S3Uploader{
+		bucket:    bucket,
+		accessKey: accessKey,
+		secretKey: secretKey,
+	}
+}
+
+func (u *S3Uploader) Upload(path string) (string, error) {
+
+	s3util.DefaultConfig.AccessKey = u.accessKey
+	s3util.DefaultConfig.SecretKey = u.secretKey
+
+	header := make(http.Header)
+	header.Add("x-amz-acl", "public-read")
+	header.Add("Content-Type", "image/png")
+
+	fullUrl := u.bucket + util.GetRandomString(20) + ".png"
+	writer, err := s3util.Create(fullUrl, header, nil)
+	if err != nil {
+		return "", err
+	}
+
+	defer writer.Close()
+
+	imgData, err := ioutil.ReadFile(path)
+	if err != nil {
+		return "", err
+	}
+
+	_, err = writer.Write(imgData)
+	if err != nil {
+		return "", err
+	}
+
+	return fullUrl, nil
+}