Imports github.com/Sirupsen/logrus github.com/franela/goreq github.com/skygeario/skygear-server/pkg/server/logging gopkg.in/amz.v3/aws gopkg.in/amz.v3/s3 Standard library imports bytes crypto/hmac crypto/sha256 encoding/base64 errors fmt io io/ioutil net/http net/url os path/filepath strconv strings sync time