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transport.go
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transport.go
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// SPDX-FileCopyrightText: 2021 Comcast Cable Communications Management, LLC
// SPDX-License-Identifier: Apache-2.0
package store
import (
"context"
"crypto/sha256"
"encoding/json"
"errors"
"fmt"
"io"
"net/http"
"regexp"
"sort"
"time"
kithttp "github.com/go-kit/kit/transport/http"
"github.com/gorilla/mux"
"github.com/xmidt-org/argus/auth"
"github.com/xmidt-org/argus/model"
"github.com/xmidt-org/bascule"
"go.uber.org/zap"
)
// request URL path keys.
const (
bucketVarKey = "bucket"
idVarKey = "id"
)
// Request and Response Headers.
const (
ItemOwnerHeaderKey = "X-Xmidt-Owner"
XmidtErrorHeaderKey = "X-Xmidt-Error"
)
// ElevatedAccessLevel is the bascule attribute value found in requests that should be granted
// priviledged access to operations.
const ElevatedAccessLevel = 1
// ErrCasting indicates there was (most likely) a middleware wiring mistake with
// the go-kit style encoders/decoders.
var ErrCasting = errors.New("casting error due to middleware wiring mistake")
var (
errBodyReadFailure = BadRequestErr{Message: "Failed to read body."}
errPayloadUnmarshalFailure = BadRequestErr{Message: "Failed to unmarshal json payload."}
)
type transportConfig struct {
AccessLevelAttributeKey string
ItemMaxTTL time.Duration
IDFormatRegex *regexp.Regexp
BucketFormatRegex *regexp.Regexp
OwnerFormatRegex *regexp.Regexp
ItemDataMaxDepth uint
}
type getOrDeleteItemRequest struct {
key model.Key
owner string
adminMode bool
}
type getAllItemsRequest struct {
bucket string
owner string
adminMode bool
}
type setItemRequest struct {
key model.Key
item OwnableItem
adminMode bool
}
type setItemResponse struct {
existingResource bool
}
func getAllItemsRequestDecoder(config *transportConfig) kithttp.DecodeRequestFunc {
return func(ctx context.Context, r *http.Request) (interface{}, error) {
var (
bucket = mux.Vars(r)[bucketVarKey]
owner = r.Header.Get(ItemOwnerHeaderKey)
)
if !isBucketValid(config.BucketFormatRegex, bucket) {
return nil, errInvalidBucket
}
if !isOwnerValid(config.OwnerFormatRegex, owner) {
return nil, errInvalidOwner
}
return &getAllItemsRequest{
bucket: bucket,
owner: owner,
adminMode: hasElevatedAccess(ctx, config.AccessLevelAttributeKey),
}, nil
}
}
func setItemRequestDecoder(config *transportConfig) kithttp.DecodeRequestFunc {
return func(ctx context.Context, r *http.Request) (interface{}, error) {
var (
URLVars = mux.Vars(r)
id = URLVars[idVarKey]
bucket = URLVars[bucketVarKey]
owner = r.Header.Get(ItemOwnerHeaderKey)
)
if err := validateItemRequestVars(config, owner, bucket, id); err != nil {
return nil, err
}
data, err := io.ReadAll(r.Body)
if err != nil {
return nil, fmt.Errorf("%w: %v", errBodyReadFailure, err)
}
unmarshaler := validItemUnmarshaler{config: config, id: id}
if err := json.Unmarshal(data, &unmarshaler); err != nil {
var berr BadRequestErr
if ok := errors.As(err, &berr); !ok {
err = fmt.Errorf("%w: %v", errPayloadUnmarshalFailure, err)
}
return nil, err
}
return &setItemRequest{
item: OwnableItem{
Item: unmarshaler.item,
Owner: owner,
},
key: model.Key{
Bucket: bucket,
ID: id,
},
adminMode: hasElevatedAccess(ctx, config.AccessLevelAttributeKey),
}, nil
}
}
func getOrDeleteItemRequestDecoder(config *transportConfig) kithttp.DecodeRequestFunc {
return func(ctx context.Context, r *http.Request) (interface{}, error) {
var (
URLVars = mux.Vars(r)
id = URLVars[idVarKey]
bucket = URLVars[bucketVarKey]
owner = r.Header.Get(ItemOwnerHeaderKey)
)
if err := validateItemRequestVars(config, owner, bucket, id); err != nil {
return nil, err
}
return &getOrDeleteItemRequest{
key: model.Key{
Bucket: bucket,
ID: id,
},
adminMode: hasElevatedAccess(ctx, config.AccessLevelAttributeKey),
owner: r.Header.Get(ItemOwnerHeaderKey),
}, nil
}
}
func encodeSetItemResponse(ctx context.Context, rw http.ResponseWriter, response interface{}) error {
r := response.(*setItemResponse)
if r.existingResource {
rw.WriteHeader(http.StatusOK)
} else {
rw.WriteHeader(http.StatusCreated)
}
return nil
}
// TODO: I noticed order of result elements get shuffled around on multiple fetches
// This is because of dynamodb. To make tests easier, results are sorted by lexicographical non-decreasing
// order of the ids.
func encodeGetAllItemsResponse(ctx context.Context, rw http.ResponseWriter, response interface{}) error {
items := response.(map[string]OwnableItem)
list := []model.Item{}
for _, value := range items {
list = append(list, value.Item)
}
sort.SliceStable(list, func(i, j int) bool {
return list[i].ID < list[j].ID
})
data, err := json.Marshal(&list)
if err != nil {
return err
}
rw.Header().Add("Content-Type", "application/json")
rw.Write(data)
return nil
}
func encodeGetOrDeleteItemResponse(ctx context.Context, rw http.ResponseWriter, response interface{}) error {
item := response.(*OwnableItem)
data, err := json.Marshal(&item.Item)
if err != nil {
return err
}
rw.Header().Add("Content-Type", "application/json")
rw.Write(data)
return nil
}
func transferHeaders(w http.ResponseWriter, h http.Header) {
for k, values := range h {
for _, v := range values {
w.Header().Add(k, v)
}
}
}
func encodeError(getLogger func(context.Context) *zap.Logger) kithttp.ErrorEncoder {
return func(ctx context.Context, err error, w http.ResponseWriter) {
var headerer kithttp.Headerer
if errors.As(err, &headerer) {
transferHeaders(w, headerer.Headers())
}
var sErrorer sanitizedErrorer
if errors.As(err, &sErrorer) {
w.Header().Set(XmidtErrorHeaderKey, sErrorer.SanitizedError())
}
code := http.StatusInternalServerError
var statusCoder kithttp.StatusCoder
if errors.As(err, &statusCoder) {
code = statusCoder.StatusCode()
}
logger := getLogger(ctx)
if logger != nil && code != http.StatusNotFound {
logger.Error("sending non-200, non-404 response", zap.Error(err), zap.Int("code", code))
}
w.WriteHeader(code)
}
}
// Sha256HexDigest returns the SHA-256 hex digest of the given input.
func Sha256HexDigest(message string) string {
return fmt.Sprintf("%x", sha256.Sum256([]byte(message)))
}
func hasElevatedAccess(ctx context.Context, accessLevelAttributeKey string) bool {
basculeAuth, ok := bascule.FromContext(ctx)
if !ok {
return false
}
attributes := basculeAuth.Token.Attributes()
attribute, ok := attributes.Get(accessLevelAttributeKey)
if !ok {
return false
}
accessLevel, ok := attribute.(int)
if !ok {
return false
}
return accessLevel == auth.ElevatedAccessLevelAttributeValue
}