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imageproxy/internal/s3cache/s3cache.go
Will Norris 0ee5167444 switch to official AWS Go SDK
This uses the official Go SDK from Amazon, which supports the newer v4
authentication method.  Fixes #74.  Doing so also required adding a new
s3cache package which uses the official SDK.

THIS IS A BREAKING CHANGE for anyone that uses s3, since the syntax of
the command line flag is now different.  This is unfortunately necessary
because aws-sdk-go always requires the region to be explicitly declared,
which wasn't always the case with the previous format.  This breaking
change is unfortunate, but given that the other s3 package hasn't seen
updates in years, and so many new S3 regions only support the newer v4
authentication method, it's necessary.
2017-09-12 04:44:43 +00:00

110 lines
2.4 KiB
Go

// Package s3cache provides an httpcache.Cache implementation that stores
// cached values on Amazon S3.
package s3cache
import (
"bytes"
"crypto/md5"
"encoding/hex"
"io"
"io/ioutil"
"log"
"net/url"
"path"
"strings"
"github.com/aws/aws-sdk-go/aws"
"github.com/aws/aws-sdk-go/aws/awserr"
"github.com/aws/aws-sdk-go/aws/session"
"github.com/aws/aws-sdk-go/service/s3"
)
type cache struct {
*s3.S3
bucket, prefix string
}
func (c *cache) Get(key string) ([]byte, bool) {
key = path.Join(c.prefix, keyToFilename(key))
input := &s3.GetObjectInput{
Bucket: &c.bucket,
Key: &key,
}
resp, err := c.GetObject(input)
if err != nil {
if aerr, ok := err.(awserr.Error); ok && aerr.Code() != "NoSuchKey" {
log.Printf("error fetching from s3: %v", aerr)
}
return nil, false
}
value, err := ioutil.ReadAll(resp.Body)
if err != nil {
log.Printf("error reading s3 response body: %v", err)
return nil, false
}
return value, true
}
func (c *cache) Set(key string, value []byte) {
key = path.Join(c.prefix, keyToFilename(key))
input := &s3.PutObjectInput{
Body: aws.ReadSeekCloser(bytes.NewReader(value)),
Bucket: &c.bucket,
Key: &key,
}
_, err := c.PutObject(input)
if err != nil {
log.Printf("error writing to s3: %v", err)
}
}
func (c *cache) Delete(key string) {
key = path.Join(c.prefix, keyToFilename(key))
input := &s3.DeleteObjectInput{
Bucket: &c.bucket,
Key: &key,
}
_, err := c.DeleteObject(input)
if err != nil {
log.Printf("error deleting from s3: %v", err)
}
}
func keyToFilename(key string) string {
h := md5.New()
io.WriteString(h, key)
return hex.EncodeToString(h.Sum(nil))
}
// New constructs a cache configured using the provided URL string. URL should
// be of the form: "s3://region/bucket/optional-path-prefix". Credentials
// should be specified using one of the mechanisms supported by aws-sdk-go (see
// https://docs.aws.amazon.com/sdk-for-go/api/aws/session/).
func New(s string) (*cache, error) {
u, err := url.Parse(s)
if err != nil {
return nil, err
}
region := u.Host
path := strings.SplitN(strings.TrimPrefix(u.Path, "/"), "/", 2)
bucket := path[0]
var prefix string
if len(path) > 1 {
prefix = path[1]
}
sess, err := session.NewSession(&aws.Config{Region: &region})
if err != nil {
return nil, err
}
return &cache{
S3: s3.New(sess),
bucket: bucket,
prefix: prefix,
}, nil
}