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package data
import (
"bytes"
"context"
"encoding/json"
"io"
"mime"
"net/url"
"path"
"strings"
gaws "github.com/hairyhenderson/gomplate/v3/aws"
"github.com/hairyhenderson/gomplate/v3/env"
"github.com/pkg/errors"
"gocloud.dev/blob"
"gocloud.dev/blob/gcsblob"
"gocloud.dev/blob/s3blob"
"gocloud.dev/gcp"
)
func readBlob(ctx context.Context, source *Source, args ...string) (output []byte, err error) {
if len(args) >= 2 {
return nil, errors.New("maximum two arguments to blob datasource: alias, extraPath")
}
key := source.URL.Path
if len(args) == 1 {
key = path.Join(key, args[0])
}
opener, err := newOpener(ctx, source.URL)
if err != nil {
return nil, err
}
mux := blob.URLMux{}
mux.RegisterBucket(source.URL.Scheme, opener)
u := blobURL(source.URL)
bucket, err := mux.OpenBucket(ctx, u)
if err != nil {
return nil, err
}
defer bucket.Close()
var r func(context.Context, *blob.Bucket, string) (string, []byte, error)
if strings.HasSuffix(key, "/") {
r = listBucket
} else {
r = getBlob
}
mediaType, data, err := r(ctx, bucket, key)
if mediaType != "" {
source.mediaType = mediaType
}
return data, err
}
// create the correct kind of blob.BucketURLOpener for the given URL
func newOpener(ctx context.Context, u *url.URL) (opener blob.BucketURLOpener, err error) {
switch u.Scheme {
case "s3":
// set up a "regular" gomplate AWS SDK session
sess := gaws.SDKSession()
// see https://gocloud.dev/concepts/urls/#muxes
opener = &s3blob.URLOpener{ConfigProvider: sess}
case "gs":
creds, err := gcp.DefaultCredentials(ctx)
if err != nil {
return nil, errors.Wrap(err, "failed to retrieve GCP credentials")
}
client, err := gcp.NewHTTPClient(
gcp.DefaultTransport(),
gcp.CredentialsTokenSource(creds))
if err != nil {
return nil, errors.Wrap(err, "failed to create GCP HTTP client")
}
opener = &gcsblob.URLOpener{
Client: client,
}
}
return opener, nil
}
func getBlob(ctx context.Context, bucket *blob.Bucket, key string) (mediaType string, data []byte, err error) {
key = strings.TrimPrefix(key, "/")
attr, err := bucket.Attributes(ctx, key)
if err != nil {
return "", nil, errors.Wrapf(err, "failed to retrieve attributes for %s", key)
}
if attr.ContentType != "" {
mt, _, e := mime.ParseMediaType(attr.ContentType)
if e != nil {
return "", nil, e
}
mediaType = mt
}
data, err = bucket.ReadAll(ctx, key)
return mediaType, data, errors.Wrapf(err, "failed to read %s", key)
}
// calls the bucket listing API, returning a JSON Array
func listBucket(ctx context.Context, bucket *blob.Bucket, path string) (mediaType string, data []byte, err error) {
path = strings.TrimPrefix(path, "/")
opts := &blob.ListOptions{
Prefix: path,
Delimiter: "/",
}
li := bucket.List(opts)
keys := []string{}
for {
obj, err := li.Next(ctx)
if err == io.EOF {
break
}
if err != nil {
return "", nil, err
}
keys = append(keys, strings.TrimPrefix(obj.Key, path))
}
var buf bytes.Buffer
enc := json.NewEncoder(&buf)
if err := enc.Encode(keys); err != nil {
return "", nil, err
}
b := buf.Bytes()
// chop off the newline added by the json encoder
data = b[:len(b)-1]
return jsonArrayMimetype, data, nil
}
// copy/sanitize the URL for the Go CDK - it doesn't like params it can't parse
func blobURL(u *url.URL) string {
out := cloneURL(u)
q := out.Query()
for param := range q {
switch u.Scheme {
case "s3":
switch param {
case "region", "endpoint", "disableSSL", "s3ForcePathStyle":
default:
q.Del(param)
}
case "gs":
switch param {
case "access_id", "private_key_path":
default:
q.Del(param)
}
}
}
if u.Scheme == "s3" {
// handle AWS_S3_ENDPOINT env var
endpoint := env.Getenv("AWS_S3_ENDPOINT")
if endpoint != "" {
q.Set("endpoint", endpoint)
}
}
out.RawQuery = q.Encode()
return out.String()
}
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