cmd: replace Bucket.Get & json.Unmarshal with block.DownloadMeta (#1440)

Signed-off-by: zhulongcheng <zhulongcheng.dev@gmail.com>

cmd/thanos/compact.go

@@ -2,9 +2,7 @@ package main
 
 import (
  "context"
- "encoding/json"
  "fmt"
- "io/ioutil"
  "os"
  "path"
  "path/filepath"
@@ -356,26 +354,14 @@ func genMissingIndexCacheFiles(ctx context.Context, logger log.Logger, bkt objst
  return nil
  }
 
- rc, err := bkt.Get(ctx, path.Join(id.String(), block.MetaFilename))
+ meta, err := block.DownloadMeta(ctx, logger, bkt, id)
  if err != nil {
  // Probably not finished block, skip it.
- if bkt.IsObjNotFoundErr(err) {
+ if bkt.IsObjNotFoundErr(errors.Cause(err)) {
  level.Warn(logger).Log("msg", "meta file wasn't found", "block", id.String())
  return nil
  }
- return errors.Wrapf(err, "get meta for block %s", id)
- }
- defer runutil.CloseWithLogOnErr(logger, rc, "block reader")
-
- var meta metadata.Meta
-
- obj, err := ioutil.ReadAll(rc)
- if err != nil {
- return errors.Wrap(err, "read meta")
- }
-
- if err = json.Unmarshal(obj, &meta); err != nil {
- return errors.Wrap(err, "unmarshal meta")
+ return errors.Wrap(err, "download metadata")
  }
 
  // New version of compactor pushes index cache along with data block.

cmd/thanos/downsample.go

@@ -2,10 +2,7 @@ package main
 
 import (
  "context"
- "encoding/json"
- "io/ioutil"
  "os"
- "path"
  "path/filepath"
  "time"
 
@@ -148,21 +145,9 @@ func downsampleBucket(
  return nil
  }
 
- rc, err := bkt.Get(ctx, path.Join(id.String(), block.MetaFilename))
+ m, err := block.DownloadMeta(ctx, logger, bkt, id)
  if err != nil {
- return errors.Wrapf(err, "get meta for block %s", id)
- }
- defer runutil.CloseWithLogOnErr(logger, rc, "block reader")
-
- var m metadata.Meta
-
- obj, err := ioutil.ReadAll(rc)
- if err != nil {
- return errors.Wrap(err, "read meta")
- }
-
- if err = json.Unmarshal(obj, &m); err != nil {
- return errors.Wrap(err, "unmarshal meta")
+ return errors.Wrap(err, "download metadata")
  }
 
  metas = append(metas, &m)