forked from benthosdev/benthos
/
input_cloud_storage.go
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/
input_cloud_storage.go
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package gcp
import (
"context"
"errors"
"fmt"
"io"
"strings"
"sync"
"time"
"cloud.google.com/go/storage"
"google.golang.org/api/iterator"
"github.com/benthosdev/benthos/v4/internal/codec"
"github.com/benthosdev/benthos/v4/internal/component"
"github.com/benthosdev/benthos/v4/internal/component/input"
"github.com/benthosdev/benthos/v4/internal/component/interop"
"github.com/benthosdev/benthos/v4/internal/message"
"github.com/benthosdev/benthos/v4/public/service"
)
const (
// Cloud Storage Input Fields
csiFieldBucket = "bucket"
csiFieldPrefix = "prefix"
csiFieldCodec = "codec"
csiFieldDeleteObjects = "delete_objects"
)
type csiConfig struct {
Bucket string
Prefix string
Codec string
DeleteObjects bool
}
func csiConfigFromParsed(pConf *service.ParsedConfig) (conf csiConfig, err error) {
if conf.Bucket, err = pConf.FieldString(csiFieldBucket); err != nil {
return
}
if conf.Prefix, err = pConf.FieldString(csiFieldPrefix); err != nil {
return
}
if conf.Codec, err = pConf.FieldString(csiFieldCodec); err != nil {
return
}
if conf.DeleteObjects, err = pConf.FieldBool(csiFieldDeleteObjects); err != nil {
return
}
return
}
func csiSpec() *service.ConfigSpec {
return service.NewConfigSpec().
Beta().
Version("3.43.0").
Categories("Services", "GCP").
Summary(`Downloads objects within a Google Cloud Storage bucket, optionally filtered by a prefix.`).
Description(`
## Downloading Large Files
When downloading large files it's often necessary to process it in streamed parts in order to avoid loading the entire file in memory at a given time. In order to do this a `+"[`codec`](#codec)"+` can be specified that determines how to break the input into smaller individual messages.
## Metadata
This input adds the following metadata fields to each message:
`+"```"+`
- gcs_key
- gcs_bucket
- gcs_last_modified
- gcs_last_modified_unix
- gcs_content_type
- gcs_content_encoding
- All user defined metadata
`+"```"+`
You can access these metadata fields using [function interpolation](/docs/configuration/interpolation#bloblang-queries).
### Credentials
By default Benthos will use a shared credentials file when connecting to GCP services. You can find out more [in this document](/docs/guides/cloud/gcp).`).
Fields(
service.NewStringField(csiFieldBucket).
Description("The name of the bucket from which to download objects."),
service.NewStringField(csiFieldPrefix).
Description("An optional path prefix, if set only objects with the prefix are consumed.").
Default(""),
service.NewInternalField(codec.ReaderDocs).Default("all-bytes"),
service.NewBoolField(csiFieldDeleteObjects).
Description("Whether to delete downloaded objects from the bucket once they are processed.").
Advanced().
Default(false),
)
}
func init() {
err := service.RegisterBatchInput("gcp_cloud_storage", csiSpec(),
func(pConf *service.ParsedConfig, res *service.Resources) (service.BatchInput, error) {
// NOTE: We're using interop to punch an internal implementation up
// to the public plugin API. The only blocker from using the full
// public suite is the codec field.
//
// Since codecs are likely to get refactored soon I figured it
// wasn't worth investing in a public wrapper since the old style
// will likely get deprecated.
//
// This does mean that for now all codec based components will need
// to keep internal implementations. However, the config specs are
// the biggest time sink when converting to the new APIs so it's not
// a big deal to leave these tasks pending.
conf, err := csiConfigFromParsed(pConf)
if err != nil {
return nil, err
}
var rdr input.Async
if rdr, err = newGCPCloudStorageInput(conf, res); err != nil {
return nil, err
}
rdr = input.NewAsyncPreserver(rdr)
mgr := interop.UnwrapManagement(res)
i, err := input.NewAsyncReader("gcp_cloud_storage", rdr, mgr)
if err != nil {
return nil, err
}
return interop.NewUnwrapInternalInput(i), nil
})
if err != nil {
panic(err)
}
}
const (
maxGCPCloudStorageListObjectsResults = 100
)
type gcpCloudStorageObjectTarget struct {
key string
ackFn func(context.Context, error) error
}
func newGCPCloudStorageObjectTarget(key string, ackFn codec.ReaderAckFn) *gcpCloudStorageObjectTarget {
if ackFn == nil {
ackFn = func(context.Context, error) error {
return nil
}
}
return &gcpCloudStorageObjectTarget{key: key, ackFn: ackFn}
}
//------------------------------------------------------------------------------
func deleteGCPCloudStorageObjectAckFn(
bucket *storage.BucketHandle,
key string,
del bool,
prev codec.ReaderAckFn,
) codec.ReaderAckFn {
return func(ctx context.Context, err error) error {
if prev != nil {
if aerr := prev(ctx, err); aerr != nil {
return aerr
}
}
if !del || err != nil {
return nil
}
return bucket.Object(key).Delete(ctx)
}
}
//------------------------------------------------------------------------------
type gcpCloudStoragePendingObject struct {
target *gcpCloudStorageObjectTarget
obj *storage.ObjectAttrs
extracted int
scanner codec.Reader
}
type gcpCloudStorageTargetReader struct {
pending []*gcpCloudStorageObjectTarget
bucket *storage.BucketHandle
conf csiConfig
startAfter *storage.ObjectIterator
}
func newGCPCloudStorageTargetReader(
ctx context.Context,
conf csiConfig,
log *service.Logger,
bucket *storage.BucketHandle,
) (*gcpCloudStorageTargetReader, error) {
staticKeys := gcpCloudStorageTargetReader{
bucket: bucket,
conf: conf,
}
it := bucket.Objects(ctx, &storage.Query{Prefix: conf.Prefix})
for count := 0; count < maxGCPCloudStorageListObjectsResults; count++ {
obj, err := it.Next()
if errors.Is(err, iterator.Done) {
break
} else if err != nil {
return nil, fmt.Errorf("failed to list objects: %v", err)
}
ackFn := deleteGCPCloudStorageObjectAckFn(bucket, obj.Name, conf.DeleteObjects, nil)
staticKeys.pending = append(staticKeys.pending, newGCPCloudStorageObjectTarget(obj.Name, ackFn))
}
if len(staticKeys.pending) > 0 {
staticKeys.startAfter = it
}
return &staticKeys, nil
}
func (r *gcpCloudStorageTargetReader) Pop(ctx context.Context) (*gcpCloudStorageObjectTarget, error) {
if len(r.pending) == 0 && r.startAfter != nil {
r.pending = nil
for count := 0; count < maxGCPCloudStorageListObjectsResults; count++ {
obj, err := r.startAfter.Next()
if errors.Is(err, iterator.Done) {
break
} else if err != nil {
return nil, fmt.Errorf("failed to list objects: %v", err)
}
ackFn := deleteGCPCloudStorageObjectAckFn(r.bucket, obj.Name, r.conf.DeleteObjects, nil)
r.pending = append(r.pending, newGCPCloudStorageObjectTarget(obj.Name, ackFn))
}
}
if len(r.pending) == 0 {
return nil, io.EOF
}
obj := r.pending[0]
r.pending = r.pending[1:]
return obj, nil
}
func (r gcpCloudStorageTargetReader) Close(context.Context) error {
return nil
}
//------------------------------------------------------------------------------
// gcpCloudStorage is a benthos reader.Type implementation that reads messages
// from a Google Cloud Storage bucket.
type gcpCloudStorageInput struct {
conf csiConfig
objectScannerCtor codec.ReaderConstructor
keyReader *gcpCloudStorageTargetReader
objectMut sync.Mutex
object *gcpCloudStoragePendingObject
client *storage.Client
log *service.Logger
}
// newGCPCloudStorageInput creates a new Google Cloud Storage input type.
func newGCPCloudStorageInput(conf csiConfig, res *service.Resources) (*gcpCloudStorageInput, error) {
var objectScannerCtor codec.ReaderConstructor
var err error
if objectScannerCtor, err = codec.GetReader(conf.Codec, codec.NewReaderConfig()); err != nil {
return nil, fmt.Errorf("invalid google cloud storage codec: %v", err)
}
g := &gcpCloudStorageInput{
conf: conf,
objectScannerCtor: objectScannerCtor,
log: res.Logger(),
}
return g, nil
}
// Connect attempts to establish a connection to the target Google
// Cloud Storage bucket.
func (g *gcpCloudStorageInput) Connect(ctx context.Context) error {
var err error
g.client, err = storage.NewClient(context.Background())
if err != nil {
return err
}
g.keyReader, err = newGCPCloudStorageTargetReader(ctx, g.conf, g.log, g.client.Bucket(g.conf.Bucket))
return err
}
func (g *gcpCloudStorageInput) getObjectTarget(ctx context.Context) (*gcpCloudStoragePendingObject, error) {
if g.object != nil {
return g.object, nil
}
target, err := g.keyReader.Pop(ctx)
if err != nil {
return nil, err
}
objReference := g.client.Bucket(g.conf.Bucket).Object(target.key)
objAttributes, err := objReference.Attrs(ctx)
if err != nil {
_ = target.ackFn(ctx, err)
return nil, err
}
objReader, err := objReference.NewReader(context.Background())
if err != nil {
_ = target.ackFn(ctx, err)
return nil, err
}
object := &gcpCloudStoragePendingObject{
target: target,
obj: objAttributes,
}
if object.scanner, err = g.objectScannerCtor(target.key, objReader, target.ackFn); err != nil {
_ = target.ackFn(ctx, err)
return nil, err
}
g.object = object
return object, nil
}
func gcpCloudStorageMsgFromParts(p *gcpCloudStoragePendingObject, parts []*message.Part) message.Batch {
msg := message.Batch(parts)
_ = msg.Iter(func(_ int, part *message.Part) error {
part.MetaSetMut("gcs_key", p.target.key)
part.MetaSetMut("gcs_bucket", p.obj.Bucket)
part.MetaSetMut("gcs_last_modified", p.obj.Updated.Format(time.RFC3339))
part.MetaSetMut("gcs_last_modified_unix", p.obj.Updated.Unix())
part.MetaSetMut("gcs_content_type", p.obj.ContentType)
part.MetaSetMut("gcs_content_encoding", p.obj.ContentEncoding)
for k, v := range p.obj.Metadata {
part.MetaSetMut(k, v)
}
return nil
})
return msg
}
// ReadBatch attempts to read a new message from the target Google Cloud
// Storage bucket.
func (g *gcpCloudStorageInput) ReadBatch(ctx context.Context) (msg message.Batch, ackFn input.AsyncAckFn, err error) {
g.objectMut.Lock()
defer g.objectMut.Unlock()
defer func() {
if errors.Is(err, io.EOF) {
err = component.ErrTypeClosed
} else if errors.Is(err, context.Canceled) ||
errors.Is(err, context.DeadlineExceeded) ||
(err != nil && strings.HasSuffix(err.Error(), "context canceled")) {
err = component.ErrTimeout
}
}()
var object *gcpCloudStoragePendingObject
if object, err = g.getObjectTarget(ctx); err != nil {
return
}
var parts []*message.Part
var scnAckFn codec.ReaderAckFn
for {
if parts, scnAckFn, err = object.scanner.Next(ctx); err == nil {
object.extracted++
break
}
g.object = nil
if err != io.EOF {
return
}
if err = object.scanner.Close(ctx); err != nil {
g.log.Warnf("Failed to close object scanner cleanly: %v\n", err)
}
if object.extracted == 0 {
g.log.Debugf("Extracted zero messages from key %v\n", object.target.key)
}
if object, err = g.getObjectTarget(ctx); err != nil {
return
}
}
return gcpCloudStorageMsgFromParts(object, parts), func(rctx context.Context, res error) error {
return scnAckFn(rctx, res)
}, nil
}
// CloseAsync begins cleaning up resources used by this reader asynchronously.
func (g *gcpCloudStorageInput) Close(ctx context.Context) (err error) {
g.objectMut.Lock()
defer g.objectMut.Unlock()
if g.object != nil {
err = g.object.scanner.Close(ctx)
g.object = nil
}
if err == nil && g.client != nil {
err = g.client.Close()
g.client = nil
}
return
}