path: root/vendor/cloud.google.com/go/storage/copy.go

// Copyright 2016 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package storage

import (
    "context"
    "errors"
    "fmt"

    "cloud.google.com/go/internal/trace"
    raw "google.golang.org/api/storage/v1"
)

// CopierFrom creates a Copier that can copy src to dst.
// You can immediately call Run on the returned Copier, or
// you can configure it first.
//
// For Requester Pays buckets, the user project of dst is billed, unless it is empty,
// in which case the user project of src is billed.
func (dst *ObjectHandle) CopierFrom(src *ObjectHandle) *Copier {
    return &Copier{dst: dst, src: src}
}

// A Copier copies a source object to a destination.
type Copier struct {
    // ObjectAttrs are optional attributes to set on the destination object.
    // Any attributes must be initialized before any calls on the Copier. Nil
    // or zero-valued attributes are ignored.
    ObjectAttrs

    // RewriteToken can be set before calling Run to resume a copy
    // operation. After Run returns a non-nil error, RewriteToken will
    // have been updated to contain the value needed to resume the copy.
    RewriteToken string

    // ProgressFunc can be used to monitor the progress of a multi-RPC copy
    // operation. If ProgressFunc is not nil and copying requires multiple
    // calls to the underlying service (see
    // https://cloud.google.com/storage/docs/json_api/v1/objects/rewrite), then
    // ProgressFunc will be invoked after each call with the number of bytes of
    // content copied so far and the total size in bytes of the source object.
    //
    // ProgressFunc is intended to make upload progress available to the
    // application. For example, the implementation of ProgressFunc may update
    // a progress bar in the application's UI, or log the result of
    // float64(copiedBytes)/float64(totalBytes).
    //
    // ProgressFunc should return quickly without blocking.
    ProgressFunc func(copiedBytes, totalBytes uint64)

    // The Cloud KMS key, in the form projects/P/locations/L/keyRings/R/cryptoKeys/K,
    // that will be used to encrypt the object. Overrides the object's KMSKeyName, if
    // any.
    //
    // Providing both a DestinationKMSKeyName and a customer-supplied encryption key
    // (via ObjectHandle.Key) on the destination object will result in an error when
    // Run is called.
    DestinationKMSKeyName string

    dst, src *ObjectHandle
}

// Run performs the copy.
func (c *Copier) Run(ctx context.Context) (attrs *ObjectAttrs, err error) {
    ctx = trace.StartSpan(ctx, "cloud.google.com/go/storage.Copier.Run")
    defer func() { trace.EndSpan(ctx, err) }()

    if err := c.src.validate(); err != nil {
        return nil, err
    }
    if err := c.dst.validate(); err != nil {
        return nil, err
    }
    if c.DestinationKMSKeyName != "" && c.dst.encryptionKey != nil {
        return nil, errors.New("storage: cannot use DestinationKMSKeyName with a customer-supplied encryption key")
    }
    // Convert destination attributes to raw form, omitting the bucket.
    // If the bucket is included but name or content-type aren't, the service
    // returns a 400 with "Required" as the only message. Omitting the bucket
    // does not cause any problems.
    rawObject := c.ObjectAttrs.toRawObject("")
    for {
        res, err := c.callRewrite(ctx, rawObject)
        if err != nil {
            return nil, err
        }
        if c.ProgressFunc != nil {
            c.ProgressFunc(uint64(res.TotalBytesRewritten), uint64(res.ObjectSize))
        }
        if res.Done { // Finished successfully.
            return newObject(res.Resource), nil
        }
    }
}

func (c *Copier) callRewrite(ctx context.Context, rawObj *raw.Object) (*raw.RewriteResponse, error) {
    call := c.dst.c.raw.Objects.Rewrite(c.src.bucket, c.src.object, c.dst.bucket, c.dst.object, rawObj)

    call.Context(ctx).Projection("full")
    if c.RewriteToken != "" {
        call.RewriteToken(c.RewriteToken)
    }
    if c.DestinationKMSKeyName != "" {
        call.DestinationKmsKeyName(c.DestinationKMSKeyName)
    }
    if c.PredefinedACL != "" {
        call.DestinationPredefinedAcl(c.PredefinedACL)
    }
    if err := applyConds("Copy destination", c.dst.gen, c.dst.conds, call); err != nil {
        return nil, err
    }
    if c.dst.userProject != "" {
        call.UserProject(c.dst.userProject)
    } else if c.src.userProject != "" {
        call.UserProject(c.src.userProject)
    }
    if err := applySourceConds(c.src.gen, c.src.conds, call); err != nil {
        return nil, err
    }
    if err := setEncryptionHeaders(call.Header(), c.dst.encryptionKey, false); err != nil {
        return nil, err
    }
    if err := setEncryptionHeaders(call.Header(), c.src.encryptionKey, true); err != nil {
        return nil, err
    }
    var res *raw.RewriteResponse
    var err error
    setClientHeader(call.Header())
    err = runWithRetry(ctx, func() error { res, err = call.Do(); return err })
    if err != nil {
        return nil, err
    }
    c.RewriteToken = res.RewriteToken
    return res, nil
}

// ComposerFrom creates a Composer that can compose srcs into dst.
// You can immediately call Run on the returned Composer, or you can
// configure it first.
//
// The encryption key for the destination object will be used to decrypt all
// source objects and encrypt the destination object. It is an error
// to specify an encryption key for any of the source objects.
func (dst *ObjectHandle) ComposerFrom(srcs ...*ObjectHandle) *Composer {
    return &Composer{dst: dst, srcs: srcs}
}

// A Composer composes source objects into a destination object.
//
// For Requester Pays buckets, the user project of dst is billed.
type Composer struct {
    // ObjectAttrs are optional attributes to set on the destination object.
    // Any attributes must be initialized before any calls on the Composer. Nil
    // or zero-valued attributes are ignored.
    ObjectAttrs

    dst  *ObjectHandle
    srcs []*ObjectHandle
}

// Run performs the compose operation.
func (c *Composer) Run(ctx context.Context) (attrs *ObjectAttrs, err error) {
    ctx = trace.StartSpan(ctx, "cloud.google.com/go/storage.Composer.Run")
    defer func() { trace.EndSpan(ctx, err) }()

    if err := c.dst.validate(); err != nil {
        return nil, err
    }
    if len(c.srcs) == 0 {
        return nil, errors.New("storage: at least one source object must be specified")
    }

    req := &raw.ComposeRequest{}
    // Compose requires a non-empty Destination, so we always set it,
    // even if the caller-provided ObjectAttrs is the zero value.
    req.Destination = c.ObjectAttrs.toRawObject(c.dst.bucket)
    for _, src := range c.srcs {
        if err := src.validate(); err != nil {
            return nil, err
        }
        if src.bucket != c.dst.bucket {
            return nil, fmt.Errorf("storage: all source objects must be in bucket %q, found %q", c.dst.bucket, src.bucket)
        }
        if src.encryptionKey != nil {
            return nil, fmt.Errorf("storage: compose source %s.%s must not have encryption key", src.bucket, src.object)
        }
        srcObj := &raw.ComposeRequestSourceObjects{
            Name: src.object,
        }
        if err := applyConds("ComposeFrom source", src.gen, src.conds, composeSourceObj{srcObj}); err != nil {
            return nil, err
        }
        req.SourceObjects = append(req.SourceObjects, srcObj)
    }

    call := c.dst.c.raw.Objects.Compose(c.dst.bucket, c.dst.object, req).Context(ctx)
    if err := applyConds("ComposeFrom destination", c.dst.gen, c.dst.conds, call); err != nil {
        return nil, err
    }
    if c.dst.userProject != "" {
        call.UserProject(c.dst.userProject)
    }
    if c.PredefinedACL != "" {
        call.DestinationPredefinedAcl(c.PredefinedACL)
    }
    if err := setEncryptionHeaders(call.Header(), c.dst.encryptionKey, false); err != nil {
        return nil, err
    }
    var obj *raw.Object
    setClientHeader(call.Header())
    err = runWithRetry(ctx, func() error { obj, err = call.Do(); return err })
    if err != nil {
        return nil, err
    }
    return newObject(obj), nil
}