Source: acl.go in package cloud.google.com/go/storage

Copyright 2014 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"
	"net/http"
	"reflect"

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

ACLRole is the level of access to grant.

type ACLRole string

const (
	RoleOwner  ACLRole = "OWNER"
	RoleReader ACLRole = "READER"
	RoleWriter ACLRole = "WRITER"
)

ACLEntity refers to a user or group. They are sometimes referred to as grantees. It could be in the form of: "user-<userId>", "user-<email>", "group-<groupId>", "group-<email>", "domain-<domain>" and "project-team-<projectId>". Or one of the predefined constants: AllUsers, AllAuthenticatedUsers.

type ACLEntity string

const (
	AllUsers              ACLEntity = "allUsers"
	AllAuthenticatedUsers ACLEntity = "allAuthenticatedUsers"
)

ACLRule represents a grant for a role to an entity (user, group or team) for a Google Cloud Storage object or bucket.

type ACLRule struct {
	Entity      ACLEntity
	EntityID    string
	Role        ACLRole
	Domain      string
	Email       string
	ProjectTeam *ProjectTeam
}

ProjectTeam is the project team associated with the entity, if any.

type ProjectTeam struct {
	ProjectNumber string
	Team          string
}

ACLHandle provides operations on an access control list for a Google Cloud Storage bucket or object.

type ACLHandle struct {
	c           *Client
	bucket      string
	object      string
	isDefault   bool
	userProject string // for requester-pays buckets
}

Delete permanently deletes the ACL entry for the given entity.

func (a *ACLHandle) Delete(ctx context.Context, entity ACLEntity) (err error) {
	ctx = trace.StartSpan(ctx, "cloud.google.com/go/storage.ACL.Delete")
	defer func() { trace.EndSpan(ctx, err) }()

	if a.object != "" {
		return a.objectDelete(ctx, entity)
	}
	if a.isDefault {
		return a.bucketDefaultDelete(ctx, entity)
	}
	return a.bucketDelete(ctx, entity)
}

Set sets the role for the given entity.

func (a *ACLHandle) Set(ctx context.Context, entity ACLEntity, role ACLRole) (err error) {
	ctx = trace.StartSpan(ctx, "cloud.google.com/go/storage.ACL.Set")
	defer func() { trace.EndSpan(ctx, err) }()

	if a.object != "" {
		return a.objectSet(ctx, entity, role, false)
	}
	if a.isDefault {
		return a.objectSet(ctx, entity, role, true)
	}
	return a.bucketSet(ctx, entity, role)
}

List retrieves ACL entries.

func (a *ACLHandle) List(ctx context.Context) (rules []ACLRule, err error) {
	ctx = trace.StartSpan(ctx, "cloud.google.com/go/storage.ACL.List")
	defer func() { trace.EndSpan(ctx, err) }()

	if a.object != "" {
		return a.objectList(ctx)
	}
	if a.isDefault {
		return a.bucketDefaultList(ctx)
	}
	return a.bucketList(ctx)
}

func (a *ACLHandle) bucketDefaultList(ctx context.Context) ([]ACLRule, error) {
	var acls *raw.ObjectAccessControls
	var err error
	err = runWithRetry(ctx, func() error {
		req := a.c.raw.DefaultObjectAccessControls.List(a.bucket)
		a.configureCall(ctx, req)
		acls, err = req.Do()
		return err
	})
	if err != nil {
		return nil, err
	}
	return toObjectACLRules(acls.Items), nil
}

func (a *ACLHandle) bucketDefaultDelete(ctx context.Context, entity ACLEntity) error {
	return runWithRetry(ctx, func() error {
		req := a.c.raw.DefaultObjectAccessControls.Delete(a.bucket, string(entity))
		a.configureCall(ctx, req)
		return req.Do()
	})
}

func (a *ACLHandle) bucketList(ctx context.Context) ([]ACLRule, error) {
	var acls *raw.BucketAccessControls
	var err error
	err = runWithRetry(ctx, func() error {
		req := a.c.raw.BucketAccessControls.List(a.bucket)
		a.configureCall(ctx, req)
		acls, err = req.Do()
		return err
	})
	if err != nil {
		return nil, err
	}
	return toBucketACLRules(acls.Items), nil
}

func (a *ACLHandle) bucketSet(ctx context.Context, entity ACLEntity, role ACLRole) error {
	acl := &raw.BucketAccessControl{
		Bucket: a.bucket,
		Entity: string(entity),
		Role:   string(role),
	}
	err := runWithRetry(ctx, func() error {
		req := a.c.raw.BucketAccessControls.Update(a.bucket, string(entity), acl)
		a.configureCall(ctx, req)
		_, err := req.Do()
		return err
	})
	if err != nil {
		return err
	}
	return nil
}

func (a *ACLHandle) bucketDelete(ctx context.Context, entity ACLEntity) error {
	return runWithRetry(ctx, func() error {
		req := a.c.raw.BucketAccessControls.Delete(a.bucket, string(entity))
		a.configureCall(ctx, req)
		return req.Do()
	})
}

func (a *ACLHandle) objectList(ctx context.Context) ([]ACLRule, error) {
	var acls *raw.ObjectAccessControls
	var err error
	err = runWithRetry(ctx, func() error {
		req := a.c.raw.ObjectAccessControls.List(a.bucket, a.object)
		a.configureCall(ctx, req)
		acls, err = req.Do()
		return err
	})
	if err != nil {
		return nil, err
	}
	return toObjectACLRules(acls.Items), nil
}

func (a *ACLHandle) objectSet(ctx context.Context, entity ACLEntity, role ACLRole, isBucketDefault bool) error {
	type setRequest interface {
		Do(opts ...googleapi.CallOption) (*raw.ObjectAccessControl, error)
		Header() http.Header
	}

	acl := &raw.ObjectAccessControl{
		Bucket: a.bucket,
		Entity: string(entity),
		Role:   string(role),
	}
	var req setRequest
	if isBucketDefault {
		req = a.c.raw.DefaultObjectAccessControls.Update(a.bucket, string(entity), acl)
	} else {
		req = a.c.raw.ObjectAccessControls.Update(a.bucket, a.object, string(entity), acl)
	}
	a.configureCall(ctx, req)
	return runWithRetry(ctx, func() error {
		_, err := req.Do()
		return err
	})
}

func (a *ACLHandle) objectDelete(ctx context.Context, entity ACLEntity) error {
	return runWithRetry(ctx, func() error {
		req := a.c.raw.ObjectAccessControls.Delete(a.bucket, a.object, string(entity))
		a.configureCall(ctx, req)
		return req.Do()
	})
}

func (a *ACLHandle) configureCall(ctx context.Context, call interface{ Header() http.Header }) {
	vc := reflect.ValueOf(call)
	vc.MethodByName("Context").Call([]reflect.Value{reflect.ValueOf(ctx)})
	if a.userProject != "" {
		vc.MethodByName("UserProject").Call([]reflect.Value{reflect.ValueOf(a.userProject)})
	}
	setClientHeader(call.Header())
}

func toObjectACLRules(items []*raw.ObjectAccessControl) []ACLRule {
	var rs []ACLRule
	for _, item := range items {
		rs = append(rs, toObjectACLRule(item))
	}
	return rs
}

func toBucketACLRules(items []*raw.BucketAccessControl) []ACLRule {
	var rs []ACLRule
	for _, item := range items {
		rs = append(rs, toBucketACLRule(item))
	}
	return rs
}

func toObjectACLRule(a *raw.ObjectAccessControl) ACLRule {
	return ACLRule{
		Entity:      ACLEntity(a.Entity),
		EntityID:    a.EntityId,
		Role:        ACLRole(a.Role),
		Domain:      a.Domain,
		Email:       a.Email,
		ProjectTeam: toObjectProjectTeam(a.ProjectTeam),
	}
}

func toBucketACLRule(a *raw.BucketAccessControl) ACLRule {
	return ACLRule{
		Entity:      ACLEntity(a.Entity),
		EntityID:    a.EntityId,
		Role:        ACLRole(a.Role),
		Domain:      a.Domain,
		Email:       a.Email,
		ProjectTeam: toBucketProjectTeam(a.ProjectTeam),
	}
}

func toRawObjectACL(rules []ACLRule) []*raw.ObjectAccessControl {
	if len(rules) == 0 {
		return nil
	}
	r := make([]*raw.ObjectAccessControl, 0, len(rules))
	for _, rule := range rules {
		r = append(r, rule.toRawObjectAccessControl("")) // bucket name unnecessary
	}
	return r
}

func toRawBucketACL(rules []ACLRule) []*raw.BucketAccessControl {
	if len(rules) == 0 {
		return nil
	}
	r := make([]*raw.BucketAccessControl, 0, len(rules))
	for _, rule := range rules {
		r = append(r, rule.toRawBucketAccessControl("")) // bucket name unnecessary
	}
	return r
}

func (r ACLRule) toRawBucketAccessControl(bucket string) *raw.BucketAccessControl {
	return &raw.BucketAccessControl{
		Bucket: bucket,
		Entity: string(r.Entity),

The other fields are not settable.

	}
}

func (r ACLRule) toRawObjectAccessControl(bucket string) *raw.ObjectAccessControl {
	return &raw.ObjectAccessControl{
		Bucket: bucket,
		Entity: string(r.Entity),

The other fields are not settable.

	}
}

func toBucketProjectTeam(p *raw.BucketAccessControlProjectTeam) *ProjectTeam {
	if p == nil {
		return nil
	}
	return &ProjectTeam{
		ProjectNumber: p.ProjectNumber,
		Team:          p.Team,
	}
}

func toObjectProjectTeam(p *raw.ObjectAccessControlProjectTeam) *ProjectTeam {
	if p == nil {
		return nil
	}
	return &ProjectTeam{
		ProjectNumber: p.ProjectNumber,
		Team:          p.Team,
	}