Using Go
The IBM Cloud® Object Storage SDK for Go provides features to make the most of IBM Cloud Object Storage.
The IBM Cloud Object Storage SDK for Go is comprehensive, with many features and capabilities that exceed the scope and space of this guide. For detailed class and method documentation see the Go API documentation. Source code can be found in the GitHub repository.
Getting the SDK
Use go get
to retrieve the SDK to add it to your GOPATH workspace, or project's Go module dependencies. The SDK requires a minimum version of Go 1.10 and maximum version of Go 1.12. Future versions of Go will be supported once our
quality control process has been completed.
go get github.com/IBM/ibm-cos-sdk-go
To update the SDK use go get -u
to retrieve the latest version of the SDK.
go get -u github.com/IBM/ibm-cos-sdk-go
Import packages
After you have installed the SDK, you will need to import the packages that you require into your Go applications to use the SDK, as shown in the following example:
import (
"github.com/IBM/ibm-cos-sdk-go/aws/credentials/ibmiam"
"github.com/IBM/ibm-cos-sdk-go/aws"
"github.com/IBM/ibm-cos-sdk-go/aws/session"
"github.com/IBM/ibm-cos-sdk-go/service/s3"
)
Creating a client and sourcing Service credentials
To connect to IBM Cloud Object Storage, a client is created and configured by providing credential information (API key and service instance ID). These values can also be automatically sourced from a credentials file or from environment variables.
The credentials can be found by creating a Service Credential, or through the CLI.
Figure 1 shows an example of how to define environment variables in an application runtime at the IBM Cloud Object Storage portal. The required variables are IBM_API_KEY_ID
containing your Service Credential apikey
,
IBM_SERVICE_INSTANCE_ID
holding the resource_instance_id
also from your Service Credential, and an IBM_AUTH_ENDPOINT
with a value appropriate to your account, like https://iam.cloud.ibm.com/identity/token
.
If using environment variables to define your application credentials, use WithCredentials(ibmiam.NewEnvCredentials(aws.NewConfig())).
, replacing the similar method used in the configuration example.
If migrating from AWS S3, you can also source credentials data from ~/.aws/credentials
in the format:
[default]
aws_access_key_id = {ACCESS_KEY}
aws_secret_access_key = {SECRET_ACCESS_KEY}
If both ~/.bluemix/cos_credentials
and ~/.aws/credentials
exist, cos_credentials
takes preference.
Initializing configuration
// Constants for IBM COS values
const (
apiKey = "<API_KEY>" // eg "0viPHOY7LbLNa9eLftrtHPpTjoGv6hbLD1QalRXikliJ"
serviceInstanceID = "<RESOURCE_INSTANCE_ID>" // eg "crn:v1:bluemix:public:cloud-object-storage:global:a/3bf0d9003xxxxxxxxxx1c3e97696b71c:d6f04d83-6c4f-4a62-a165-696756d63903::"
authEndpoint = "https://iam.cloud.ibm.com/identity/token"
serviceEndpoint = "<SERVICE_ENDPOINT>" // eg "https://s3.us.cloud-object-storage.appdomain.cloud"
bucketLocation = "<LOCATION>" // eg "us"
)
// Create config
conf := aws.NewConfig().
WithRegion("us-standard").
WithEndpoint(serviceEndpoint).
WithCredentials(ibmiam.NewStaticCredentials(aws.NewConfig(), authEndpoint, apiKey, serviceInstanceID)).
WithS3ForcePathStyle(true)
Creating a client and sourcing Trusted Profile credentials
A client can be created by provding service credentials or trusted profile credentials. This section provides information to create a client using trusted profile credentials.
To connect to IBM Cloud Object Storage, a client is created and can also be configured by providing trusted profile credential information (Trusted Profile Id and CR Token file path). These values can also be automatically sourced from environment variables.
To create a Trusted Profile, establishing trust with compute resources based on specific attributes, and to define a policy to assign access to resources, see Managing access for apps in compute resources.
To learn more about establishing trust with a Kubernetes cluster, see Using Trusted Profiles in your Kubernetes and OpenShift Clusters
GO SDK supports authentication using trusted profile only in kubernetes and openshift clusters.
Trusted profile credentials can be set as environment variables during application runtime. The required variables are TRUSTED_PROFILE_ID
containing your Trusted profile Id trusted profile id
, CR_TOKEN_FILE_PATH
holding the service account token file path
, IBM_SERVICE_INSTANCE_ID
holding the resource_instance_id
from your Service Credential, and an IBM_AUTH_ENDPOINT
with a value appropriate to your
account, like https://iam.cloud.ibm.com/identity/token
. If using environment variables to define your application credentials, use WithCredentials(ibmiam.NewEnvCredentials(aws.NewConfig())).
, replacing the similar
method used in the configuration example.
Initializing configuration
// Constants for IBM COS values
const (
trustedProfileID = "<TRUSTED_PROFILE_ID>" // eg "Profile-5790481a-8fc5-46a4-bae3-d0e64ff6e0ad"
crTokenFilePath = "<SERVICE_ACCOUNT_TOKEN_FILE_PATH>" // "/var/run/secrets/tokens/service-account-token"
serviceInstanceID = "<RESOURCE_INSTANCE_ID>" // "crn:v1:bluemix:public:cloud-object-storage:global:a/<CREDENTIAL_ID_AS_GENERATED>:<SERVICE_ID_AS_GENERATED>::"
authEndpoint = "https://iam.cloud.ibm.com/identity/token"
serviceEndpoint = "<SERVICE_ENDPOINT>" // eg "https://s3.us.cloud-object-storage.appdomain.cloud"
bucketLocation = "<LOCATION>" // eg "us-standard"
)
// Create config
conf := aws.NewConfig().
WithRegion(bucketLocation).
WithEndpoint(serviceEndpoint).
WithCredentials(ibmiam.NewTrustedProfileCredentialsCR(aws.NewConfig(), authEndpoint, trustedProfileID, crtokenFilePath, serviceInstanceID)).
WithS3ForcePathStyle(true)
Both API-Key and Trusted-Profile-Id can't be set as environmental variables. Only one of them should be set, otherwise GO sdk throws an error.
For more information about endpoints, see Endpoints and storage locations.
Code Examples
Creating a new bucket
A list of valid provisioning codes for LocationConstraint
can be referenced in the Storage Classes guide. Please note that the sample uses the
appropriate location constraint for the Cold Vault storage based on the sample configuration. Your locations and configuration may vary.
func main() {
// Create client
sess := session.Must(session.NewSession())
client := s3.New(sess, conf)
// Bucket Names
newBucket := "<NEW_BUCKET_NAME>"
newColdBucket := "<NEW_COLD_BUCKET_NAME>"
input := &s3.CreateBucketInput{
Bucket: aws.String(newBucket),
}
client.CreateBucket(input)
input2 := &s3.CreateBucketInput{
Bucket: aws.String(newColdBucket),
CreateBucketConfiguration: &s3.CreateBucketConfiguration{
LocationConstraint: aws.String("us-cold"),
},
}
client.CreateBucket(input2)
d, _ := client.ListBuckets(&s3.ListBucketsInput{})
fmt.Println(d)
}
List available buckets
func main() {
// Create client
sess := session.Must(session.NewSession())
client := s3.New(sess, conf)
// Call Function
d, _ := client.ListBuckets(&s3.ListBucketsInput{})
fmt.Println(d)
}
Upload an object to a bucket
func main() {
// Create client
sess := session.Must(session.NewSession())
client := s3.New(sess, conf)
// Variables and random content to sample, replace when appropriate
bucketName := "<BUCKET_NAME>"
key := "<OBJECT_KEY>"
content := bytes.NewReader([]byte("<CONTENT>"))
input := s3.PutObjectInput{
Bucket: aws.String(bucketName),
Key: aws.String(key),
Body: content,
}
// Call Function to upload (Put) an object
result, _ := client.PutObject(&input)
fmt.Println(result)
}
List items in a bucket (List Objects V2)
func main() {
// Create client
sess := session.Must(session.NewSession())
client := s3.New(sess, conf)
// Bucket Name
Bucket := "<BUCKET_NAME>"
// Call Function
Input := &s3.ListObjectsV2Input{
Bucket: aws.String(Bucket),
}
l, e := client.ListObjectsV2(Input)
fmt.Println(l)
fmt.Println(e) // prints "<nil>"
}
// The response should be formatted like the following example:
//{
// Contents: [{
// ETag: "\"dbxxxxx53xxx7d06378204e3xxxxxx9f\"",
// Key: "file1.json",
// LastModified: 2019-10-15 22:22:52.62 +0000 UTC,
// Size: 1045,
// StorageClass: "STANDARD"
// },{
// ETag: "\"6e1xxxxx63xxxdefb440f72axxxxxxc2\"",
// Key: "file2.json",
// LastModified: 2019-10-15 23:08:10.074 +0000 UTC,
// Size: 1045,
// StorageClass: "STANDARD"
// }],
// Delimiter: "",
// IsTruncated: false,
// KeyCount: 2,
// MaxKeys: 1000,
// Name: "<BUCKET_NAME>",
// Prefix: ""
//}
Get an object's contents
func main() {
// Create client
sess := session.Must(session.NewSession())
client := s3.New(sess, conf)
// Variables
bucketName := "<NEW_BUCKET_NAME>"
key := "<OBJECT_KEY>"
// users will need to create bucket, key (flat string name)
Input := s3.GetObjectInput{
Bucket: aws.String(bucketName),
Key: aws.String(key),
}
// Call Function
res, _ := client.GetObject(&Input)
body, _ := ioutil.ReadAll(res.Body)
fmt.Println(body)
}
Delete an object from a bucket
func main() {
// Create client
sess := session.Must(session.NewSession())
client := s3.New(sess, conf)
// Bucket Name
bucket := "<BUCKET_NAME>"
input := &s3.DeleteObjectInput{
Bucket: aws.String(bucket),
Key: aws.String("<OBJECT_KEY>"),
}
d, _ := client.DeleteObject(input)
fmt.Println(d)
}
Delete multiple objects from a bucket
func main() {
// Create client
sess := session.Must(session.NewSession())
client := s3.New(sess, conf)
// Bucket Name
bucket := "<BUCKET_NAME>"
input := &s3.DeleteObjectsInput{
Bucket: aws.String(bucket),
Delete: &s3.Delete{
Objects: []*s3.ObjectIdentifier{
{
Key: aws.String("<OBJECT_KEY1>"),
},
{
Key: aws.String("<OBJECT_KEY2>"),
},
{
Key: aws.String("<OBJECT_KEY3>"),
},
},
Quiet: aws.Bool(false),
},
}
d, _ := client.DeleteObjects(input)
fmt.Println(d)
}
Delete a bucket
func main() {
// Bucket Name
bucket := "<BUCKET_NAME>"
// Create client
sess := session.Must(session.NewSession())
client := s3.New(sess, conf)
input := &s3.DeleteBucketInput{
Bucket: aws.String(bucket),
}
d, _ := client.DeleteBucket(input)
fmt.Println(d)
}
Run a manual multi-part upload
func main() {
// Variables
bucket := "<BUCKET_NAME>"
key := "<OBJECT_KEY>"
content := bytes.NewReader([]byte("<CONTENT>"))
input := s3.CreateMultipartUploadInput{
Bucket: aws.String(bucket),
Key: aws.String(key),
}
// Create client
sess := session.Must(session.NewSession())
client := s3.New(sess, conf)
upload, _ := client.CreateMultipartUpload(&input)
uploadPartInput := s3.UploadPartInput{
Bucket: aws.String(bucket),
Key: aws.String(key),
PartNumber: aws.Int64(int64(1)),
UploadId: upload.UploadId,
Body: content,
}
var completedParts []*s3.CompletedPart
completedPart, _ := client.UploadPart(&uploadPartInput)
completedParts = append(completedParts, &s3.CompletedPart{
ETag: completedPart.ETag,
PartNumber: aws.Int64(int64(1)),
})
completeMPUInput := s3.CompleteMultipartUploadInput{
Bucket: aws.String(bucket),
Key: aws.String(key),
MultipartUpload: &s3.CompletedMultipartUpload{
Parts: completedParts,
},
UploadId: upload.UploadId,
}
d, _ := client.CompleteMultipartUpload(&completeMPUInput)
fmt.Println(d)
}
Using Key Protect
Key Protect can be added to a storage bucket to manage encryption keys. All data is encrypted in IBM COS, but Key Protect provides a service for generating, rotating, and controlling access to encryption keys by using a centralized service.
Before You Begin
The following items are necessary to create a bucket with Key-Protect enabled:
- A Key Protect service provisioned
- A Root key available (either generated or imported)
Retrieving the Root Key CRN
- Retrieve the instance ID for your Key Protect service
- Use the Key Protect API to retrieve all your available keys
- You can either use
curl
commands or an API REST Client such as Postman to access the Key Protect API.
- You can either use
- Retrieve the CRN of the root key you use to enabled Key Protect on your bucket. The CRN looks similar to below:
crn:v1:bluemix:public:kms:us-south:a/3d624cd74a0dea86ed8efe3101341742:90b6a1db-0fe1-4fe9-b91e-962c327df531:key:0bg3e33e-a866-50f2-b715-5cba2bc93234
Creating a bucket with Key Protect enabled
func main() {
// Create client
sess := session.Must(session.NewSession())
client := s3.New(sess, conf)
// Bucket Names
newBucket := "<NEW_BUCKET_NAME>"
fmt.Println("Creating new encrypted bucket:", newBucket)
input := &s3.CreateBucketInput{
Bucket: aws.String(newBucket),
IBMSSEKPCustomerRootKeyCrn: aws.String("<ROOT-KEY-CRN>"),
IBMSSEKPEncryptionAlgorithm:aws.String("<ALGORITHM>"),
}
client.CreateBucket(input)
// List Buckets
d, _ := client.ListBuckets(&s3.ListBucketsInput{})
fmt.Println(d)
}
Key Values
<NEW_BUCKET_NAME>
- The name of the new bucket.<ROOT-KEY-CRN>
- CRN of the Root Key that is obtained from the Key Protect service.<ALGORITHM>
- The encryption algorithm that is used for new objects added to the bucket (Default is AES256).
Use the transfer manager
func main() {
// Variables
bucket := "<BUCKET_NAME>"
key := "<OBJECT_KEY>"
// Create client
sess := session.Must(session.NewSession())
client := s3.New(sess, conf)
// Create an uploader with S3 client and custom options
uploader := s3manager.NewUploaderWithClient(client, func(u *s3manager.Uploader) {
u.PartSize = 5 * 1024 * 1024 // 64MB per part
})
// make a buffer of 5MB
buffer := make([]byte, 15*1024*1024, 15*1024*1024)
random := rand.New(rand.NewSource(time.Now().Unix()))
random.Read(buffer)
input := &s3manager.UploadInput{
Bucket: aws.String(bucket),
Key: aws.String(key),
Body: io.ReadSeeker(bytes.NewReader(buffer)),
}
// Perform an upload.
d, _ := uploader.Upload(input)
fmt.Println(d)
// Perform upload with options different than the those in the Uploader.
f, _ := uploader.Upload(input, func(u *s3manager.Uploader) {
u.PartSize = 10 * 1024 * 1024 // 10MB part size
u.LeavePartsOnError = true // Don't delete the parts if the upload fails.
})
fmt.Println(f)
}
Getting an extended listing
func main() {
// Create client
sess := session.Must(session.NewSession())
client := s3.New(sess, conf)
input := new(s3.ListBucketsExtendedInput).SetMaxKeys(<MAX_KEYS>).SetMarker("<MARKER>").SetPrefix("<PREFIX>")
output, _ := client.ListBucketsExtended(input)
jsonBytes, _ := json.MarshalIndent(output, " ", " ")
fmt.Println(string(jsonBytes))
}
Key Values
<MAX_KEYS>
- Maximum number of buckets to retrieve in the request.<MARKER>
- The bucket name to start the listing (Skip until this bucket).<PREFIX
- Only include buckets whose name start with this prefix.
Getting an extended listing with pagination
func main() {
// Create client
sess := session.Must(session.NewSession())
client := s3.New(sess, conf)
i := 0
input := new(s3.ListBucketsExtendedInput).SetMaxKeys(<MAX_KEYS>).SetMarker("<MARKER>").SetPrefix("<PREFIX>")
output, _ := client.ListBucketsExtended(input)
for _, bucket := range output.Buckets {
fmt.Println(i, "\t\t", *bucket.Name, "\t\t", *bucket.LocationConstraint, "\t\t", *bucket.CreationDate)
}
}
Key Values
<MAX_KEYS>
- Maximum number of buckets to retrieve in the request.<MARKER>
- The bucket name to start the listing (Skip until this bucket).<PREFIX
- Only include buckets whose name start with this prefix.
Archive Tier Support
You can automatically archive objects after a specified length of time or after a specified date. Once archived, a temporary copy of an object can be restored for access as needed. Please note the time required to restore the temporary copy of the object(s) may take up to 12 hours.
To use the example provided, provide your own configuration—including replacing <apikey>
and other bracketed <...>
information, while keeping in mind that using environment variables are more secure, and
you should not put credentials in code that will be versioned.
An archive policy is set at the bucket level by calling the PutBucketLifecycleConfiguration
method on a client instance. A newly added or modified archive policy applies to new objects uploaded and does not affect existing objects.
func main() {
// Create Client
sess := session.Must(session.NewSession())
client := s3.New(sess, conf)
// PUT BUCKET LIFECYCLE CONFIGURATION
// Replace <BUCKET_NAME> with the name of the bucket
lInput := &s3.PutBucketLifecycleConfigurationInput{
Bucket: aws.String("<BUCKET_NAME>"),
LifecycleConfiguration: &s3.LifecycleConfiguration{
Rules: []*s3.LifecycleRule{
{
Status: aws.String("Enabled"),
Filter: &s3.LifecycleRuleFilter{},
ID: aws.String("id3"),
Transitions: []*s3.Transition{
{
Days: aws.Int64(5),
StorageClass: aws.String("Glacier"),
},
},
},
},
},
}
l, e := client.PutBucketLifecycleConfiguration(lInput)
fmt.Println(l) // should print an empty bracket
fmt.Println(e) // should print <nil>
// GET BUCKET LIFECYCLE CONFIGURATION
gInput := &s3.GetBucketLifecycleConfigurationInput{
Bucket: aws.String("<bucketname>"),
}
g, e := client.GetBucketLifecycleConfiguration(gInput)
fmt.Println(g)
fmt.Println(e) // see response for results
// RESTORE OBJECT
// Replace <OBJECT_KEY> with the appropriate key
rInput := &s3.RestoreObjectInput{
Bucket: aws.String("<BUCKET_NAME>"),
Key: aws.String("<OBJECT_KEY>"),
RestoreRequest: &s3.RestoreRequest{
Days: aws.Int64(100),
GlacierJobParameters: &s3.GlacierJobParameters{
Tier: aws.String("Bulk"),
},
},
}
r, e := client.RestoreObject(rInput)
fmt.Println(r)
fmt.Println(e)
}
The typical response is exemplified here.
{
Rules: [{
Filter: {
},
ID: "id3",
Status: "Enabled",
Transitions: [{
Days: 5,
StorageClass: "GLACIER"
}]
}]
}
Immutable Object Storage
Users can configure buckets with an Immutable Object Storage policy to prevent objects from being modified or deleted for a defined period of time. The retention period can be specified on a per-object basis, or objects can inherit a default retention period set on the bucket. It is also possible to set open-ended and permanent retention periods. Immutable Object Storage meets the rules set forth by the SEC governing record retention, and IBM Cloud administrators are unable to bypass these restrictions.
Immutable Object Storage does not support Aspera transfers via the SDK to upload objects or directories at this stage.
func main() {
// Create Client
sess := session.Must(session.NewSession())
client := s3.New(sess, conf)
// Create a bucket
input := &s3.CreateBucketInput{
Bucket: aws.String("<BUCKET_NAME>"),
}
d, e := client.CreateBucket(input)
fmt.Println(d) // should print an empty bracket
fmt.Println(e) // should print <nil>
// PUT BUCKET PROTECTION CONFIGURATION
pInput := &s3.PutBucketProtectionConfigurationInput{
Bucket: aws.String("<BUCKET_NAME>"),
ProtectionConfiguration: &s3.ProtectionConfiguration{
DefaultRetention: &s3.BucketProtectionDefaultRetention{
Days: aws.Int64(100),
},
MaximumRetention: &s3.BucketProtectionMaximumRetention{
Days: aws.Int64(1000),
},
MinimumRetention: &s3.BucketProtectionMinimumRetention{
Days: aws.Int64(10),
},
Status: aws.String("Retention"),
},
}
p, e := client.PutBucketProtectionConfiguration(pInput)
fmt.Println(p)
fmt.Println(e) // see response for results
// GET BUCKET PROTECTION CONFIGURATION
gInput := &s3.GetBucketProtectionConfigurationInput{
Bucket: aws.String("<BUCKET_NAME>"),
}
g, e := client.GetBucketProtectionConfiguration(gInput)
fmt.Println(g)
fmt.Println(e)
}
The typical response is exemplified here.
{
ProtectionConfiguration: {
DefaultRetention: {
Days: 100
},
MaximumRetention: {
Days: 1000
},
MinimumRetention: {
Days: 10
},
Status: "COMPLIANCE"
}
}
Create a hosted static website
This operation requires permissions, as only the bucket owner is typically permitted to configure a bucket to host a static website. The parameters determine the default suffix for visitors to the site as well as an optional error document included here to complete the example.
func main() {
// Create Client
sess := session.Must(session.NewSession())
client := s3.New(sess, conf)
// Create a bucket
input := &s3.CreateBucketInput{
Bucket: aws.String("<BUCKET_NAME>"),
}
d, e := client.CreateBucket(input)
fmt.Println(d) // should print an empty bracket
fmt.Println(e) // should print <nil>
// PUT BUCKET WEBSITE
pInput := s3.PutBucketWebsiteInput{
Bucket: input,
WebsiteConfiguration: &s3.WebsiteConfiguration{
IndexDocument: &s3.IndexDocument{
Suffix: aws.String("index.html"),
},
},
}
pInput.WebsiteConfiguration.ErrorDocument = &s3.ErrorDocument{
Key: aws.String("error.html"),
}
p, e := client.PutBucketWebsite(¶ms)
fmt.Println(p)
fmt.Println(e) // see response for results
}
Next Steps
If you haven't already, please see the detailed class and method documentation available at the Go API documentation.