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Using the Global Configuration Object
There are two ways to configure the SDK:
-
Set the global configuration using
AWS.Config
. -
Pass extra configuration information to a service object.
Setting global configuration with AWS.Config
is often easier to get
started, but service-level configuration can provide more control over individual
services. The global configuration specified by AWS.Config
provides default
settings for service objects that you create subsequently, simplifying their
configuration. However, you can update the configuration of individual service objects
when your needs vary from the global configuration.
Setting Global Configuration
After you load the aws-sdk
package in your code you can use the
AWS
global variable to access the SDK's classes and interact with individual
services. The SDK includes a global configuration object, AWS.Config
,
that you can use to specify the SDK configuration settings required by your
application.
Configure the SDK by setting AWS.Config
properties according to your
application needs. The following table summarizes AWS.Config
properties
commonly used to set the configuration of the SDK.
Configuration Options | Description |
---|---|
credentials
|
Required. Specifies the credentials used to determine access to services and resources. |
region
|
Required. Specifies the Region in which requests for services are made. |
maxRetries
|
Optional. Specifies the maximum number of times a given request is retried. |
logger
|
Optional. Specifies a logger object to which debugging information is written. |
update
|
Optional. Updates the current configuration with new values. |
For more information about the configuration object, see Class: AWS.Config
in the API Reference.
Global Configuration Examples
You must set the Region and the credentials in AWS.Config
. You
can set these properties as part of the AWS.Config
constructor, as
shown in the following browser script example:
var myCredentials = new AWS.CognitoIdentityCredentials({IdentityPoolId:'
IDENTITY_POOL_ID
'}); var myConfig = new AWS.Config({ credentials: myCredentials, region: 'us-west-2' });
You can also set these properties after creating AWS.Config
using
the update
method, as shown in the following example that updates
the Region:
myConfig = new AWS.Config(); myConfig.update({region: 'us-east-1'});
You can get your default credentials by calling the static
getCredentials
method of AWS.config
:
var AWS = require("aws-sdk"); AWS.config.getCredentials(function(err) { if (err) console.log(err.stack); // credentials not loaded else { console.log("Access key:", AWS.config.credentials.accessKeyId); } });
Similarly, if you have set your region correctly in your config
file, you get that value by setting the AWS_SDK_LOAD_CONFIG
environment variable is set to any value and calling the static region
property of AWS.config
:
var AWS = require("aws-sdk"); console.log("Region: ", AWS.config.region);
Setting Configuration Per Service
Each service that you use in the SDK for JavaScript is accessed through a service object that
is part of the API for that service. For example, to access the Amazon S3 service you
create the Amazon S3 service object. You can specify configuration settings that are
specific to a service as part of the constructor for that service object. When you
set configuration values on a service object, the constructor takes all of the
configuration values used by AWS.Config
, including credentials.
For example, if you need to access Amazon EC2 objects in multiple Regions, create an Amazon EC2 service object for each Region and then set the Region configuration of each service object accordingly.
var ec2_regionA = new AWS.EC2({region: 'ap-southeast-2', maxRetries: 15, apiVersion: '2014-10-01'}); var ec2_regionB = new AWS.EC2({region: 'us-east-1', maxRetries: 15, apiVersion: '2014-10-01'});
You can also set configuration values specific to a service when configuring the
SDK with AWS.Config
. The global configuration object supports many
service-specific configuration options. For more information about service-specific
configuration, see Class: AWS.Config
in the AWS SDK for JavaScript API
Reference.
Immutable Configuration Data
Global configuration changes apply to requests for all newly created service
objects. Newly created service objects are configured with the current global
configuration data first and then any local configuration options. Updates you make
to the global AWS.config
object don't apply to previously created
service objects.
Existing service objects must be manually updated with new configuration data or you must create and use a new service object that has the new configuration data. The following example creates a new Amazon S3 service object with new configuration data:
s3 = new AWS.S3(s3.config);