Making API Requests
Query requests used with Amazon CloudWatch are HTTP or HTTPS requests that use the an HTTP verb such
as GET or
POST, and a Query parameter named Action or Operation. This
documentation uses Action, although Operation is supported for
backward compatibility.
CloudWatch does not care which HTTP verb you use in a request. POST requests, GET requests, PUT requests, DELETE requests and so on all return the same result.
Amazon CloudWatch Endpoints
An endpoint is a URL that serves as an entry point for a web service. You can select a regional endpoint when you make your requests to reduce latency. For information about the endpoints used with CloudWatch, see Regions and Endpoints in the Amazon Web Services General Reference.
Query Parameters
Each query request must include some common parameters to handle authentication and selection of an action. For more information, see Common Parameters.
Some API operations take lists of parameters. These lists are specified using the
following notation: param.member.n. Values of n are integers starting
from 1. All lists of parameters must follow this notation, including lists that
contain only one parameter. For example, a Query parameter list looks like
this:
&attribute.member.1=this &attribute.member.2=that
Request Identifiers
In every response from an AWS Query API, there is a ResponseMetadata
element, which contains a RequestId element. This string is a unique
identifier that AWS assigns to provide tracking information. Although
RequestId is included as part of every response, it is not listed on
the individual API documentation pages to improve readability and to reduce
redundancy.
Query API Authentication
You can send query requests over either HTTP or HTTPS. Regardless of which protocol you use, you must include a signature in every query request. For more information about creating and including a signature, see Signing AWS API Requests in the Amazon Web Services General Reference.
Available Libraries
AWS provides libraries, sample code, tutorials, and other resources for software developers who prefer to build applications using language-specific APIs instead of the command-line tools and Query API. These libraries provide basic functions (not included in the APIs), such as request authentication, request retries, and error handling so that it is easier to get started. Libraries and resources are available for the following languages and platforms:
For libraries and sample code in all languages, see Sample Code & Libraries
Making API Requests Using the POST Method
If you don't use one of the AWS SDKs, you can make CloudWatch API requests over HTTP using the POST request method. The POST method requires you to specify the operation in the header of the request and provide the data for the operation in JSON format in the body of the request.
| Header name | Header value |
|---|---|
| host |
The Amazon CloudWatch endpoint. For example, |
| x-amz-date |
You must provide the time stamp in either the HTTP Date header or the AWS x-amz-date header. Some HTTP client libraries don't let you set the Date header. When an x-amz-date header is present, the system ignores any Date header during the request authentication. The x-amz-date header must be specified in ISO 8601 basic format. For example:
|
| Authorization |
The set of authorization parameters that AWS uses to ensure the validity and authenticity of the request. For more information about constructing this header, see Signature Version 4 Signing Process in the Amazon Web Services General Reference. |
| x-amz-target |
Specifies the CloudWatch operation:
For example, for GetMetricData the target value is the following:
|
| Content-Type |
Specifies the input format. The valid value is |
| Accept |
Specifies the response format. The valid value is |
| Content-length |
Size of the payload in bytes. |
| Content-Encoding |
Specifies the encoding format of the input and output. The valid value is |
The following is an example header for an HTTP request to return metric data in JSON format:
POST / HTTP/1.1 host: monitoring.us-east-1.amazonaws.com x-amz-target: GraniteServiceVersion20100801.GetMetricData x-amz-date: 20180112T092034Z Authorization: AWS4-HMAC-SHA256 Credential=REDACTEDREDACTED/20180411/us-east-1/monitoring/aws4_request, SignedHeaders=content-encoding;content-length;content-type;host;x-amz-date;x-amz-target, Signature=e945ed75cb91f88f138445fba02d3af93d96bfd8491e5d03588ae1b65188ff1d Content-Type: application/json Accept: application/json Content-Encoding: amz-1.0 Content-Length: 45 Connection: keep-alive
