@looker/sdk-rtl
v21.6.3
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Looker SDK Runtime Library
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Looker SDK Runtime Library
The Looker TypeScript/JavaScript SDK depends on the runtime code in this package.
The source code in this package is almost all completely generic REST request/response processing code.
The @looker/sdk
and @looker/sdk-node
packages are updated with every Looker release. This package has a much longer update/release cycle.
HTTP request behavior options
The Browser and Node transport layers can be configured with both SDK-wide settings and request-specific optional properties that modify the
behavior of a request. These properties are documented in ITransportSettings
.
When initializing the SDK, these values configure the default behavior for every HTTP request.
The behavior of any specific request can be modified by passing different values in the options
property of the request method.
Some of these request configuration properties are further explained below.
timeout
If not explicitly configured, the HTTP request timeout
period is 120 seconds, which is supported in both Node and Browser transport layers via an
AbortSignal.timeout()
instance created for each HTTP request.
To override the timeout period for a long-running HTTP request, pass a timeout
override value in the options
parameter for a request.
const xp = new BrowserTransport({ maxTries: 1 } as ITransportSettings);
const response = await xp.request(
'GET',
'https://my.slow.page',
undefined,
undefined,
undefined,
{
timeout: 15 * 60, // 15 minute timeout
}
);
signal
The signal
property is an optional AbortSignal
argument to pass to a transport's request method. This property
can be used to cancel a request via programmatic or UI control. The following example is adapted from browserTransport.spec.ts:
// times out request in 250 ms via AbortSignal "cancellation"
const xp = new BrowserTransport({ maxTries: 1 } as ITransportSettings);
const signal = AbortSignal.timeout(250);
await expect(
xp.request(
'GET',
'https://timeout.in?ms=2000',
undefined,
undefined,
undefined,
{
signal,
}
)
).rejects.toThrowError('The operation was aborted.');
maxTries
To enable automatic retries on request methods, set maxTries
to a number > 1.
If maxTries
is > 1 and the HTTP response is a 202
, 429
, or 503
, an exponential backoff
will be used until a success response is received or maxTries
is exceeded.
The waiting period before the retry will use the number of seconds provided in a Retry-After header
if found.
NOTE: Automatic retry on 202
varies from the suggestion made in Microsoft's long-running operations
design pattern, where 202
is not considered a retryable response.
waitHandler
The waitHandler
property is a Waitable
callback that can be used to provide custom messaging and handling of the waiting period between automatic retries. This currently has
an alpha status, meaning it is subject to change or removal without notice.
/** Alpha: Properties for an async Waitable retry handler */
export interface IWait {
/** HTTP request that responded with a retry code */
request: IRawRequest;
/** HTTP response that is a retry */
response: IRawResponse;
/** Attempt number for the retry */
attempt: number;
/** Time in milliseconds to wait before retrying */
waitMS: number;
}
/** Alpha: Response from a Waitable function */
export interface IWaitResponse {
/** cancel, retry, or error are the allowed responses for the retryable waiter */
response: 'cancel' | 'retry' | 'error';
/** Optional reason for the response */
reason?: string;
}
/** Alpha: Waitable function override for retrying an HTTP request */
export type Waitable = (waiting: IWait) => Promise<IWaitResponse>;
verify_ssl
Setting verify_ssl
to false
will disable SSL certificate verification. THIS IS NOT RECOMMENDED and should only be used in development scenarios where self-signed certificates are used locally.
The default value forverify_ssl
is true
.