feat(apisix): separate inline upstream

[LiteSun]

Description

Separate inline upstream in apisix backend as discussed in #319

Checklist

• I have explained the need for this PR and the problem it solves
• I have explained the changes or the new features added to this PR
• I have added tests corresponding to this change
• I have updated the documentation to reflect this change
• I have verified that this change is backward compatible

[CLAassistant]

All committers have signed the CLA.

[bzp2010]

Please ensure that code is always formatted by Prettier and avoid making changes that serve no practical purpose.

[bzp2010]

Given that service is a special case, creating an operateService function for it is a better choice. Let other resources continue using the simple operate function, while services with specific upstream expansion logic use a separate function.

See the next comment actually only one function is enough.

private operate(event: ADCSDK.Event) {
   // keep original codes
}

// handle only event for service
private operateService(event: ADCSDK.Event) {
  const operateWithRetry = (op: () => Promise<AxiosResponse>) =>
    defer(op).pipe(retry({ count: 3, delay: 100 /* or fn */ }));
  const paths = ['/apisix/admin/upstreams/xxx', '/apisix/admin/services/xxx'];
  const isUpdate = event.type !== ADCSDK.EventType.DELETE;

  return from(isUpdate ? paths : paths.reverse()).pipe(
    map(
      (url) => () =>
        this.client.request({
          method: 'DELETE',
          url,
          ...(isUpdate && {
            method: 'PUT',
            data: this.fromADC(event, this.opts.version),
          }),
        }),
    ),
    concatMap(operateWithRetry),
  );
}

[bzp2010]

Subsequently, it can be further simplified to a single operate function.

private operate(event: ADCSDK.Event) {
  const { type, resourceType, resourceId, parentId } = event;
  const isUpdate = type !== ADCSDK.EventType.DELETE;
  const PATH_PREFIX = '/apisix/admin';
  const paths = [
    `${PATH_PREFIX}/${
      resourceType === ADCSDK.ResourceType.CONSUMER_CREDENTIAL
        ? `consumers/${parentId}/credentials/${resourceId}`
        : `${resourceTypeToAPIName(resourceType)}/${resourceId}`
    }`,
  ];

  if (event.resourceType === ADCSDK.ResourceType.SERVICE) {
    const path = `${PATH_PREFIX}/upstreams/${event.resourceId}`;
    if (event.type === ADCSDK.EventType.DELETE)
      paths.push(path); // services will be deleted before upstreams
    else paths.unshift(path); // services will be created/updated after upstreams
  }

  const operateWithRetry = (op: () => Promise<AxiosResponse>) =>
    defer(op).pipe(retry({ count: 3, delay: 100 /* or fn => timeout * 2 ** count */ }));
  return from(paths).pipe(
    map(
      (path) => () =>
        this.client.request({
          method: 'DELETE',
          url: path,
          ...(isUpdate && {
            method: 'PUT',
            data: this.fromADC(event, this.opts.version),
          }),
        }),
    ),
    concatMap(operateWithRetry),
  );
}