Provide apiEndpoint override option

[JustinBeckwith]

For each API, we should support overriding the API endpoint to be used via the apiEndpoint property passed into the constructor options.

High level blocking issues:

• feat!: add apiEndpoint property to service config nodejs-common#427
• [nodejs] Add support for apiEndpoint override gapic-generator#2787

Per-API issues:

• googleapis/cloud-debug-nodejs
• googleapis/cloud-profiler-nodejs
• googleapis/cloud-trace-nodejs
• googleapis/gce-images
• googleapis/gcs-resumable-upload
• googleapis/google-api-nodejs-client
• googleapis/google-cloud-kvstore
• googleapis/nodejs-bigquery
• googleapis/nodejs-bigtable
• googleapis/nodejs-compute
• googleapis/nodejs-datastore
• googleapis/nodejs-dns
• googleapis/nodejs-error-reporting
• googleapis/nodejs-firestore
• googleapis/nodejs-logging
• googleapis/nodejs-logging-bunyan
• googleapis/nodejs-logging-winston
• googleapis/nodejs-pubsub
• googleapis/nodejs-rcloadenv
• googleapis/nodejs-resource
• googleapis/nodejs-spanner
• googleapis/nodejs-translate
• googleapis/nodejs-storage

GAPIC generated

• googleapis/nodejs-asset
• googleapis/nodejs-automl
• googleapis/nodejs-bigquery-data-transfer
• googleapis/nodejs-cloud-container
• googleapis/nodejs-containeranalysis
• googleapis/nodejs-datalabeling
• googleapis/nodejs-dataproc
• googleapis/nodejs-dialogflow
• googleapis/nodejs-dlp
• googleapis/nodejs-iot
• googleapis/nodejs-irm
• googleapis/nodejs-kms
• googleapis/nodejs-language
• googleapis/nodejs-monitoring
• googleapis/nodejs-os-login
• googleapis/nodejs-recaptcha-enterprise
• googleapis/nodejs-redis
• googleapis/nodejs-scheduler
• googleapis/nodejs-security-center
• googleapis/nodejs-speech
• googleapis/nodejs-talent
• googleapis/nodejs-tasks
• googleapis/nodejs-text-to-speech
• googleapis/nodejs-web-risk
• googleapis/nodejs-video-intelligence
• googleapis/nodejs-vision

[stephenplusplus]

We used to have this in common! Did we lose it?

[JustinBeckwith]

Oh bother - I appear to have missed this one 😆 I see that we handle the customEndpoint property in the MakeAuthenticatedRequestConfig interface, but it I don't think (need to look deeper) it's actually documented in any of the jsdoc or interfaces we provide. The hand written libs that sit over nodejs-common-grpc do provide this, but kinda all handle it manually.

The plan is different based on the type of lib, but my thinking was that in the ones that sit on nodejs-common we would do something like this:

constructor(options: StorageOptions = {}) {
   options.apiEndpoint = options.apiEndpoint ||'www.googleapis.com';
   const config = {
     baseUrl: `https://${options.apiEndpoint}/storage/v1`,
     projectIdRequired: false,
     scopes: [
       'https://www.googleapis.com/auth/cloud-platform',
       'https://www.googleapis.com/auth/devstorage.full_control',
     ],
     packageJson: require('../../package.json'),
   };
   super(config, options);
}

Does this seem like a good approach?

[stephenplusplus]

That looks right to me! We can talk specific implementation when PR time comes, but we might want to make sure to cover also handling them separately, like host and port.

[JustinBeckwith]

We got all of this covered 👍