feat: integrate cloudevents module

[grant]

Integrates the CloudEvents SDK for the Node Functions Framework. Does not change functionality.

• Adds cloudevents module
• Removes internal interfaces
• Removes binary CloudEvent support for event signature. (This signature should not receive or support CloudEvents)
• Updates tests

Potential Improvements

• Filed bug with CE TS interface: Remove Unknown Type From Interfaces cloudevents/sdk-javascript#294
• Not sure the best way to figure out if a HTTP request is a CE: isCloudEvent Function cloudevents/sdk-javascript#295

Production Impact

Should not have impact on GCF invoker as:

• We don't currently use wrapCloudEventFunction in GCF
• We don't see isBinaryCloudEvent resolving to true in wrapEventFunction
• cloudevents bundle size is reasonable at <200kB: https://bundlephobia.com/[email protected]

CC: @lance @grayside

[grant]

There might be some issues to address before landing this.

Current errors:

 tsc -p .

node_modules/cloudevents/dist/event/cloudevent.d.ts:15:5 - error TS1127: Invalid character.

15     #private;
       

node_modules/cloudevents/dist/event/cloudevent.d.ts:15:6 - error TS7008: Member 'private' implicitly has an 'any' type.

15     #private;
        ~~~~~~~

node_modules/cloudevents/dist/transport/index.d.ts:3:10 - error TS1005: 'from' expected.

3 export * as http from "./http/headers";
           ~~

node_modules/cloudevents/dist/transport/index.d.ts:3:10 - error TS1141: String literal expected.

3 export * as http from "./http/headers";
           ~~

node_modules/cloudevents/dist/transport/index.d.ts:3:13 - error TS1005: ';' expected.

3 export * as http from "./http/headers";
              ~~~~

node_modules/cloudevents/dist/transport/index.d.ts:3:13 - error TS2304: Cannot find name 'http'.

3 export * as http from "./http/headers";
              ~~~~

node_modules/cloudevents/dist/transport/index.d.ts:3:18 - error TS1005: ';' expected.

3 export * as http from "./http/headers";
                   ~~~~

node_modules/cloudevents/dist/transport/index.d.ts:3:18 - error TS2304: Cannot find name 'from'.

3 export * as http from "./http/headers";
                   ~~~~

node_modules/cloudevents/dist/transport/index.d.ts:3:23 - error TS1005: ';' expected.

3 export * as http from "./http/headers";         

cloudevents/sdk-javascript#272

[lance]

@grant consider upgrading your typescript dependency. In the cloudevents module, we are using 3.8.3 and with that version tsc does not suffer from these problems.

[hdp617]

LGTM. Assuming typescript is updated and the presubmit checks pass.

[grant]

Merge with master should pull the latest TS version now.

[grant]

I think there needs to be some work with fixing the invoker for the current CE implementation before adding this module.

I've been getting into feature-creep trying to fix too many things at once. So I'll close this PR and we should continue with a smaller PR.