Extraction function scaffolding in base folder (#29)

Review #28 before this one.

## Summary

One of last week's action point was to ensure worker file split that is
native for DevRev's snap-in development.

Example from Asana
https://github.com/devrev/airdrop-asana-snap-in/blob/7f2e49e906a9b3e3c7d13b3391fdb588dec2ad7b/code/src/functions/extraction/index.ts#L36-L55

Note that this is just suggestion (not a snap-in expert 😁). Curious to
hear your suggestions.

- [#ISS-217157](https://app.devrev.ai/devrev/works/ISS-217157)

---------

Co-authored-by: gasperzgonec <gasper.zgonec@devrev.ai>

Author: tjazerzen

base_folder/src/function-factory.ts

@@ -1,5 +1,8 @@
+import extraction from './functions/extraction';
+
 export const functionFactory = {
   // Add your functions here
+  extraction,
 } as const;
 
 export type FunctionFactoryType = keyof typeof functionFactory;

base_folder/src/functions/extraction/index.ts

@@ -0,0 +1,42 @@
+import { convertToAirdropEvent } from '../../core/utils';
+import { FunctionInput } from '../../core/types';
+import { spawn, EventType } from '@devrev/ts-adaas';
+
+export interface ExtractorState {}
+
+export const initialState: ExtractorState = {};
+
+
+function getWorkerPerExtractionPhase(event: FunctionInput) {
+  let path;
+  switch (event.payload.event_type) {
+    case EventType.ExtractionExternalSyncUnitsStart:
+      path = __dirname + '/workers/external-sync-units-extraction';
+      break;
+    case EventType.ExtractionMetadataStart:
+      path = __dirname + '/workers/metadata-extraction';
+      break;
+    case EventType.ExtractionDataStart:
+    case EventType.ExtractionDataContinue:
+      path = __dirname + '/workers/data-extraction';
+      break;
+    case EventType.ExtractionAttachmentsStart:
+    case EventType.ExtractionAttachmentsContinue:
+      path = __dirname + '/workers/attachments-extraction';
+      break;
+  }
+  return path;
+}
+
+const run = async (events: FunctionInput[]) => {
+  for (const event of events) {
+    const file = getWorkerPerExtractionPhase(event);
+    await spawn({
+      event: convertToAirdropEvent(event),
+      workerPath: file,
+      initialState: initialState,
+    });
+  }
+};
+
+export default run;

base_folder/src/functions/extraction/workers/attachments-extraction.ts

@@ -0,0 +1,9 @@
+import { ExtractorEventType, processTask } from '@devrev/ts-adaas';
+import { ExtractorState } from "../index";
+
+processTask<ExtractorState>({
+  task: async ({ adapter }) => {},
+  onTimeout: async ({ adapter }) => {
+    await adapter.emit(ExtractorEventType.ExtractionAttachmentsProgress);
+  },
+});

base_folder/src/functions/extraction/workers/data-extraction.ts

@@ -0,0 +1,9 @@
+import { ExtractorEventType, processTask } from "@devrev/ts-adaas";
+import { ExtractorState } from "../index";
+
+processTask<ExtractorState>({
+  task: async ({ adapter }) => {},
+  onTimeout: async ({ adapter }) => {
+    await adapter.emit(ExtractorEventType.ExtractionDataProgress);
+  },
+});

base_folder/src/functions/extraction/workers/external-sync-units-extraction.ts

@@ -0,0 +1,13 @@
+import { ExtractorEventType, processTask } from "@devrev/ts-adaas";
+import { ExtractorState } from "../index";
+
+processTask<ExtractorState>({
+  task: async ({ adapter }) => {},
+  onTimeout: async ({ adapter }) => {
+    await adapter.emit(ExtractorEventType.ExtractionExternalSyncUnitsError, {
+      error: {
+        message: 'Failed to extract external sync units. Lambda timeout.',
+      },
+    });
+  },
+});

base_folder/src/functions/extraction/workers/metadata-extraction.ts

@@ -0,0 +1,11 @@
+import { processTask, ExtractorEventType } from '@devrev/ts-adaas';
+import { ExtractorState } from '../index';
+  
+processTask<ExtractorState>({
+  task: async ({ adapter }) => {},
+  onTimeout: async ({ adapter }) => {
+    await adapter.emit(ExtractorEventType.ExtractionMetadataError, {
+      error: { message: 'Failed to extract metadata. Lambda timeout.' },
+    });
+  },
+});