Refactor scheduled circulars Lambda

I'm preparing to add yet a third action to generate sitemap files.
To keep everything nice and neat, here are a few refactorings:

- Collect all of the actions into the actions/ directory.
- Factor out repeated S3 bucket config details into a common file.
- Collect the mapCirculars function and the CircularsAction type
  into one file to keep the Lambda entry point itself clean as
  we add more imports for the actions.
- Rename the mapCirculars function to forAllCirculars, because its
  behavior more closely resembles the .forEach() array method than
  the .map() method.

app/routes/circulars.archive[.]json[.]tar[.]gz.ts

@@ -8,7 +8,7 @@
 import { redirect } from '@remix-run/node'
 
 import { publicStaticShortTermCacheControlHeaders } from '~/lib/headers.server'
-import { getArchiveURL } from '~/scheduled/circulars/uploadTar'
+import { getArchiveURL } from '~/scheduled/circulars/actions/tar'
 
 export function loader() {
   return redirect(getArchiveURL('json'), {

app/routes/circulars.archive[.]txt[.]tar[.]gz.ts

@@ -8,7 +8,7 @@
 import { redirect } from '@remix-run/node'
 
 import { publicStaticShortTermCacheControlHeaders } from '~/lib/headers.server'
-import { getArchiveURL } from '~/scheduled/circulars/uploadTar'
+import { getArchiveURL } from '~/scheduled/circulars/actions/tar'
 
 export function loader() {
   return redirect(getArchiveURL('txt'), {

app/scheduled/circulars/actions.ts

@@ -0,0 +1,41 @@
+/*!
+ * Copyright © 2023 United States Government as represented by the
+ * Administrator of the National Aeronautics and Space Administration.
+ * All Rights Reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+import { tables } from '@architect/functions'
+import type { DynamoDBDocument } from '@aws-sdk/lib-dynamodb'
+import { paginateScan } from '@aws-sdk/lib-dynamodb'
+
+import type { Circular } from '~/routes/circulars/circulars.lib'
+
+export interface CircularAction<T = any> {
+  initialize: () => T | Promise<T>
+  action: (circulars: Circular[], context: T) => void | Promise<void>
+  finalize: (context: T) => void | Promise<void>
+}
+
+export async function forAllCirculars(...actions: CircularAction[]) {
+  const contexts = await Promise.all(
+    actions.map((action) => action.initialize())
+  )
+  for await (const circulars of getAllRecords()) {
+    await Promise.all(
+      actions.map(({ action }, i) => action(circulars, contexts[i]))
+    )
+  }
+  await Promise.all(actions.map(({ finalize }, i) => finalize(contexts[i])))
+}
+
+async function* getAllRecords() {
+  const db = await tables()
+  const client = db._doc as unknown as DynamoDBDocument
+  const TableName = db.name('circulars')
+  const pages = paginateScan({ client }, { TableName })
+
+  for await (const page of pages) {
+    yield page.Items as Circular[]
+  }
+}

app/scheduled/circulars/stats.ts → app/scheduled/circulars/actions/stats.ts

@@ -5,13 +5,13 @@
  *
  * SPDX-License-Identifier: Apache-2.0
  */
-import { PutObjectCommand, S3Client } from '@aws-sdk/client-s3'
+import { PutObjectCommand } from '@aws-sdk/client-s3'
 
-import type { CircularAction } from './circularAction'
+import type { CircularAction } from '../actions'
+import { keyPrefix, s3 } from '../storage'
 import { staticBucket as Bucket } from '~/lib/env.server'
 
-const s3 = new S3Client({})
-const Key = 'generated/circulars/stats.json'
+const Key = `${keyPrefix}/stats.json`
 
 export const statsAction: CircularAction<Record<string, number>> = {
   initialize() {

app/scheduled/circulars/uploadTar.ts → app/scheduled/circulars/actions/tar.ts

@@ -5,27 +5,26 @@
  *
  * SPDX-License-Identifier: Apache-2.0
  */
-import { S3Client } from '@aws-sdk/client-s3'
 import { Upload } from '@aws-sdk/lib-storage'
 import { basename } from 'node:path'
 import { PassThrough } from 'node:stream'
 import { createGzip } from 'node:zlib'
 import type { Pack } from 'tar-stream'
 import { pack as tarPack } from 'tar-stream'
 
-import type { CircularAction } from './circularAction'
+import type { CircularAction } from '../actions'
+import { keyPrefix, s3 } from '../storage'
 import { staticBucket as Bucket, region } from '~/lib/env.server'
 import type { Circular } from '~/routes/circulars/circulars.lib'
 import {
   formatCircularJson,
   formatCircularText,
 } from '~/routes/circulars/circulars.lib'
 
-const s3 = new S3Client({})
 const archiveSuffix = '.tar.gz'
 
 function getBucketKey(suffix: string) {
-  return `generated/circulars/archive.${suffix}${archiveSuffix}`
+  return `${keyPrefix}/archive.${suffix}${archiveSuffix}`
 }
 
 function getBucketUrl(region: string, bucket: string, key: string) {

app/scheduled/circulars/index.ts

@@ -5,40 +5,12 @@
  *
  * SPDX-License-Identifier: Apache-2.0
  */
-import { tables } from '@architect/functions'
-import type { DynamoDBDocument } from '@aws-sdk/lib-dynamodb'
-import { paginateScan } from '@aws-sdk/lib-dynamodb'
-
-import type { CircularAction } from './circularAction'
-import { statsAction } from './stats'
-import { jsonUploadAction, txtUploadAction } from './uploadTar'
-import { type Circular } from '~/routes/circulars/circulars.lib'
-
-async function mapCirculars(...actions: CircularAction[]) {
-  const contexts = await Promise.all(
-    actions.map((action) => action.initialize())
-  )
-  for await (const circulars of getAllRecords()) {
-    await Promise.all(
-      actions.map(({ action }, i) => action(circulars, contexts[i]))
-    )
-  }
-  await Promise.all(actions.map(({ finalize }, i) => finalize(contexts[i])))
-}
-
-async function* getAllRecords() {
-  const db = await tables()
-  const client = db._doc as unknown as DynamoDBDocument
-  const TableName = db.name('circulars')
-  const pages = paginateScan({ client }, { TableName })
-
-  for await (const page of pages) {
-    yield page.Items as Circular[]
-  }
-}
+import { forAllCirculars } from './actions'
+import { statsAction } from './actions/stats'
+import { jsonUploadAction, txtUploadAction } from './actions/tar'
 
 // FIXME: must use module.exports here for OpenTelemetry shim to work correctly.
 // See https://dev.to/heymarkkop/how-to-solve-cannot-redefine-property-handler-on-aws-lambda-3j67
 module.exports.handler = async () => {
-  await mapCirculars(jsonUploadAction, txtUploadAction, statsAction)
+  await forAllCirculars(jsonUploadAction, txtUploadAction, statsAction)
 }

app/scheduled/circulars/storage.ts

@@ -0,0 +1,11 @@
+/*!
+ * Copyright © 2023 United States Government as represented by the
+ * Administrator of the National Aeronautics and Space Administration.
+ * All Rights Reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+import { S3Client } from '@aws-sdk/client-s3'
+
+export const s3 = new S3Client({})
+export const keyPrefix = 'generated/circulars'