feat: add support to per-function configuration files

src/config.ts

@@ -1,11 +1,15 @@
+import { promises as fs } from 'fs'
+import { basename, extname, dirname, join } from 'path'
+
 import mergeOptions from 'merge-options'
 
+import type { FeatureFlags } from './feature_flags.js'
 import { FunctionSource } from './function.js'
 import type { NodeBundlerName } from './runtimes/node/bundlers/types.js'
 import type { NodeVersionString } from './runtimes/node/index.js'
 import { minimatch } from './utils/matching.js'
 
-export interface FunctionConfig {
+interface FunctionConfig {
   externalNodeModules?: string[]
   includedFiles?: string[]
   includedFilesBasePath?: string
@@ -19,16 +23,54 @@ export interface FunctionConfig {
   zipGo?: boolean
 }
 
+interface FunctionConfigFile {
+  config: FunctionConfig
+  version: number
+}
+
 type GlobPattern = string
 
-export type Config = Record<GlobPattern, FunctionConfig>
+type Config = Record<GlobPattern, FunctionConfig>
+type FunctionWithoutConfig = Omit<FunctionSource, 'config'>
+
+const getConfigForFunction = async ({
+  config,
+  configFileDirectories,
+  func,
+  featureFlags,
+}: {
+  config?: Config
+  configFileDirectories?: string[]
+  func: FunctionWithoutConfig
+  featureFlags: FeatureFlags
+}): Promise<FunctionConfig> => {
+  const fromConfig = getFromMainConfig({ config, func })
+
+  // We try to read from a function config file if the function directory is
+  // inside one of `configFileDirectories`.
+  const shouldReadConfigFile =
+    featureFlags.project_deploy_configuration_api_use_per_function_configuration_files &&
+    configFileDirectories?.some((directory) => func.srcDir.startsWith(directory))
+
+  if (!shouldReadConfigFile) {
+    return fromConfig
+  }
+
+  const fromFile = await getFromFile(func)
+
+  return {
+    ...fromConfig,
+    ...fromFile,
+  }
+}
 
-export const getConfigForFunction = ({
+const getFromMainConfig = ({
   config,
   func,
 }: {
   config?: Config
-  func: Omit<FunctionSource, 'config'>
+  configFileDirectories?: string[]
+  func: FunctionWithoutConfig
 }): FunctionConfig => {
   if (!config) {
     return {}
@@ -56,3 +98,23 @@ export const getConfigForFunction = ({
 
   return mergeOptions.apply({ concatArrays: true, ignoreUndefined: true }, matches)
 }
+
+const getFromFile = async (func: FunctionWithoutConfig): Promise<FunctionConfig> => {
+  const filename = `${basename(func.mainFile, extname(func.mainFile))}.json`
+  const configFilePath = join(dirname(func.mainFile), filename)
+
+  try {
+    const data = await fs.readFile(configFilePath, 'utf8')
+    const configFile = JSON.parse(data) as FunctionConfigFile
+
+    if (configFile.version === 1) {
+      return configFile.config
+    }
+  } catch {
+    // no-op
+  }
+
+  return {}
+}
+
+export { Config, FunctionConfig, FunctionWithoutConfig, getConfigForFunction }

src/feature_flags.ts

@@ -5,6 +5,7 @@ export const defaultFlags: Record<string, boolean> = {
   parseWithEsbuild: false,
   traceWithNft: false,
   zisi_pure_esm: false,
+  project_deploy_configuration_api_use_per_function_configuration_files: false,
 }
 
 export type FeatureFlag = keyof typeof defaultFlags

src/runtimes/index.ts

@@ -1,6 +1,6 @@
 import { extname, basename } from 'path'
 
-import { Config, getConfigForFunction } from '../config.js'
+import { Config, getConfigForFunction, FunctionWithoutConfig } from '../config.js'
 import { defaultFlags, FeatureFlags } from '../feature_flags.js'
 import { FunctionSource } from '../function.js'
 import { FsCache } from '../utils/fs.js'
@@ -18,7 +18,7 @@ type FunctionMap = Map<string, FunctionSource>
 type FunctionTuple = [string, FunctionSource]
 
 // The same as `FunctionTuple` but functions don't have a `config` object yet.
-type FunctionTupleWithoutConfig = [string, Omit<FunctionSource, 'config'>]
+type FunctionTupleWithoutConfig = [string, FunctionWithoutConfig]
 
 /**
  * Finds functions for a list of paths using a specific runtime. The return
@@ -79,9 +79,10 @@ export const getFunctionsFromPaths = async (
   paths: string[],
   {
     config,
+    configFileDirectories = [],
     dedupe = false,
     featureFlags = defaultFlags,
-  }: { config?: Config; dedupe?: boolean; featureFlags?: FeatureFlags } = {},
+  }: { config?: Config; configFileDirectories?: string[]; dedupe?: boolean; featureFlags?: FeatureFlags } = {},
 ): Promise<FunctionMap> => {
   const fsCache = makeFsCache()
 
@@ -104,9 +105,12 @@ export const getFunctionsFromPaths = async (
       remainingPaths: runtimePaths,
     }
   }, Promise.resolve({ functions: [], remainingPaths: paths } as { functions: FunctionTupleWithoutConfig[]; remainingPaths: string[] }))
-  const functionsWithConfig: FunctionTuple[] = functions.map(([name, func]) => [
+  const functionConfigs = await Promise.all(
+    functions.map(([, func]) => getConfigForFunction({ config, configFileDirectories, func, featureFlags })),
+  )
+  const functionsWithConfig: FunctionTuple[] = functions.map(([name, func], index) => [
     name,
-    { ...func, config: getConfigForFunction({ config, func }) },
+    { ...func, config: functionConfigs[index] },
   ])
 
   return new Map(functionsWithConfig)
@@ -125,10 +129,12 @@ export const getFunctionFromPath = async (
     const func = await runtime.findFunctionInPath({ path, fsCache, featureFlags })
 
     if (func) {
+      const functionConfig = await getConfigForFunction({ config, func: { ...func, runtime }, featureFlags })
+
       return {
         ...func,
         runtime,
-        config: getConfigForFunction({ config, func: { ...func, runtime } }),
+        config: functionConfig,
       }
     }
   }

src/zip.ts

@@ -24,6 +24,7 @@ interface ZipFunctionOptions {
 }
 
 type ZipFunctionsOptions = ZipFunctionOptions & {
+  configFileDirectories?: string[]
   manifest?: string
   parallelLimit?: number
 }
@@ -46,6 +47,7 @@ export const zipFunctions = async function (
     archiveFormat = 'zip',
     basePath,
     config = {},
+    configFileDirectories,
     featureFlags: inputFeatureFlags,
     manifest,
     parallelLimit = DEFAULT_PARALLEL_LIMIT,
@@ -57,7 +59,7 @@ export const zipFunctions = async function (
   const featureFlags = getFlags(inputFeatureFlags)
   const srcFolders = resolveFunctionsDirectories(relativeSrcFolders)
   const [paths] = await Promise.all([listFunctionsDirectories(srcFolders), fs.mkdir(destFolder, { recursive: true })])
-  const functions = await getFunctionsFromPaths(paths, { config, dedupe: true, featureFlags })
+  const functions = await getFunctionsFromPaths(paths, { config, configFileDirectories, dedupe: true, featureFlags })
   const results = await pMap(
     functions.values(),
     async (func) => {

tests/fixtures/config-files-invalid-version/my-function-1/my-function-1.js

@@ -0,0 +1 @@
+export const handler = () => true

tests/fixtures/config-files-invalid-version/my-function-1/my-function-1.json

@@ -0,0 +1,5 @@
+{
+  "config": {
+    "includedFiles": ["blog/*.md"]
+  }
+}

tests/fixtures/config-files-invalid-version/my-function-2.js

@@ -0,0 +1 @@
+export const handler = () => true

tests/fixtures/config-files-invalid-version/my-function-2.json

@@ -0,0 +1,6 @@
+{
+  "config": {
+    "includedFiles": ["blog/*.md"]
+  },
+  "version": 3
+}

tests/fixtures/config-files-malformed-json/my-function-1/my-function-1.js

@@ -0,0 +1 @@
+export const handler = () => true

tests/fixtures/config-files-malformed-json/my-function-1/my-function-1.malformed-json

@@ -0,0 +1,2 @@
+{
+  "config": {

tests/fixtures/config-files-malformed-json/my-function-2.js

@@ -0,0 +1 @@
+export const handler = () => true

tests/fixtures/config-files-malformed-json/my-function-2.malformed-json

@@ -0,0 +1,6 @@
+{
+  "config": {
+    "includedFiles": ["blog/*.md"]
+  }
+  "version": 3
+}

tests/fixtures/config-files-select-directories/.netlify/functions-internal/internal-function/internal-function.js

@@ -0,0 +1 @@
+export const handler = () => true

tests/fixtures/config-files-select-directories/.netlify/functions-internal/internal-function/internal-function.json

@@ -0,0 +1,6 @@
+{
+  "config": {
+    "includedFiles": ["blog/*.md"]
+  },
+  "version": 1
+}

tests/fixtures/config-files-select-directories/netlify/functions/user-function/user-function.js

@@ -0,0 +1 @@
+export const handler = () => true

tests/fixtures/config-files-select-directories/netlify/functions/user-function/user-function.json

@@ -0,0 +1,6 @@
+{
+  "config": {
+    "includedFiles": ["blog/*.md"]
+  },
+  "version": 1
+}

tests/main.js

@@ -60,10 +60,32 @@ const getZipChecksum = async function (t, bundler) {
   return sha1sum
 }
 
+test.before(async () => {
+  // Renaming malformed `.malformed-json` files to `.json`
+  await rename(
+    join(FIXTURES_DIR, 'config-files-malformed-json', 'my-function-1', 'my-function-1.malformed-json'),
+    join(FIXTURES_DIR, 'config-files-malformed-json', 'my-function-1', 'my-function-1.json'),
+  )
+  await rename(
+    join(FIXTURES_DIR, 'config-files-malformed-json', 'my-function-2.malformed-json'),
+    join(FIXTURES_DIR, 'config-files-malformed-json', 'my-function-2.json'),
+  )
+})
+
 test.after.always(async () => {
   if (env.ZISI_KEEP_TEMP_DIRS === undefined) {
     await del(`${tmpdir()}/zip-it-test-bundler-*`, { force: true })
   }
+
+  // Renaming malformed `.json` files back to `.malformed-json`
+  await rename(
+    join(FIXTURES_DIR, 'config-files-malformed-json', 'my-function-1', 'my-function-1.json'),
+    join(FIXTURES_DIR, 'config-files-malformed-json', 'my-function-1', 'my-function-1.malformed-json'),
+  )
+  await rename(
+    join(FIXTURES_DIR, 'config-files-malformed-json', 'my-function-2.json'),
+    join(FIXTURES_DIR, 'config-files-malformed-json', 'my-function-2.malformed-json'),
+  )
 })
 
 test.afterEach(() => {
@@ -2758,3 +2780,109 @@ test('listFunctionsFiles does not include wrong arch functions and warns', async
 
   console.warn.restore()
 })
+
+testMany(
+  'Loads function configuration properties from a JSON file if the function is inside one of `configFileDirectories`',
+  ['bundler_nft', 'bundler_esbuild', 'bundler_default'],
+  async (options, t) => {
+    const fixtureName = 'config-files-select-directories'
+    const pathInternal = join(fixtureName, '.netlify', 'functions-internal')
+    const pathUser = join(fixtureName, 'netlify', 'functions')
+    const opts = merge(options, {
+      basePath: join(FIXTURES_DIR, fixtureName),
+      configFileDirectories: [join(FIXTURES_DIR, pathInternal)],
+      featureFlags: { project_deploy_configuration_api_use_per_function_configuration_files: true },
+    })
+    const { files, tmpDir } = await zipFixture(t, [pathInternal, pathUser], {
+      length: 2,
+      opts,
+    })
+
+    const func1Entry = files.find(({ name }) => name === 'internal-function')
+    const func2Entry = files.find(({ name }) => name === 'user-function')
+
+    t.deepEqual(func1Entry.config.includedFiles, ['blog/*.md'])
+    t.is(func2Entry.config.includedFiles, undefined)
+
+    await unzipFiles(files, (path) => `${path}/../${basename(path)}_out`)
+
+    const functionPaths = [
+      join(tmpDir, 'internal-function.zip_out', 'internal-function.js'),
+      join(tmpDir, 'user-function.zip_out', 'user-function.js'),
+    ]
+    const func1 = await importFunctionFile(functionPaths[0])
+    const func2 = await importFunctionFile(functionPaths[1])
+
+    t.true(func1.handler())
+    t.true(func2.handler())
+
+    t.true(await pathExists(`${tmpDir}/internal-function.zip_out/blog/one.md`))
+    t.false(await pathExists(`${tmpDir}/user-function.zip_out/blog/one.md`))
+  },
+)
+
+testMany(
+  'Ignores function configuration files with a missing or invalid `version` property',
+  ['bundler_nft', 'bundler_esbuild', 'bundler_default'],
+  async (options, t) => {
+    const fixtureName = 'config-files-invalid-version'
+    const fixtureDir = join(FIXTURES_DIR, fixtureName)
+    const opts = merge(options, {
+      basePath: fixtureDir,
+      configFileDirectories: [fixtureDir],
+      featureFlags: { zisi_detect_esm: true },
+    })
+    const { files, tmpDir } = await zipFixture(t, fixtureName, {
+      length: 2,
+      opts,
+    })
+
+    await unzipFiles(files, (path) => `${path}/../${basename(path)}_out`)
+
+    const functionPaths = [
+      join(tmpDir, 'my-function-1.zip_out', 'my-function-1.js'),
+      join(tmpDir, 'my-function-2.zip_out', 'my-function-2.js'),
+    ]
+    const func1 = await importFunctionFile(functionPaths[0])
+    const func2 = await importFunctionFile(functionPaths[1])
+
+    t.true(func1.handler())
+    t.true(func2.handler())
+    t.is(files[0].config.includedFiles, undefined)
+    t.is(files[1].config.includedFiles, undefined)
+    t.false(await pathExists(`${tmpDir}/my-function-1.zip_out/blog/one.md`))
+  },
+)
+
+testMany(
+  'Ignores function configuration files with malformed JSON',
+  ['bundler_nft', 'bundler_esbuild', 'bundler_default'],
+  async (options, t) => {
+    const fixtureName = 'config-files-malformed-json'
+    const fixtureDir = join(FIXTURES_DIR, fixtureName)
+    const opts = merge(options, {
+      basePath: fixtureDir,
+      configFileDirectories: [fixtureDir],
+      featureFlags: { zisi_detect_esm: true },
+    })
+    const { files, tmpDir } = await zipFixture(t, fixtureName, {
+      length: 2,
+      opts,
+    })
+
+    await unzipFiles(files, (path) => `${path}/../${basename(path)}_out`)
+
+    const functionPaths = [
+      join(tmpDir, 'my-function-1.zip_out', 'my-function-1.js'),
+      join(tmpDir, 'my-function-2.zip_out', 'my-function-2.js'),
+    ]
+    const func1 = await importFunctionFile(functionPaths[0])
+    const func2 = await importFunctionFile(functionPaths[1])
+
+    t.true(func1.handler())
+    t.true(func2.handler())
+    t.is(files[0].config.includedFiles, undefined)
+    t.is(files[1].config.includedFiles, undefined)
+    t.false(await pathExists(`${tmpDir}/my-function-1.zip_out/blog/one.md`))
+  },
+)