feat: pull DB migrations (#8139)

Author: paulo

src/commands/database/database.ts

@@ -3,6 +3,7 @@ import inquirer from 'inquirer'
 import BaseCommand from '../base-command.js'
 import type { DatabaseBoilerplateType, DatabaseInitOptions } from './init.js'
 import type { MigrationNewOptions } from './migration-new.js'
+import type { MigrationPullOptions } from './migration-pull.js'
 
 export type Extension = {
   id: string
@@ -31,7 +32,7 @@ export const createDatabaseCommand = (program: BaseCommand) => {
     .addExamples([
       'netlify db status',
       ...(process.env.EXPERIMENTAL_NETLIFY_DB_ENABLED === '1'
-        ? ['netlify db migrations apply', 'netlify db reset', 'netlify db migrations new']
+        ? ['netlify db migrations apply', 'netlify db migrations pull', 'netlify db reset', 'netlify db migrations new']
         : ['netlify db init', 'netlify db init --help']),
     ])
 
@@ -149,5 +150,25 @@ export const createDatabaseCommand = (program: BaseCommand) => {
         'netlify db migrations new',
         'netlify db migrations new --description "add users table" --scheme sequential',
       ])
+
+    migrationsCommand
+      .command('pull')
+      .description('Pull migrations and overwrite local migration files')
+      .option(
+        '-b, --branch [branch]',
+        "Pull migrations for a specific branch (defaults to 'production'; pass --branch with no value to use local git branch)",
+      )
+      .option('--force', 'Skip confirmation prompt', false)
+      .option('--json', 'Output result as JSON')
+      .action(async (options: MigrationPullOptions, command: BaseCommand) => {
+        const { migrationPull } = await import('./migration-pull.js')
+        await migrationPull(options, command)
+      })
+      .addExamples([
+        'netlify db migrations pull',
+        'netlify db migrations pull --branch staging',
+        'netlify db migrations pull --branch',
+        'netlify db migrations pull --force',
+      ])
   }
 }

src/commands/database/migration-pull.ts

@@ -0,0 +1,147 @@
+import { rm, mkdir, writeFile } from 'fs/promises'
+import { dirname, resolve, isAbsolute } from 'path'
+
+import inquirer from 'inquirer'
+
+import { log, logJson } from '../../utils/command-helpers.js'
+import execa from '../../utils/execa.js'
+import BaseCommand from '../base-command.js'
+import { resolveMigrationsDirectory } from './migration-new.js'
+
+export interface MigrationPullOptions {
+  branch?: string | true
+  force?: boolean
+  json?: boolean
+}
+
+interface MigrationFile {
+  version: number
+  name: string
+  path: string
+  content: string
+}
+
+interface ListMigrationsResponse {
+  migrations: MigrationFile[]
+}
+
+const getLocalGitBranch = async (): Promise<string> => {
+  const { stdout } = await execa('git', ['rev-parse', '--abbrev-ref', 'HEAD'])
+  const branch = stdout.trim()
+  if (!branch || branch === 'HEAD') {
+    throw new Error('Could not determine the current git branch. Are you in a detached HEAD state?')
+  }
+  return branch
+}
+
+const resolveBranch = async (branchOption: string | true | undefined): Promise<string | undefined> => {
+  if (branchOption === undefined) {
+    return undefined
+  }
+  if (branchOption === true) {
+    return getLocalGitBranch()
+  }
+  return branchOption
+}
+
+const fetchMigrations = async (command: BaseCommand, branch: string | undefined): Promise<MigrationFile[]> => {
+  const siteId = command.siteId
+  if (!siteId) {
+    throw new Error('The project must be linked with netlify link before pulling migrations.')
+  }
+
+  const accessToken = command.netlify.api.accessToken
+  if (!accessToken) {
+    throw new Error('You must be logged in with netlify login to pull migrations.')
+  }
+
+  const token = accessToken.replace('Bearer ', '')
+  const basePath = command.netlify.api.basePath
+
+  const url = new URL(`${basePath}/sites/${encodeURIComponent(siteId)}/database/migrations`)
+  if (branch) {
+    url.searchParams.set('branch', branch)
+  }
+
+  const response = await fetch(url, {
+    headers: {
+      Authorization: `Bearer ${token}`,
+    },
+  })
+
+  if (!response.ok) {
+    const text = await response.text()
+    throw new Error(`Failed to fetch migrations (${String(response.status)}): ${text}`)
+  }
+
+  const data = (await response.json()) as ListMigrationsResponse
+  return data.migrations
+}
+
+export const migrationPull = async (options: MigrationPullOptions, command: BaseCommand) => {
+  const { force, json } = options
+
+  const branch = await resolveBranch(options.branch)
+  const source = branch ?? 'production'
+  const migrations = await fetchMigrations(command, branch)
+
+  if (migrations.length === 0) {
+    if (json) {
+      logJson({ migrations_pulled: 0, branch: source })
+    } else {
+      log(`No migrations found for ${source}.`)
+    }
+    return
+  }
+
+  const migrationsDirectory = resolveMigrationsDirectory(command)
+
+  if (!force) {
+    const { confirmed } = await inquirer.prompt<{ confirmed: boolean }>([
+      {
+        type: 'confirm',
+        name: 'confirmed',
+        message: `This will overwrite all local migrations in ${migrationsDirectory} with ${String(
+          migrations.length,
+        )} migration${migrations.length === 1 ? '' : 's'} from ${source}. Continue?`,
+        default: false,
+      },
+    ])
+
+    if (!confirmed) {
+      log('Pull cancelled.')
+      return
+    }
+  }
+
+  const canonicalMigrationsDir = resolve(migrationsDirectory)
+
+  await rm(canonicalMigrationsDir, { recursive: true, force: true })
+
+  for (const migration of migrations) {
+    if (isAbsolute(migration.path) || migration.path.split(/[/\\]/).includes('..')) {
+      throw new Error(`Migration path "${migration.path}" contains invalid path segments.`)
+    }
+
+    const filePath = resolve(canonicalMigrationsDir, migration.path)
+    if (!filePath.startsWith(canonicalMigrationsDir)) {
+      throw new Error(`Migration path "${migration.path}" resolves outside the migrations directory.`)
+    }
+
+    await mkdir(dirname(filePath), { recursive: true })
+    await writeFile(filePath, migration.content)
+  }
+
+  if (json) {
+    logJson({
+      migrations_pulled: migrations.length,
+      branch: source,
+      migrations: migrations.map((m) => m.name),
+    })
+  } else {
+    log(`Pulled ${String(migrations.length)} migration${migrations.length === 1 ? '' : 's'} from ${source}:`)
+    for (const migration of migrations) {
+      log(`  - ${migration.name}`)
+    }
+  }
+}