single and dry run

src/cli.ts

@@ -10,11 +10,12 @@ program.version(spec.version).name(spec.name)
 program
   .command('migrate')
   .description('run migrations')
-  // .option('--dry-run', 'run simulation without committing changes')
+  .option('--dry-run', 'run simulation without committing changes')
   .option('-m, --migrations <glob>', 'migration files', './migrations/*.js')
-  .option('--force', 'ignore remote state and rerun migrations')
+  .option('--only <version...>', 'only run specific migration')
+  .option('-f, --force', 'ignore remote state and rerun migrations')
   .action(async (args) => {
-    await migrate({ directory: args.migrations, ignoreRemote: args.force })
+    await migrate({ directory: args.migrations, ignoreRemote: args.force, single: args.only, dryRun: args.dryRun })
   })
 
 program.parse(process.argv)

src/index.ts

@@ -32,16 +32,23 @@ export type Options = {
   directory: string
   delimiter: string
   ignoreRemote: boolean
+  single?: string[]
+  dryRun: boolean
 }
 
 const defaults: Options = {
   directory: './migrations',
   delimiter: '__',
   ignoreRemote: false,
+  dryRun: false,
 }
 
 const extension = /\..*$/
 
+function sortMigrationFiles(arr: MigrationFile[]): MigrationFile[] {
+  return arr.sort((a, b) => (semver.gt(a.version, b.version) ? 1 : -1))
+}
+
 async function gather(options: Options): Promise<MigrationFile[]> {
   const files = glob
     .sync(path.join(options.directory, '*.js'))
@@ -68,11 +75,11 @@ async function gather(options: Options): Promise<MigrationFile[]> {
     })
   )
 
-  const sorted = contents.sort((a, b) => (semver.gt(a.version, b.version) ? 1 : -1))
+  const asMigrationFile = contents.map(({ version, ...rest }) => ({
-  return sorted.map(({ version, ...rest }) => ({
     ...rest,
     version: version.version,
   }))
+  return sortMigrationFiles(asMigrationFile)
 }
 
 function getIdFromMigration(migration: MigrationFile): string {
@@ -93,6 +100,11 @@ async function runMigrations(migrations: MigrationFile[], options: Options) {
       continue
     }
 
+    if (options.dryRun) {
+      printMigration(migration, 'Skip due to dry-run.')
+      return
+    }
+
     const start = process.hrtime.bigint()
     let error = false
     try {
@@ -115,15 +127,34 @@ async function runMigrations(migrations: MigrationFile[], options: Options) {
       await remoteDoc.ref.set(result)
 
       if (error) {
-        console.log('⚠️ Skipping next migrations')
+        throw new Error('⚠️ Skipping next migrations')
-        break
       }
     }
   }
 }
 
 export async function migrate(options?: Partial<Options>) {
+  try {
     const merged: Options = Object.assign(defaults, options)
-  const migrations = await gather(merged)
+    let migrations = await gather(merged)
+    console.log(`Found ${chalk.bold(migrations.length)} migrations.`)
+    if (options?.single) {
+      const singleVersions = options.single.map((v) => {
+        const parsed = semver.coerce(v)
+        if (!parsed) throw new Error(`Invalid version specified: "${v}". Could not parse.`)
+        return parsed.version
+      })
+      const filtered = singleVersions.map((v) => {
+        const selected = migrations.find((m) => m.version === v)
+        if (!selected) throw new Error(`Version "${v}" specified in --only does not exist in as migration.`)
+        return selected
+      })
+      migrations = sortMigrationFiles(filtered)
+      console.log(`Only running specified versions: ${singleVersions.join(', ')}`)
+    }
     await runMigrations(migrations, merged)
+  } catch (e) {
+    console.error(chalk.red(e.message))
+    process.exit(1)
+  }
 }