Drop database connection by default

When invoke drop database API or command, by default it will kill all active
connections before dropping db.

May opt out via `dropConnections: false` or `--no-dropConnections`

README.md

@@ -50,6 +50,7 @@ export type NewDbConfig = {
 export type DropDbConfig = {
   databaseName: string,
   errorIfNonExist?: boolean,
+  dropConnections?: boolean,
 }
 
 export type DbCredential = {
@@ -121,6 +122,7 @@ USAGE
 
 OPTIONS
   -e, --errorIfNonExist            [default: false] whether throw error if DB doesn't exist
+  -d, --dropConnections            [default: true] whether automatically drop DB connections
   -h, --help                       show CLI help
   -h, --host=host                  [default: localhost] DB host
   -i, --initialDb=initialDb        [default: postgres] Initial DB name
@@ -134,7 +136,7 @@ ALIASES
 
 EXAMPLES
   $ pg-god db-drop --databaseName=bank-db
-  $ pg-god db-drop --databaseName=bank-db --errorIfNonExist
+  $ pg-god db-drop --databaseName=bank-db --errorIfNonExist --no-dropConnections
   $ pg-god db-drop --databaseName=bank-db --password=123 --port=5433 --host=a.example.com --userName=beer
 ```
 

package.json

@@ -1,7 +1,7 @@
 {
   "name": "pg-god",
   "description": "Tiny library that helps create and kill PostgreSQL database.",
-  "version": "1.0.5",
+  "version": "1.0.6",
   "author": "ivan.wang @ivawzh",
   "bin": {
     "pg-god": "./bin/run"

src/commands/db-create.ts

@@ -36,23 +36,19 @@ export default class DbCreate extends Command {
       }
     } = this.parse(DbCreate)
 
-    try {
-      cli.action.start(`😇 Start to create database '${databaseName}'`)
+    cli.action.start(`😇 Start to create database '${databaseName}'`)
 
-      createDatabase(
-        { databaseName, errorIfExist },
-        {
-          user: userName,
-          database: initialDb,
-          port: port,
-          host: host,
-          password: password,
-        }
-      )
+    await createDatabase(
+      { databaseName, errorIfExist },
+      {
+        user: userName,
+        database: initialDb,
+        port: port,
+        host: host,
+        password: password,
+      }
+    )
 
-      cli.action.stop()
-    } catch (error) {
-      console.error(error)
-    }
+    cli.action.stop()
   }
 }

src/commands/db-drop.ts

@@ -8,14 +8,15 @@ export default class DbDrop extends Command {
 
   static examples = [
     `$ pg-god db-drop --databaseName=bank-db`,
-    `$ pg-god db-drop --databaseName=bank-db --errorIfNonExist`,
+    `$ pg-god db-drop --databaseName=bank-db --errorIfNonExist --no-dropConnections`,
     `$ pg-god db-drop --databaseName=bank-db --password=123 --port=5433 --host=a.example.com --userName=beer`,
   ]
 
   static flags = {
     help: flags.help({char: 'h'}),
     databaseName: flags.string({char: 'n', required: true, description: 'name of DB attempt to drop', env: 'DB_NAME'}),
     errorIfNonExist: flags.boolean({char: 'e', default: false, description: "[default: false] whether throw error if DB doesn't exist", env: 'DB_ERROR_IF_NON_EXIST'}),
+    dropConnections: flags.boolean({char: 'd', default: true, allowNo: true, description: "[default: true] whether automatically drop DB connections"}),
     userName: flags.string({char: 'u', default: 'postgres', description: 'DB user name', env: 'DB_USERNAME'}),
     initialDb: flags.string({char: 'i', default: 'postgres', description: 'Initial DB name', env: 'DB_INITIAL'}),
     port: flags.integer({char: 'p', default: 5432, description: 'DB port, default `5432`', env: 'DB_PORT'}),
@@ -28,6 +29,7 @@ export default class DbDrop extends Command {
       flags: {
         databaseName,
         errorIfNonExist,
+        dropConnections,
         userName,
         initialDb,
         port,
@@ -36,23 +38,23 @@ export default class DbDrop extends Command {
       }
     } = this.parse(DbDrop)
 
-    try {
-      cli.action.start(`😇 Start to drop database '${databaseName}'`)
+    cli.action.start(`😇 Start to drop database '${databaseName}'`)
 
-      dropDatabase(
-        { databaseName, errorIfNonExist },
-        {
-          user: userName,
-          database: initialDb,
-          port: port,
-          host: host,
-          password: password,
-        }
-      )
+    await dropDatabase(
+      {
+        databaseName,
+        errorIfNonExist,
+        dropConnections,
+      },
+      {
+        user: userName,
+        database: initialDb,
+        port: port,
+        host: host,
+        password: password,
+      }
+    )
 
-      cli.action.stop()
-    } catch (error) {
-      console.error(error)
-    }
+    cli.action.stop()
   }
 }

src/god-stuff.ts

@@ -57,10 +57,12 @@ export async function createDatabase(newDbConfig: NewDbConfig, dbCredential: Par
 export type DropDbConfig = {
   databaseName: string,
   errorIfNonExist?: boolean,
+  dropConnections?: boolean,
 }
 /**
- * @param dropDbConfig Requires a `databaseName` you are trying to drop. `errorIfNonExist` is default to false. When `errorIfNonExist` is `true`,
- * it will throw error when database doesn't exist before executing drop.
+ * @param dropDbConfig.databaseName Requires a `databaseName` you are trying to drop.
+ * @param dropDbConfig.errorIfNonExist is default to false. When `errorIfNonExist` is `true`, it will throw error when database doesn't exist before executing drop.
+ * @param dropDbConfig.dropConnections is default to true. When `dropConnections` is `true`, it will automatically drop all current connections to the database.
  * @param dbCredential Default to localhost:5432 `postgres` database and `postgres` user with empty password.
  * @throws `PgDbGodError` More details at `errorProtocol`.
  *
@@ -81,10 +83,24 @@ export async function dropDatabase(dropDbConfig: DropDbConfig, dbCredential: DbC
     if (existingDb.rowCount === 0 && dropDbConfig.errorIfNonExist) throw PgGodError.dbDoesNotExist()
     if (existingDb.rowCount === 0 && !dropDbConfig.errorIfNonExist) return
 
+    if (dropDbConfig.dropConnections !== false) await dropDbConnections(client, dropDbConfig.databaseName)
+
     await client.query(`DROP DATABASE "${dropDbConfig.databaseName}";`)
   } catch (error) {
     throw PgGodError.fromPgError(error)
   } finally {
     await client.end()
   }
 }
+
+async function dropDbConnections(client: Client, dbName: string) {
+  return client.query(`
+    SELECT
+      pg_terminate_backend(pg_stat_activity.pid)
+    FROM
+      pg_stat_activity
+    WHERE
+      pg_stat_activity.datname = '${dbName}'
+      AND pid <> pg_backend_pid();
+  `)
+}