README.md

spanner-emulator-init

You're using the spanner emulator and want to have some automated spin up of one or multiple databases? If so, this docker-compose contains your solution!

Goal

Spanner emulator can be spinned up with multiple commands. Goal of this docker image is to automate these calls and have one single configuration for spinning up a spanner emulator instance containing as many databases with as many tables / dml-scripts as the developer wants to have.

Configuration

A folder is mounted into the docker image. Within this folder, there can be one or multiple sub-directories. Each of them represents a dedicated database (folder-name = database-name).

Within a database-folder, ddl- and dml-folders are used for updating the database and executing the sql.

Example usage

An example usage can be found with docker-compose.yaml. The emulator itself need to be spinned up as a separate service (spanner-emulator). The initializer is dependent on this service, and requires following environment arguments:

• INIT_DIR: directory, in which the databases are located.
• INSTANCE_NAME: name of the instance
• PROJECT_ID: id of the google project
• SPANNER_EMULATOR_URL: referring to the spanner-emulator-service-name

Next to the environment variables, the right directory need to be mounted into the docker image, so that the script is able to recognize databases.

Folder-/ file-structure

Here's an example of the structure of spinning up multiple databases with different setups:

init-scripts
│
├── database1
│   │
│   ├── ddl
│   │   │   table1.sql
│   │   │   table2.sql
│   │   │   ...
│   ├── dml
│   │   │   table1.sql
│   │   │   table2.sql
│   │   │   ...
├── database2
│   │
│   ├── ddl
│   │   │   table3.sql
│   │   │   table4.sql
│   │   │   ...
│   ├── dml
│   │   │   table3.sql
│   │   │   table4.sql
│   │   │   ...
└── ...
│   │
│   ├── ddl
│   │   │   ...
│   ├── dml
│   │   │   ...