hammer

README

hammer

hammer is a command-line tool to schema management for Google Cloud Spanner.

Installation

Download the single-binary executable from:

https://github.com/daichirata/hammer/releases

or

$ go get -u github.com/daichirata/hammer

Useage

hammer is a command-line tool to schema management for Google Cloud Spanner.

Usage:
  hammer DATABASE SOURCE [flags]
  hammer [command]

Available Commands:
  diff        Diff schema
  export      Export schema
  help        Help about any command

Flags:
  -h, --help   help for hammer

Use "hammer [command] --help" for more information about a command.

Examples:

* Export spanner schema
  hammer export spanner://projects/projectId/instances/instanceId/databases/databaseName > schema.sql

* Apply local schema file
  hammer spanner://projects/projectId/instances/instanceId/databases/databaseName /path/to/file.sql

* Compare local files
  hammer diff /path/to/file /another/path/to/file

* Compare local file against spanner schema
  hammer diff /path/to/file spanner://projects/projectId/instances/instanceId/databases/databaseName

* Compare spanner schema against spanner schema
  hammer diff spanner://projects/projectId/instances/instanceId/databases/databaseName1 spanner://projects/projectId/instances/instanceId/databases/databaseName2

The DSN must be given in the following format.

spanner://projects/{projectId}/instances/{instanceId}/databases/{databaseName}?credentials=/path/to/file.json

Param	Description
credentials	The path to the keyfile. If not present, client will use your default application credentials.
projectId	The Google Cloud Platform project id
instanceId	The id of the instance running Spanner
databaseName	The name of the Spanner database

Examples

Suppose you have an existing SQL schema like the following:

CREATE TABLE users (
  user_id STRING(36) NOT NULL,
) PRIMARY KEY(user_id);

And you want "upgrade" your schema to the following:

CREATE TABLE users (
  user_id STRING(36) NOT NULL,
  age INT64,
  name STRING(MAX) NOT NULL,
) PRIMARY KEY(user_id);
CREATE INDEX idx_users_name ON users (name);

Hammer changes the schema by applying the following SQL to the spanner:

hammer diff old.sql new.sql

ALTER TABLE users ADD COLUMN age INT64
ALTER TABLE users ADD COLUMN name STRING(MAX)
UPDATE users SET name = '' WHERE name IS NULL
ALTER TABLE users ALTER COLUMN name STRING(MAX) NOT NULL
CREATE INDEX idx_users_name ON users(name)

When adding a column with the NOT NULL attribute, update the default value after adding the column once, and then add the NOT NULL attribute.

LICENSE

Unless otherwise noted, the hammer source files are distributed under the MIT License found in the LICENSE file.