A Leiningen plugin to validate that a database migrated by tern is at the expected schema version level for the library that uses it.

1. Put [cc.artifice/tern-validate "1.0.0"] into the :plugins vector of the project.clj file for the project that uses tern.
2. Install your project (lein install) or run under the repl (lein repl).
3. Call tern-validate.core/validate2, which will return true or false. The function takes a map as its sole parameter, with these keys
   • runtime-version -- The database schema version as a string (e.g., "20160825231113"). Typically, this would be the largest value in the 'versions' column of the table 'schema_versions" in your database. For example, if you are using Korma and have initialized the connection to the database, a simple query like this works: (:version (first (select :schema_versions (fields :version) (order :version :DESC) (limit 1))))
   • schema-project-name -- (optional) The name of a project associated with the database, and which typically is coupled to the schema version.
   • project -- (optional) A leiningen project map, which might contain a :tern entry (a map) with a :validation entry. If there is a :validation entry, it should be a map containing :min-version and/or :max-version values, as strings.
   • callback -- (optional) A function, which must accept a single argument, a map, that describes the validation status.

Out of the box, tern-validate will tell you if the running database exactly matches the version number of the latest migration in the migrations/ folder of the project that uses tern. You may add a :validation key to the tern configuration in project, which allows you to specify a range of versions that are acceptable to the library:

...
:tern {:migration-dir "migrations"
       :version-table "schema_versions"
       :validation {:min-version "20160627122211" :max-version "20160714092135"}}
...

If min or max version is missing, the acceptable version range is open-ended. If both are missing, the database version must exactly match the version of the latest migration.

At present, the migrations directory must be migrations/, directly under the project directory.

Copyright © 2016, 2017 i2k Connect LLC

Distributed under the Eclipse Public License version 1.0.