Migrating to sqlc-gen-kotlin

Starting in sqlc 1.16.0, built-in Kotlin support has been deprecated. It will be fully removed in 1.17.0 in favor of sqlc-gen-kotlin.

This guide will walk you through migrating to the sqlc-gen-kotlin plugin, which involves three steps.

1. Add the sqlc-gen-kotlin plugin

2. Migrate each package

3. Re-generate the code

Add the sqlc-gen-kotlin plugin

In your configuration file, add a plugins array if you don’t have one already. Add the following configuration for the plugin:

{
  "version": "2",
  "plugins": [
    {
      "name": "kt",
      "wasm": {
        "url": "https://downloads.sqlc.dev/plugin/sqlc-gen-kotlin_1.0.0.wasm",
        "sha256": "7620dc5d462de41fdc90e2011232c842117b416c98fd5c163d27c5738431a45c"
      }
    }
  ]
}

version: "2"
plugins:
- name: "kt"
  wasm:
    url: "https://downloads.sqlc.dev/plugin/sqlc-gen-kotlin_1.0.0.wasm"
    sha256: "7620dc5d462de41fdc90e2011232c842117b416c98fd5c163d27c5738431a45c"

Migrate each package

Your package configuration should currently looks something like this for JSON.

  "sql": [
    {
      "schema": "schema.sql",
      "queries": "query.sql",
      "engine": "postgresql",
      "gen": {
        "kotlin": {
          "out": "src/main/kotlin/com/example/foo",
          "package": "com.example.foo"
        }
      }
    }
  ]

Or this if you’re using YAML.

  sql:
  - schema: "schema.sql"
    queries: "query.sql"
    engine: "postgresql"
    gen:
      kotlin:
        out: "src/main/kotlin/com/example/foo"
        package: "com.example.foo"

To use the plugin, you’ll need to replace the gen mapping with the codegen collection. Add the plugin field, setting it to kt. All fields other than out need to be moved into the options mapping.

After you’re done, it should look like this for JSON.

  "sql": [
    {
      "schema": "schema.sql",
      "queries": "query.sql",
      "engine": "postgresql",
      "codegen": [
        {
          "out": "src/main/kotlin/com/example/foo",
          "plugin": "kt",
          "options": {
            "package": "com.example.foo"
          }
        }
      ]
    }
  ]

Or this for YAML.

  sql:
  - schema: "schema.sql"
    queries: "query.sql"
    engine: "postgresql"
    codegen:
    - plugin: "kt"
      out: "src/main/kotlin/com/example/foo"
      options:
        package: "com.example.foo"

Re-generate the code

Run sqlc generate. The plugin will produce the same output, so you shouldn’t see any changes. The first time sqlc generate is run, the plugin must be downloaded and compiled, resulting in a slightly longer runtime. Subsequent generate calls will be fast.