db721

This repository is based on https://github.com/duckdb/extension-template, check it out if you want to build and ship your own DuckDB extension.

---

This extension, db721, allow you to ... <extension_goal>.

Building

Dependencies

DuckDB extensions use VCPKG for dependency management. To demonstrate that, the example extension in the template links against OpenSSL. Enabling VCPKG is very simple: follow the installation instructions and export the following variable:

export VCPKG_TOOLCHAIN_PATH=<path_to_your_vcpkg_installation>/scripts/buildsystems/vcpkg.cmake

Note: while using VCPKG for installation is recommended, the build will still work as long as CMake's find_package function is able to locate a compatible openssl version. Alternatively, feel free to remove the OpenSSL dependency completely to build the example extension without dependencies.

Build steps

Now to build the extension, run:

make

The main binaries that will be built are:

./build/release/duckdb
./build/release/test/unittest
./build/release/extension/db721/db721.duckdb_extension

• duckdb is the binary for the duckdb shell with the extension code automatically loaded.
• unittest is the test runner of duckdb. Again, the extension is already linked into the binary.
• db721.duckdb_extension is the loadable binary as it would be distributed.

Running the extension

To run the extension code, simply start the shell with ./build/release/duckdb.

Now we can use the features from the extension directly in DuckDB. The template contains a single scalar function db721() that takes a string arguments and returns a string:

D select db721('Jane') as result;
┌───────────────┐
│    result     │
│    varchar    │
├───────────────┤
│ Quack Jane 🐥 │
└───────────────┘

Running the tests

Different tests can be created for DuckDB extensions. The primary way of testing DuckDB extensions should be the SQL tests in ./test/sql. These SQL tests can be run using:

make test

Installing the deployed binaries

To install your extension binaries from S3, you will need to do two things. Firstly, DuckDB should be launched with the allow_unsigned_extensions option set to true. How to set this will depend on the client you're using. Some examples:

CLI:

duckdb -unsigned

Python:

con = duckdb.connect(':memory:', config={'allow_unsigned_extensions' : 'true'})

NodeJS:

db = new duckdb.Database(':memory:', {"allow_unsigned_extensions": "true"});

Secondly, you will need to set the repository endpoint in DuckDB to the HTTP url of your bucket + version of the extension you want to install. To do this run the following SQL query in DuckDB:

SET custom_extension_repository='bucket.s3.eu-west-1.amazonaws.com/<your_extension_name>/latest';

Note that the /latest path will allow you to install the latest extension version available for your current version of DuckDB. To specify a specific version, you can pass the version instead.

After running these steps, you can install and load your extension using the regular INSTALL/LOAD commands in DuckDB:

INSTALL db721
LOAD db721