Guides

DuckDB with a Go

This guide shows you how to use DuckDB, an in-process SQL OLAP database management system, in your Go project.

To run it example, follow these steps:

1. Install the kraft CLI tool and a container runtime engine, e.g. Docker.

2. Clone the examples repository and cd into the examples/duckdb-go/ directory:

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git clone https://github.com/kraftcloud/examples
cd examples/duckdb-go/

Make sure to log into Unikraft Cloud by setting your token and a metro close to you. We use fra0 (Frankfurt, 🇩🇪) in this guide:

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# Set Unikraft Cloud access token
export UKC_TOKEN=token
# Set metro to Frankfurt, DE
export UKC_METRO=fra0

When done, invoke the following command to deploy this application on Unikraft Cloud:

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kraft cloud deploy -p 443:8080 .

The output shows the instance URL and other details:

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[●] Deployed successfully!
 │
 ├────────── name: duckdb-go-qfd8x
 ├────────── uuid: 90960d27-458b-4dd7-a037-2a9a3a47f095
 ├───────── state: running
 ├─────────── url: https://autumn-gorilla-hg4h6sup.fra0.kraft.host
 ├───────── image: duckdb-go@sha256:6999293f8694ac00beb6a1d639fab8f96f78c2e6ecb8ccb2311539908895a699
 ├───── boot time: 32.12 ms
 ├──────── memory: 128 MiB
 ├─────── service: autumn-gorilla-hg4h6sup
 ├── private fqdn: duckdb-go-qfd8x.internal
 ├──── private ip: 172.16.6.2
 └────────── args: /server

In this case, the instance name is duckdb-go-qfd8x and the URL is https://autumn-gorilla-hg4h6sup.fra0.kraft.host. They are different for each run.

Use curl to query the Unikraft Cloud instance of DuckDB.

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curl https://autumn-gorilla-hg4h6sup.fra0.kraft.host

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id: %d, name: %s 42 John

At any point in time, you can list information about the instance:

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kraft cloud instance list

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NAME               FQDN                              STATE    CREATED AT    IMAGE         MEMORY   ARGS      BOOT TIME
duckdb-go-qfd8x    autumn-gorilla-hg4h6sup.fra0.k... running  1 minute ago  duckdb-go...  128 MiB  /server   32118us

When done, you can remove the instance:

Code
 
kraft cloud instance remove duckdb-go-qfd8x

Customize your Application

To customize the application, update the files in the repository, listed below:

• src/main.go: the Go web server frontend
• Kraftfile: the Unikraft Cloud specification, including command-line arguments
• Dockerfile: the Docker-specified application filesystem

The following options are available for customizing the application:

• If only updating the implementation in the main.go source file, no other change is required.

• If new files are added, these have to be copied in the application filesystem, using the COPY command in the Dockerfile.

• If new source code files are added, they have to be built using the corresponding go build command.

• If a new executable is built, update the cmd line in the Kraftfile and replace /server with the path to the new executable.

• More extensive changes may require expanding the Dockerfile with additional Dockerfile commands.

Learn More

Use the --help option for detailed information on using Unikraft Cloud:

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kraft cloud --help

Or visit the CLI Reference.