Deploy DuckDB with a Go Web Server
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:
-
Install the
kraft
CLI tool and a container runtime engine, e.g. Docker. -
Clone the
examples
repository andcd
into theexamples/duckdb-go/
directory:
git clone https://github.com/kraftcloud/examplescd 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:
# Set Unikraft Cloud access tokenexport UKC_TOKEN=token# Set metro to Frankfurt, DEexport UKC_METRO=fra0
When done, invoke the following command to deploy this application on Unikraft Cloud:
kraft cloud deploy -p 443:8080 .
The output shows the instance URL and other details:
[●] 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.
curl https://autumn-gorilla-hg4h6sup.fra0.kraft.host
id: %d, name: %s 42 John
At any point in time, you can list information about the instance:
kraft cloud instance list
NAME FQDN STATE CREATED AT IMAGE MEMORY ARGS BOOT TIMEduckdb-go-qfd8x autumn-gorilla-hg4h6sup.fra0.k... running 1 minute ago duckdb-go... 128 MiB /server 32118us
When done, you can remove the instance:
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 frontendKraftfile
: the Unikraft Cloud specification, including command-line argumentsDockerfile
: the Docker-specified application filesystem
package main
import ( "database/sql" "fmt" "net/http"
_ "github.com/marcboeker/go-duckdb")
func main() { db, _ := sql.Open("duckdb", "")
db.Exec(`CREATE TABLE person (id INTEGER, name VARCHAR)`) db.Exec(`INSERT INTO person VALUES (42, 'John')`)
var ( id int name string ) row := db.QueryRow(`SELECT id, name FROM person`) _ = row.Scan(&id, &name) fmt.Println("id:", id, "name:", name)
// Serve the print on port 8080 as a http server http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) { fmt.Fprintln(w, "id: %d, name: %s", id, name) }) http.ListenAndServe(":8080", nil)}
spec: v0.6
runtime: base:latest
rootfs: ./Dockerfile
cmd: ["/server"]
FROM golang:1.21.3-bookworm AS build
WORKDIR /src
COPY ./src /src
RUN set -xe; \ go build \ -buildmode=pie \ -ldflags "-linkmode external -extldflags -static-pie" \ -tags netgo \ -o /server /src/... \ ;
FROM scratch
COPY --from=build /server /serverCOPY --from=build /lib/x86_64-linux-gnu/libc.so.6 /lib/x86_64-linux-gnu/COPY --from=build /lib64/ld-linux-x86-64.so.2 /lib64/
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 theDockerfile
. -
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 theKraftfile
and replace/server
with the path to the new executable. -
More extensive changes may require expanding the
Dockerfile
with additionalDockerfile
commands.
Learn More
Use the --help
option for detailed information on using Unikraft Cloud:
kraft cloud --help
Or visit the CLI Reference.