Deploying a Deno Express application to Fly

In this tutorial you will learn how to deploy a containerized Deno Express application to Fly.

The final code of this article can be found here.

• A Fly account
• A computer with Deno, Docker, and Flyctl (the Fly CLI)

#

Creating the application

deps.ts

export
 
{
 
default
 
as
 express 
}
 
from
 
"npm:[email protected]"
;

main.ts

import
 
{
 express 
}
 
from
 
"./deps.ts"
;

const
 application 
=
 
express
(
)
;

const
 port 
=
 
8080
;

application
  
.
get
(
"/"
,
 
(
req
,
 res
)
 
=>
 
{
    res
.
send
(
{
      message
:
 
"Hello, World!"
,
    
}
)
;
  
}
)
  
.
get
(
"/random"
,
 
(
req
,
 res
)
 
=>
 
{
    res
.
send
(
{
      
number
:
 
Math
.
floor
(
Math
.
random
(
)
 
*
 
100
)
,
    
}
)
;
  
}
)
;

application
.
listen
(
port
,
 
(
)
 
=>
 
{
  
console
.
log
(
`
Application listening on port 
${
port
}
`
)
;
}
)
;

To run the application locally:

deno run -A main.ts

#

Containerizing the application

Dockerfile

FROM
 denoland/deno:alpine-1.30.0

WORKDIR
 /usr/src/app

COPY
 deps.ts .
RUN
 deno cache deps.ts

ADD
 . .
RUN
 deno cache main.ts

EXPOSE
 8080

CMD
 [
"run"
, 
"-A"
, 
"main.ts"
]

To build and run the container locally:

docker
 build 
.
 -t hello-world
docker
 run -dp 
8080
:8080 hello-world

#

Deploying the application

1. fly launch to prepare your fly.toml file, containing your project settings.
   Inside the fly.toml file, ensure the service’s internal_port (8080 by default) matches the port exposed by your container.
2. fly deploy to deploy your application.
3. fly open to open the deployed application in your browser.

#

Cleaning up

fly destroy your-unique-app-id -y removes your application from the Fly platform.

That’s all! Don’t forget to delete the application once you’re done testing.

The final code of this article can be found here.