CODEWITHSUNDEEP
cloudflarecloudflare-workers
tzador
tzador

Reputation: 2631

Detecting if we are running in dev mode or in production mode in CloudFlare Worker

I need to know in my worker script if it is running using wrangler dev locally or it is running at cloudflare after wrangelr publish.

Is there an environment variable that tells me that, or a request headers?

Code snippet would be highly appreciated.

Upvotes: 2

Views: 3092

Answers (4)

ffflabs
ffflabs

Reputation: 17481

There isn't a builtin variable, but you can populate such info yourself by defining environments in your wrangler.toml

For example, if we say the topmost [vars] are meant to be used in production, we can declare another variable set meant to be used in local environment. (the environment name is irrelevant)

type = "webpack"
webpack_config = "webpack.config.js"

# these will be used in production
vars = { WORKER_ENV = "production", SENTRY_ENABLED = true }

[env.local]
# these will be used only when --env=local
vars = { WORKER_ENV = "local", SENTRY_ENABLED = false }

From then on, if you run your worker locally using

wrangler dev --env=local

the value of binding WORKER_ENV will be populated as defined under [env.local.vars].

By the way, the syntax of wrangler.toml above is equivalent to

type = "webpack"
webpack_config = "webpack.config.js"

[vars]
  WORKER_ENV = "production"
  SENTRY_ENABLED = true

[env]

  [env.local]

    [env.local.vars]
      WORKER_ENV = "local"
      SENTRY_ENABLED = false

Which I believe it's easier to understand

Upvotes: 4

RikH
RikH

Reputation: 3414

What also could work is to use different build commands locally and for releases.

For a CompiledWasm script, I set the following in wrangler.toml:

[build]
command = "cargo install -q worker-build && worker-build --debug"

Now in local development, the following function returns false:

pub fn is_release() -> bool {
    cfg!(not(debug_assertions))
}

Next, in the CI release configuration, I've added a Bash script to overwrite the --debug flag:

 - run: |
     command = "cargo install -q worker-build && worker-build"
     sed -i 's/worker-build --debug/worker-build --release/' wrangler.toml
     if grep -q "worker-build --release" wrangler.toml; then
       echo "Replacement succeeded"
     else
       echo "Replacement failed"
       exit 1
     fi

This avoids having to pass the RouteContext around in order to check whether the program is in release or development mode.

Upvotes: 0

Giangimgs
Giangimgs

Reputation: 1200

This is the way that I am using:

Create a file .dev.var in the root of project and define a variable to detect the environment. In below ex I am using IS_LOCAL_MODE

IS_LOCAL_MODE=1

Now put this variable to Cloudflare to use it in the production environment

wrangler secret put IS_LOCAL_MODE

Then fill the value is 0

That's it. Now in your code, to check the mode we will do something like this

if(env.IS_LOCAL_MODE == 1){
    console.log("Hello admin, you are in dev mode")
}else{
    console.log("Silence is gold!")
}

Upvotes: 0

Dom Eden
Dom Eden

Reputation: 131

I believe there is an official update for this now (as of November 2022):

When developing locally, you can create a .dev.vars file in the project root which allows you to define variables that will be used when running wrangler dev or wrangler pages dev, as opposed to using another environment and [vars] in wrangler.toml.

Cloudflare Workers documentation

Upvotes: 2

Related Questions