Environments

​Background

Environments is a feature that allows you to deploy the same project to multiple places under multiple names. These environments are utilized with the --env or -e flag on wrangler build, wrangler preview, and wrangler publish.

​Usage

The most common use case for environments is deploying to a staging subdomain before your production environment. wrangler publish will look at your top level configuration, and you can specify other environments beneath it. For details on what keys are inherited see wrangler.toml configuration.

​Naming

You cannot specify multiple environments with the same name. If this were allowed, publishing each environment would overwrite your previously deployed worker, and the behavior would not be clear.

For this reason wrangler appends the environment name to the top-level name to publish a Worker script. For example, a Worker project named my-worker with an environment [env.dev] would become my-worker-dev.

​Examples

​Top level configuration

​Routes

This wrangler.toml has no environments defined and will publish my-worker to example.com/*

wrangler.tomltype = "webpack"name = "my-worker"account_id = "12345678901234567890"zone_id = "09876543210987654321"route = "example.com/*"

~/my-worker $ wrangler publish✨  Built successfully, built project size is 523 bytes.✨  Successfully published your script to example.com/*

​workers.dev

This wrangler.toml has no environments defined and will publish my-worker to my-worker.<your-subdomain>.workers.dev

wrangler.tomltype = "webpack"name = "my-worker"account_id = "12345678901234567890"
# this field specifies that the worker# should be deployed to workers.devworkers_dev = true

~/my-worker $ wrangler publish✨  Built successfully, built project size is 523 bytes.✨  Successfully published your script to https://my-worker.<your-subdomain>.workers.dev

​Introducing environments

This wrangler.toml adds two environments to the base case. Note that you must provide a route/routes key for each environment if you are deploying to a custom domain.

wrangler.tomltype = "webpack"name = "my-worker-dev"account_id = "12345678901234567890"zone_id = "09876543210987654321"route = "dev.example.com/*"vars = { ENVIRONMENT = "dev" }
[env.staging]name = "my-worker-staging"vars = { ENVIRONMENT = "staging" }route = "staging.example.com/*"
[env.production]name = "my-worker"vars = { ENVIRONMENT = "production" }routes = [  "example.com/foo/*",  "example.com/bar/*"]

In order to use environments with this configuration, you can pass the name of the environment via the --env flag.

With this configuration, Wrangler will behave in the following manner:

~/my-worker $ wrangler publish✨  Built successfully, built project size is 523 bytes.✨  Successfully published your script to dev.example.com/*

~/my-worker $ wrangler publish --env staging✨  Built successfully, built project size is 523 bytes.✨  Successfully published your script to staging.example.com/*

~/my-worker $ wrangler publish --env production✨  Built successfully, built project size is 523 bytes.✨  Successfully published your script to example.com/*

Once a text variable is uploaded via wrangler or in the UI, the string is exposed on the global namespace as type String.

With this configuration, the ENVIRONMENT variable can be used to call specific code depending on the given environment:

if (ENVIRONMENT === "staging") {  // staging-specific code} else if (ENVIRONMENT === "production") {  // production-specific code}

​Staging Environment with workers.dev

In order to deploy your code to workers.dev, you must include workers_dev = true in the desired environment. Your wrangler.toml may look like this:

wrangler.tomlname = "my-worker"type = "webpack"account_id = "12345678901234567890"zone_id = "09876543210987654321"route = "example.com/*"
[env.staging]workers_dev = true

With this configuration, Wrangler will behave in the following manner:

~/my-worker $ wrangler publish✨  Built successfully, built project size is 523 bytes.✨  Successfully published your script to example.com/*

~/my-worker $ wrangler publish --env staging✨  Built successfully, built project size is 523 bytes.✨  Successfully published your script to https://my-worker-staging.<your-subdomain>.workers.dev

​workers.dev as a first class target

If you only want to deploy to workers.dev you can configure Wrangler like so:

name = "my-worker-dev"type = "webpack"account_id = "12345678901234567890"workers_dev = true
[env.production]name = "my-worker"
[env.staging]name = "my-worker-staging"

With this configuration, Wrangler will behave in the following manner:

~/my-worker $ wrangler publish✨  Built successfully, built project size is 523 bytes.✨  Successfully published your script to https://my-worker-dev.<your-subdomain>.workers.dev

~/my-worker $ wrangler publish --env staging✨  Built successfully, built project size is 523 bytes.✨  Successfully published your script to https://my-worker-staging.<your-subdomain>.workers.dev

~/my-worker $ wrangler publish --env production✨  Built successfully, built project size is 523 bytes.✨  Successfully published your script to https://my-worker.<your-subdomain>.workers.dev

​Custom webpack configurations

You can specify different webpack configurations for different environments.

wrangler.tomlname = "my-worker-dev"type = "webpack"account_id = "12345678901234567890"workers_dev = truewebpack_config = "webpack.dev.js"
[env.production]name = "my-worker"webpack_config = "webpack.config.js"
[env.staging]name = "my-worker-staging"

Your default wrangler build, wrangler preview, and wrangler publish commands will all build with webpack.dev.js, as will wrangler build -e staging, wrangler preview -e staging, and wrangler publish -e staging.

The build commands wrangler build -e production, wrangler preview -e production, and wrangler publish -e production would all use your webpack.config.js file.

​Environment variables

You can specify different KV namespaces, secrets, and text variables for different environments.

wrangler.tomlname = "my-worker"type = "webpack"account_id = "12345678901234567890"workers_dev = truekv_namespaces = [  { binding = "KV", id = "06779da6940b431db6e566b4846d64db" }]
[env.production]kv_namespaces = [  { binding = "KV", id = "bd46d6484b665e6bd134b0496ad97760" }]vars = {FOO = "some text"}

​Invalid configurations

​Multiple types

You cannot specify a type for each environment, type must be specified at the top level of your wrangler.toml.

wrangler.tomlname = "my-worker"type = "webpack"account_id = "12345678901234567890"zone_id = "09876543210987654321"route = "example.com/*"workers_dev = true
[env.staging]type = "rust"

Wrangler will not error with this configuration, it will build with the webpack type.

​Same name for multiple environments

You cannot specify multiple environments with the same name. If this were allowed, publishing each environment would overwrite your previously deployed worker, and the behavior would not be clear.

wrangler.tomlname = "my-worker"type = "webpack"account_id = "12345678901234567890"zone_id = "09876543210987654321"route = "example.com/*"
[env.staging]name = "my-worker"workers_dev = true

~/my-worker $ wrangler publishError: ⚠️  Each name in your `wrangler.toml` must be unique, this name is duplicated: my-worker

~/my-worker $ wrangler publish --env stagingError: ⚠️  Each name in your `wrangler.toml` must be unique, this name is duplicated: my-worker

​Defining workers_dev and route

name = "my-worker"type = "webpack"account_id = "12345678901234567890"zone_id = "09876543210987654321"route = "example.com/*"workers_dev = true
[env.staging]workers_dev = trueroute = "staging.example.com/*"

Wrangler will fail to publish to an environment where route is defined alongside workers_dev = true.

~/my-worker $ wrangler publish publishError: ⚠️  Your environment should only include `workers_dev` or `route`. If you are trying to publish to workers.dev, remove `route` from your wrangler.toml, if you are trying to publish to your own domain, remove `workers_dev`.

~/my-worker $ wrangler publish publish --env stagingError: ⚠️  Your environment should only include `workers_dev` or `route`. If you are trying to publish to workers.dev, remove `route` from your wrangler.toml, if you are trying to publish to your own domain, remove `workers_dev`.