Serverless Build Client
A Serverless Framework plugin for building the frontend with environment variables defined in serverless.yml
Introduction
Plugins such as serverless-finch
make it easy to host static websites in S3. These websites usually need to be built before being uploaded. Without this plugin, environment variables defined in serverless.yml
will not be included in the build.
Table of Contents
Installation
First, install the package to your dev dependencies
$ yarn add --dev serverless-build-client
Then add the plugin to your serverless.yml
file
...
plugins:
- serverless-build-client
...
Usage
In your command prompt, run the following command to build the client
serverless client build
This will add all of the environment variables in your serverless.yml
file to process.env
, and then it will execute yarn build
to build the frontend
Options
--packager
, -p
The packager that should be used to build the client. Valid options are yarn
and npm
. Default value is yarn
Example
$ serverless client build --packager yarn
--command
, -c
The command that will build the client. Default value is build
for yarn and run build
for npm
Examples
$ serverless client build --packager yarn --command build
$ serverless client build --packager npm --command "run build"
--cwd
, -d
The directory that will be used to run the packager. Default value is the current folder. This option is intended for use when the client package.json is in a subfolder or alternate folder.
Example
$ serverless client build --packager npm --command "run build" --cwd client
--verbose
, -v
Flag that determines if we should print the environment variables to the console. Default value is false
Example
$ serverless client build --verbose
Configuration
Options
The above options may also be configured using custom configuration options in your servless.yml
file
...
custom:
buildClient:
packager: npm
command: run build
cwd: client
verbose: true
Environment variables
Environment variables may be set for the entire provider:
provider:
environment:
REACT_APP_BACKEND_ENDPOINT: ${cf:<backend service name>.ServiceEndpoint}
Or they may be set specificly for this plugin:
custom:
buildClient:
environment:
REACT_APP_BACKEND_ENDPOINT: ${cf:<backend service name>.ServiceEndpoint}
The plugin will apply both provider environment variables and specific plugin environment variables. In the case of a conflict, the specific plugin environment variable will override the provider environment variable.
Example
Let's say you have two separate Serverless Framework projects: one for the frontend, and one for the backend. When you deploy the backend service, a ServiceEndpoint
is automatically outputted in the CloudFormation stack.
In order to avoid hardcoding this value, the frontend should reference an environment variable containing the endpoint. In your frontend's serverless.yml
file, you would have something similar to
...
provider:
...
environment:
REACT_APP_BACKEND_ENDPOINT: ${cf:<backend service name>.ServiceEndpoint}
...
or
...
custom:
buildClient:
environment:
REACT_APP_BACKEND_ENDPOINT: ${cf:<backend service name>.ServiceEndpoint}
...
To deploy your front end, you need to run a series of commands (in this example, I am using serverless-finch
)
$ serverless deploy
$ serverless client build
$ serverless client deploy --no-confirm
These commands will first deploy your application to AWS. Then it will build the front end with the environment variable defined above. Then it will upload the built website to S3.