@salomvary/serverless-webpack
Advanced tools
Serverless plugin to bundle your javascript with Webpack
A Serverless v1.x plugin to build your lambda functions with Webpack.
This plugin is for you if you want to use the latest Javascript version with Babel; use custom resource loaders, optimize your packaged functions individually and much more!
serverless package, serverless deploy and serverless deploy functionserverless invoke local and serverless invoke local --watchserverless run and serverless run --watchserverless-offline to simulate local API Gateway endpointscustom.webpack object to configure everything relevant for the plugin. The old configuration still works but will be removed in the next major release. For details see below.For the complete release notes see the end of this document.
$ npm install serverless-webpack --save-dev
Add the plugin to your serverless.yml file:
plugins:
- serverless-webpack
The configuration of the plugin is done by defining a custom: webpack object in your serverless.yml with your specific configuration. All settings are optional and will be set to reasonable defaults if missing.
See the sections below for detailed descriptions of the settings. The defaults are:
custom:
webpack:
webpackConfig: 'webpack.config.js' # Name of webpack configuration file
includeModules: false # Node modules configuration for packaging
packager: 'npm' # Packager that will be used to package your external modules
excludeFiles: src/**/*.test.js # Provide a glob for files to ignore
By default the plugin will look for a webpack.config.js in the service directory. Alternatively, you can specify a different file or configuration in serverless.yml.
custom:
webpack:
webpackConfig: ./folder/my-webpack.config.js
A base Webpack configuration might look like this:
// webpack.config.js
module.exports = {
entry: './handler.js',
target: 'node',
module: {
loaders: [ ... ]
}
};
Alternatively the Webpack configuration can export an asynchronous object (e.g. a promise or async function) which will be awaited by the plugin and resolves to the final configuration object. This is useful if the confguration depends on asynchronous functions, for example, defining the AccountId of the current aws user inside AWS lambda@edge which does not support defining normal process environment variables.
A basic Webpack promise configuration might look like this:
// Version if the local Node.js version supports async/await
// webpack.config.js
const webpack = require('webpack')
const slsw = require('serverless-webpack');
module.exports = (async () => {
const accountId = await slsw.lib.serverless.providers.aws.getAccountId();
return {
entry: './handler.js',
target: 'node',
plugins: [
new webpack.DefinePlugin({
AWS_ACCOUNT_ID: `${accountId}`,
}),
],
module: {
loaders: [ ... ]
}
};
})();
// Version with promises
// webpack.config.js
const webpack = require('webpack')
const slsw = require('serverless-webpack');
const BbPromise = require('bluebird');
module.exports = BbPromise.try(() => {
return slsw.lib.serverless.providers.aws.getAccountId()
.then(accountId => ({
entry: './handler.js',
target: 'node',
plugins: [
new webpack.DefinePlugin({
AWS_ACCOUNT_ID: `${accountId}`,
}),
],
module: {
loaders: [ ... ]
}
}));
});
serverless-webpack exposes a lib object, that can be used in your webpack.config.js to make the configuration easier and to build fully dynamic configurations. This is the preferred way to configure webpack - the plugin will take care of as much of the configuration (and subsequent changes in your services) as it can.
You can let the plugin determine the correct handler entry points at build time. Then you do not have to care anymore when you add or remove functions from your service:
// webpack.config.js
const slsw = require('serverless-webpack');
module.exports = {
...
entry: slsw.lib.entries,
...
};
Custom entries that are not part of the SLS build process can be added too:
// webpack.config.js
const _ = require('lodash');
const slsw = require('serverless-webpack');
module.exports = {
...
entry: _.assign({
myCustomEntry1: './custom/path/something.js'
}, slsw.lib.entries),
...
};
The lib export also provides the serverless and options properties, through
which you can access the Serverless instance and the options given on the command-line.
The current stage e.g is accessible through slsw.lib.options.stage
This enables you to have a fully customized dynamic configuration, that can evaluate anything available in the Serverless framework. There are really no limits.
Samples are: The current stage and the complete service definition. You thereby have access to anything that a Serverless plugin would have access to.
Both properties should be handled with care and should never be written to, as that will modify the running framework and leads to unpredictable behavior!
If you have cool use cases with the full customization, we might add your solution to the plugin examples as showcase.
lib.webpack contains state variables that can be used to configure the build
dynamically on a specific plugin state.
lib.webpack.isLocal is a boolean property that is set to true, if any known
mechanism is used in the current Serverless invocation that runs code locally.
This allows to set properties in the webpack configuration differently depending if the lambda code is run on the local machine or deployed.
A sample is to set the compile mode with Webpack 4:
mode: slsw.lib.webpack.isLocal ? "development" : "production"
Note that, if the output configuration is not set, it will automatically be
generated to write bundles in the .webpack directory. If you set your own output
configuration make sure to add a libraryTarget
for best compatibility with external dependencies:
// webpack.config.js
const path = require('path');
module.exports = {
// ...
output: {
libraryTarget: 'commonjs',
path: path.resolve(__dirname, '.webpack'),
filename: '[name].js',
},
// ...
};
By default, the plugin will print a quite verbose bundle information to your console. However, if
you are not satisfied with the current output info, you can overwrite it in your webpack.config.js
// webpack.config.js
module.exports = {
// ...
stats: 'minimal'
// ...
}
All the stats config can be found in webpack's documentation
By default, the plugin will try to bundle all dependencies. However, you don't
want to include all modules in some cases such as selectively import, excluding
builtin package (ie: aws-sdk) and handling webpack-incompatible modules.
In this case you might add external modules in
Webpack's externals configuration.
Those modules can be included in the Serverless bundle with the custom: webpack: includeModules
option in serverless.yml:
// webpack.config.js
var nodeExternals = require('webpack-node-externals')
module.exports = {
// we use webpack-node-externals to excludes all node deps.
// You can manually set the externals too.
externals: [nodeExternals()],
}
# serverless.yml
custom:
webpack:
includeModules: true # enable auto-packing of external modules
All modules stated in externals will be excluded from bundled files. If an excluded module
is stated as dependencies in package.json and it is used by the webpack chunk, it will be
packed into the Serverless artifact under the node_modules directory.
By default, the plugin will use the package.json file in working directory, If you want to
use a different package file, set packagePath to your custom package.json:
# serverless.yml
custom:
webpack:
includeModules:
packagePath: '../package.json' # relative path to custom package.json file.
Note that only relative path is supported at the moment.
If a runtime dependency is detected that is found in the devDependencies section and
so would not be packaged, the plugin will error until you explicitly exclude it (see forceExclude below)
or move it to the dependencies section.
An exception for the runtime dependency error is the AWS-SDK. All projects using the AWS-SDK normally
have it listed in devDependencies because AWS provides it already in their Lambda environment. In this case
the aws-sdk is automatically excluded and only an informational message is printed (in --verbose mode).
The main reason for the warning is, that silently ignoring anything contradicts the declarative nature
of Serverless' service definition. So the correct way to define the handling for the aws-sdk is, as
you would do for all other excluded modules (see forceExclude below).
# serverless.yml
custom:
webpack:
includeModules:
forceExclude:
- aws-sdk
You can select the packager that will be used to package your external modules. The packager can be set with the packager configuration. Currently it can be 'npm' or 'yarn' and defaults to using npm when not set.
# serverless.yml
custom:
webpack:
packager: 'yarn' # Defaults to npm
packagerOptions: {} # Optional, depending on the selected packager
You should select the packager, that you use to develop your projects, because only then locked versions will be handled correctly, i.e. the plugin uses the generated (and usually committed) package lock file that is created by your favorite packager.
Each packager might support specific options that can be set in the packagerOptions
configuration setting. For details see below.
By default, the plugin uses NPM to package the external modules. However, if you use npm,
you should use any version <5.5 >=5.7.1 as the versions in-between have some nasty bugs.
Right now there are no packagerOptions that can be set with NPM.
Using yarn will switch the whole packaging pipeline to use yarn, so does it use a yarn.lock file.
The yarn packager supports the following packagerOptions:
| Option | Type | Default | Description |
|---|---|---|---|
| ignoreScripts | bool | true | Do not execute package.json hook scripts on install |
There are some settings that are common to all packagers and affect the packaging itself.
You can specify custom scripts that are executed after the installation of the function/service packages
has been finished. These are standard packager scripts as they can be used in any package.json.
Warning: The use cases for them are very rare and specific and you should investigate first,
if your use case can be covered with webpack plugins first. They should never access files
outside of their current working directory which is the compiled function folder, if any.
A valid use case would be to start anything available as binary from node_modules.
custom:
webpack:
packagerOptions:
scripts:
- npm rebuild grpc --target=6.1.0 --target_arch=x64 --target_platform=linux --target_libc=glibc
Sometimes it might happen that you use dynamic requires in your code, i.e. you
require modules that are only known at runtime. Webpack is not able to detect
such externals and the compiled package will miss the needed dependencies.
In such cases you can force the plugin to include certain modules by setting
them in the forceInclude array property. However the module must appear in
your service's production dependencies in package.json.
# serverless.yml
custom:
webpack:
includeModules:
forceInclude:
- module1
- module2
You can forcefully exclude detected external modules, e.g. if you have a module in your dependencies that is already installed at your provider's environment.
Just add them to the forceExclude array property and they will not be packaged.
# serverless.yml
custom:
webpack:
includeModules:
forceExclude:
- module1
- module2
If you specify a module in both arrays, forceInclude and forceExclude, the
exclude wins and the module will not be packaged.
You can use file: version references in your package.json to use a node module
from a local folder (e.g. "mymodule": "file:../../myOtherProject/mymodule").
With that you can do test deployments from the local machine with different
module versions or modules before they are published officially.
If you have a project structure that uses something like index.js and a
co-located index.test.js then you have likely seen an error like:
WARNING: More than one matching handlers found for index. Using index.js
This config option allows you to exlcude files that match a glob from function
resolution. Just add: excludeFiles: **/*.test.js (with whatever glob you want
to exclude).
# serverless.yml
custom:
webpack:
excludeFiles: **/*.test.js
This is also useful for projects that use TypeScript.
You can keep the output directory (defaults to .webpack) from being removed
after build.
Just add keepOutputDirectory: true
# serverless.yml
custom:
webpack:
keepOutputDirectory: true
This can be useful, in case you want to upload the source maps to your Error reporting system, or just have it available for some post processing.
You can find an example setups in the examples folder.
If you do not enable individual packaging in your service (serverless.yml), the plugin creates one ZIP file for all functions (the service package) that includes all node modules used in the service. This is the fastest packaging, but not the optimal one, as node modules are always packaged, that are not needed by some functions.
A better way to do the packaging, is to enable individual packaging in your service:
# serverless.yml
...
package:
individually: true
...
This will switch the plugin to per function packaging which makes use of the multi-compiler feature of Webpack. That means, that Webpack compiles and optimizes each function individually, removing unnecessary imports and reducing code sizes significantly. Tree-Shaking only makes sense with this approach.
Now the needed external node modules are also detected by Webpack per function and the plugin only packages the needed ones into the function artifacts. As a result, the deployed artifacts are smaller, depending on the functions and cold-start times (to install the functions into the cloud at runtime) are reduced too.
The individual packaging will automatically apply the automatic entry resolution (see above) and you will not be able to configure the entry config in webpack. An error will be thrown if you are trying to override the entry in webpack.config.js with other unsupported values.
The individual packaging needs more time at the packaging phase, but you'll get that paid back twice at runtime.
The normal Serverless deploy procedure will automatically bundle with Webpack:
serverless create -t aws-nodejsserverless deployThe plugin fully integrates with serverless invoke local. To run your bundled functions
locally you can:
$ serverless invoke local --function <function-name>
All options that are supported by invoke local can be used as usual:
--function or -f (required) is the name of the function to run--path or -p (optional) is a JSON file path used as the function input event--data or -d (optional) inline JSON data used as the function input event:exclamation: The old
webpack invokecommand has been disabled.
On CI systems it is likely that you'll run multiple integration tests with invoke local
sequentially. To improve this, you can do one compile and run multiple invokes on the
compiled output - it is not necessary to compile again before each and every invoke.
$ serverless webpack
$ serverless invoke local --function <function-name-1> --no-build
$ serverless invoke local --function <function-name-2> --no-build
...
Or to run a function every time the source files change use the --watch option
together with serverless invoke local:
$ serverless invoke local --function <function-name> --path event.json --watch
Everytime the sources are changed, the function will be executed again with the changed sources. The command will watch until the process is terminated.
If you have your sources located on a file system that does not offer events,
you can enable polling with the --webpack-use-polling=<time in ms> option.
If you omit the value, it defaults to 3000 ms.
All options that are supported by invoke local can be used as usual:
--function or -f (required) is the name of the function to run--path or -p (optional) is a JSON file path used as the function input event--data or -d (optional) inline JSON data used as the function input event:exclamation: The old
webpack watchcommand has been disabled.
The serverless run command is supported with the plugin. To test a local
service with the Serverless Emulator, you can use the serverless run
command as documented by Serverless. The command will compile the code before
it uploads it into the event gateway.
You can enable source watch mode with serverless run --watch. The plugin will
then watch for any source changes, recompile and redeploy the code to the event
gateway. So you can just keep the event gateway running and test new code immediately.
The plugin integrates very well with serverless-offline to simulate AWS Lambda and AWS API Gateway locally.
Add the plugins to your serverless.yml file and make sure that serverless-webpack
precedes serverless-offline as the order is important:
plugins:
...
- serverless-webpack
...
- serverless-offline
...
Run serverless offline or serverless offline start to start the Lambda/API simulation.
In comparison to serverless offline, the start command will fire an init and a end lifecycle hook which is needed for serverless-offline and e.g. serverless-dynamodb-local to switch off resources (see below).
You can find an example setup in the examples folder.
By default the plugin starts in watch mode when triggered through serverless offline, i.e.
it automatically recompiles your code if it detects a change in the used sources.
After a change it might take some seconds until the emulated endpoints are updated.
If you have your sources located on a file system that does not offer events,
e.g. a mounted volume in a Docker container, you can enable polling with the
--webpack-use-polling=<time in ms> option. If you omit the value, it defaults
to 3000 ms.
If you do not use the default path and override it in your Webpack configuration,
you have use the --location option.
Configure your service the same as mentioned above, but additionally add the serverless-dynamodb-local
plugin as follows:
plugins:
- serverless-webpack
- serverless-dynamodb-local
- serverless-offline
Run serverless offline start.
You can reduce the clutter generated by serverless-offline with --dontPrintOutput and
disable timeouts with --noTimeout.
If you use serverless offline to run your integration tests, you might want to
disable the automatic watch mode with the --webpack-no-watch switch.
To just bundle and see the output result use:
$ serverless webpack --out dist
Options are:
--out or -o (optional) The output directory. Defaults to .webpack.:exclamation: The serve command has been removed. See above how to achieve the
same functionality with the serverless-offline plugin.
To debug your functions using serverless invoke local or serverless-offline
check this .vscode/launch.json example.
In the examples folder there is a Serverless project using this
plugin with Babel. To try it, from inside the example folder:
npm install to install dependenciesserverless invoke local -f hello to run the example functionPlugin commands are supported by the following providers. ⁇ indicates that command has not been tested with that provider.
| AWS Lambda | Apache OpenWhisk | Azure Functions | Google Cloud Functions | |
|---|---|---|---|---|
| webpack | ✔︎ | ✔︎ | ⁇ | ⁇ |
| invoke local | ✔︎ | ✔︎ | ⁇ | ⁇ |
| invoke local --watch | ✔︎ | ✔︎ | ⁇ | ⁇ |
The following serverless plugins are explicitly supported with serverless-webpack
| Plugin | NPM |
|---|---|
| serverless-offline |  |
| serverless-step-functions-offline |  |
The plugin exposes a complete lifecycle model that can be hooked by other plugins to extend the functionality of the plugin or add additional actions.
All events (H) can be hooked by a plugin.
-> webpack:validate
-> webpack:validate:validate (H)
-> webpack:compile
-> webpack:compile:compile (H)
-> webpack:compile:watch:compile (H)
-> webpack:package
-> webpack:package:packExternalModules (H)
-> webpack:package:packageModules (H)
The following list shows all lifecycles that are invoked/started by the plugin when running a command or invoked by a hook.
-> before:package:createDeploymentArtifacts
-> webpack:validate
-> webpack:compile
-> webpack:package
-> before:deploy:function:packageFunction
-> webpack:validate
-> webpack:compile
-> webpack:package
-> before:invoke:local:invoke
-> webpack:validate
-> webpack:compile
-> webpack
-> webpack:validate
-> webpack:compile
-> webpack:package
-> before:offline:start
-> webpack:validate
-> webpack:compile
-> before:offline:start:init
-> webpack:validate
-> webpack:compile
Special thanks go to the initial author of serverless-webpack, Nicola Peduzzi (https://github.com/thenikso), who allowed me to take it over and continue working on the project. That helped to revive it and lead it to new horizons.
5.3.1
5.3.0
5.2.0
5.1.5
5.1.4
5.1.3
5.1.2
5.1.1
5.1.0
5.0.0
4.4.0
4.3.0
4.2.0
4.1.0
4.0.0
3.1.2
3.1.1
3.1.0
--webpack-use-polling) #2153.0.0
serverless invoke local #151serverless invoke local --watchwebpack serve command in favor of serverless-offline #1522.2.2
2.2.1
2.2.0
2.1.0
2.0.0
FAQs
Serverless plugin to bundle your javascript with Webpack
We found that @salomvary/serverless-webpack demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 1 open source maintainer collaborating on the project.
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