Sharing code

Architect makes it easy to share code across Lambda functions. Out of the box, with zero configuration, code is shared across Lambdas as follows:

  • src/shared/ - files in this dir are shared across all Lambdas
  • src/views/ - files in this dir are shared to all @http get Lambdas (if any)

Additional configuration (such as folder configuration) can be managed with the @shared and @views pragmas.

Example usage

Given a simple app.arc:

@app
myapp

@http
get /
post /like

Where utility code lives in ./src/shared/ and common view code in ./src/views/:

.
├── src
│   ├── http
│   │   ├── get-index
│   │   │   └── index(.js|.py|.rb)
│   │   └── post-like
│   │       └── index(.js|.py|.rb)
│   ├── shared
│   │   └── authenticate(.js|.py|.rb)
│   └── views
│       └── document(.js|.py|.rb)
└── app.arc

get-index can use shared code by requiring it from @architect/shared/<file> and views code from @architect/views/<file>:

js
// get-index/index.js
const auth = require('@architect/shared/authenticate')
const document = require('@architect/views/document')
rb
# get-index/lambda.rb
require_relative './vendor/shared/authenticate'
require_relative './vendor/views/document'
py
# get-index/lambda.py
import vendor.shared.authenticate
import vendor.views.document

The post-like route has access to shared code as well, but not views because it is a post request handler, not a get handler.

js
// post-like/index.js
const auth = require('@architect/shared/authenticate')
rb
# post-like/lambda.rb
require_relative './vendor/shared/authenticate'
py
# post-like/lambda.py
import vendor.shared.authenticate

Custom shared paths

The default shared and views directories can be overridden:

@app
myapp

@shared
src path/to/shared

@views
src path/to/views

They are still required in the same way:

js
// get-index/index.js
const auth = require('@architect/shared/authenticate')
const document = require('@architect/views/document')
rb
# get-index/lambda.rb
require_relative './vendor/shared/authenticate'
require_relative './vendor/views/document'
py
# get-index/lambda.py
import vendor.shared.authenticate
import vendor.views.document

Runtime details

No matter where @shared source is configured it gets copied to every Lambda. The destination is slightly different depending on runtime:

Runtime @shared destination
Node src/http/get-index/node_modules/@architect/shared
Ruby src/http/get-index/vendor/shared
Python src/http/get-index/vendor/shared

Likewise, @views runtime destinations:

Runtime @views destination
Node src/http/get-index/node_modules/@architect/views
Ruby src/http/get-index/vendor/views
Python src/http/get-index/vendor/views

Tip: the entire contents of src/shared are copied so we strongly suggest keeping the directory structure as flat as possible, and the payloads as small as possible to ensure the best performance.

Shared code dependencies

@shared and @views resources can have their own dependencies defined by package.json, requirements.txt or Gemfile. These dependencies will also be copied to corresponding Lambdas.

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