Lambda functions often require a set of standard parameters during creation, such as security policies, non-standard timeouts or memory limits. Keeping those parameters outside the project code is error-prone, as people can make stupid mistakes during deployment. This is particularly important for effective teamwork. Also, when a team is running multiple versions of the same function for development, testing and production, it’s important that everyone remembers how individual versions are called.
A useful trick to automate such steps and avoid common problems is to store standard deployment arguments in NPM package scripts. That way, all the developers on a team will instantly have the same configuration. This is also very useful if you plan to publish your Lambda microservice as an opensource project, so that all anyone who installs it locally knows how to set it up easily. Running Claudia from NPM scripts also allows you to keep it local to a project, instead of having to install it as a global utility.
Setting up deployment scripts
First, install Claudia as a development dependency in your project. The
-D flag will save the reference to Claudia in
package.json, so the all the other collaborators get the same version when they install the package.
Next, in your project
package.json, find the
scripts section (or create it if it does not exist), and just add a few key-value pairs to it. The key is the name of the script (for example
deploy). The value is the command you want to run, with a slight twist. You can use any locally installed NPM command as if it were in the system path. For example, the following script will create a new Lambda and mark it as the
Anyone can now execute the correct Claudia command just by using:
You can add more scripts easily. For example, add a step that promotes the latest deployed copy to the
Now the rest of the team does not need to remember exactly which version is used for what, they can just run the
release script to deploy to production.
Automating scripts in this way also allows you to set up Claudia as part of your deployment pipeline and automatically use the right configuration easily.
Creating a menu system
ntl module is a nice way to create a console menu system, so people don’t even need to look up the available scripts in
package.json. Install it as a development dependency:
Then, just add a script called
start that calls
ntl to your project
Now, the only thing people need to remember is to run:
NPM will present a nice menu for the available deployment options.
For an example of NPM scripts in action, check out the Simple Bot Example Project. That project runs with ntl, so after installing, just use
npm start to see the available deployment options.
NPM reserves some package names, such as
test and so on, and it’s best to avoid using those names, otherwise you might end up calling the script unexpectedly. (In particular, avoid using the name
publish unless you really know what you’re doing). For a full reference on NPM scripts, check out the main NPM Web site.