Bots in Production

Editing bots in the web editor is good for getting started quickly, but as Bots become more important you will want to manage them as part of your regular software development lifecycle. This means:

• Storing bot code in source control (typically git)
• Writing unit tests for your bots
• Deploying your bots as part of your CI/CD pipeline.

This Guide will show you

• How to set up a repository to host the source code for your Bots.
• Write a new Bot in TypeScript.
• Create a new Bot resource and link it to your TypeScript file.
• Use the Medplum Command Line Interface (CLI) to create and deploy your Bot to production.

Setting up your Repository

The first thing we'll do is set up a Git repository to host your Bot code. While you can set up bots in any git repository, we provide a template Git repository to help you get started.

Note that the Medplum Bot SDK requires Node.js version 18+.

Clone the repo and install the dependencies

git clone git@github.com:medplum/medplum-demo-bots.git my-bots
cd my-bots
npm install

Setting up your Permissions

Because Bots contain important or sensitive code, it's important to prevent unauthorized users from modifying your Bots. Medplum uses the client credentials workflow authenticate the Medplum CLI.

First, you should create a Client Application on the Medplum Server by following these directions.

The Medplum CLI looks for two environment variables when authenticating: MEDPLUM_CLIENT_ID and MEDPLUM_CLIENT_SECRET.

You can set these on the command line using the export command in bash.

export MEDPLUM_CLIENT_ID=<YOUR_CLIENT_ID>
export MEDPLUM_CLIENT_SECRET=<YOUR_CLIENT_SECRET>

Alternatively, you can create a .env file to avoid having to re-export the environment variables in every new terminal. The example repository has a .env.example file you can copy to get started.

cp .env.example .env

# .env
MEDPLUM_CLIENT_ID=<YOUR_CLIENT_ID>
MEDPLUM_CLIENT_SECRET=<YOUR_CLIENT_SECRET>

Warning

Your .env file should never be checked into source control.

MEDPLUM_CLIENT_ID and MEDPLUM_CLIENT_SECRET should be considered sensitive security credentials and should never be shared in a publicly accessible store. The medplum-demo-bots repository adds .env to .gitignore by default.

If you are self-hosting Medplum, set MEDPLUM_BASE_URL to the base URL of your Medplum server as an environment variable or in your .env file.

export MEDPLUM_BASE_URL=https://api.example.com/

# .env
MEDPLUM_BASE_URL=https://api.example.com/

Create a source file

After we've installed dependencies, we can write your Bot in any typescript file under the src/ directory.

As mentioned in Bot Basics, a bot is any TypeScript file that contains a handler function with the following signature:

import { MedplumClient, BotEvent } from '@medplum/core';
export async function handler(medplum: MedplumClient, event: BotEvent): Promise<any> {
  // Your code here
}

See the Bot Basics tutorial for more details about the arguments to handler.

The starter repository contains an example Bot in the examples directory called hello-patient.ts. You can copy this example file to get started on your own bots:

cd src
cp examples/hello-patient.ts my-first-bot.ts

You'll see that this creates a simple bot that logs the patient's name to the console. For more details on how this code works, check out the Bot Basics tutorial.

// src/my-first-bot.ts
import { BotEvent, MedplumClient } from '@medplum/core';
import { Patient } from '@medplum/fhirtypes';

export async function handler(medplum: MedplumClient, event: BotEvent): Promise<any> {
  const patient = event.input as Patient;
  const firstName = patient.name?.[0]?.given?.[0];
  const lastName = patient.name?.[0]?.family;
  console.log(`Hello ${firstName} ${lastName}!`);
  return true;
}

Compiling your Bot

Congratulations! You’ve just written your first bot. Our next step will be to compile this code and link it to a Bot resource.

First, compile your code:

npm run build

This runs the tsc compiler to translate your TypeScript code to Javascript.

Next, take a look at your dist/ directory and notice how there is now a file called my-first-bot.js with the compiled version of your code.

cd ..
ls dist

# my-first-bot.d.ts
# my-first-bot.js
# my-first-bot.js.map
# examples/
# ...

Creating your Bot

Next step is to create the bot.

Navigate to the Project Admin panel and copy the ID of your project. That will be your project-id.

Taking the source-file we just created at src/my-first-bot.ts, we will use the bot create command. In our example

npx medplum bot create <bot-name> <project-id> <source-file> <dist-file>

Running this command does the following:

1. Creates the Bot resource
2. Creates a ProjectMembership resource that connects it to a project
3. Saves the bot to the associated project in the Medplum database
4. Adds a bot entry to the medplum.config.json file in the bots array

Note

If you see an error, try running the command again. If it fails after 3 tries, please submit a bug report or contact us on Discord

After creating the bot, you should go to medplum.config.json and you should see the new bot added in the bottom of the file. It should look like this:

{
  "bots": [
    //…
    {
      "name": "my-first-bot",
      "id": "<BOT_ID>",
      "source": "src/my-first-bot.ts",
      "dist": "dist/my-first-bot.js"
    }
  ]
}

Parameter	Description
name	Name of the bot used in the Medplum CLI (below). Note: This name can be whatever your want. It does not have to match the filename of the bot code, nor anything in the Medplum App
id	The Bot Resource id. Can be found by navigating to app.medplum.com/Bot and clicking on the entry for the corresponding Bot. See the Bot Basics tutorial for more information
source	This is the location of the typescript source file for your bot. Note: Currently, Medplum only supports single-file Bots.
dist	This is the location of the transpiled javascript file for your bot. For most setups, this will be in your dist directory of your package.

Deploying your Bot

Now that your Bot is written and compiled, the resource is created, and your credentials are set, we can finally deploy our Bot to production using the Medplum CLI.

To deploy our bot, we will use the bot deploy command.

npx medplum bot deploy <bot-name>

Where <bot-name> is the name property that you set for your bot in medplum.config.json. In our example, this would be:

npx medplum bot deploy my-first-bot

Use a wild card * in <bot-name> to deploy multiple bots matching the pattern. This would allow us to deploy bots as part of a CI/CD pipeline, without having to update the command every time a new bot is added.

npx medplum bot deploy *staging*

Running this command does two things:

1. Save the TypeScript source to the code property of your Bot resource
2. Deploys your compiled Javascript code as an AWS Lambda function with your Medplum deployment.

Note

There is a known timing issue with the bot deploy command. If you see the following error, try running the command again. If it fails after 3 tries, please submit a bug report or contact us on Discord

Deploy error: {
resourceType: 'OperationOutcome',
issue: [ { severity: 'error', code: 'invalid', details: [Object] } ]
}

Deploying to Staging vs. Production

A common usage pattern is to set up two Medplum Projects for an application: A staging project for development and integration testing, and a production project to power workflows.

The same Bot source code can be deployed to multiple Medplum projects by creating two separate entries in medplum.config.json with different names, pointing to the same source/compiled files.

{
  "bots": [
    //…
    {
      "name": "my-first-bot-staging",
      "id": "<STAGING_BOT_ID>",
      "source": "src/my-first-bot.ts",
      "dist": "dist/my-first-bot.js"
    },
    {
      "name": "my-first-bot-production",
      "id": "<PRODUCTION_BOT_ID>",
      "source": "src/my-first-bot.ts",
      "dist": "dist/my-first-bot.js"
    }
    //...
  ]
}

To deploy the latest Bot to staging:

export MEDPLUM_CLIENT_ID=<STAGING_CLIENT_ID>
export MEDPLUM_CLIENT_SECRET=<STAGING_CLIENT_SECRET>
npm run build
npx medplum bot deploy my-first-bot-staging

To deploy the latest Bot to production:

export MEDPLUM_CLIENT_ID=<PRODUCTION_CLIENT_ID>
export MEDPLUM_CLIENT_SECRET=<PRODUCTION_CLIENT_SECRET>
npm run build
npx medplum bot deploy my-first-bot-production

This pattern is especially powerful when deploying Bots as part of a CI pipeline.

Configuring Bot Logging

Bots can be run at a very high volume - for example as part of an ADT feed or when triggered by high-frequency messages. This can result in thousands of invocations per day, which can be overwhelming to track. In these cases, it may make sense to fine-tune the level of logging for your Bots.

There are two ways to control Bot logging in Medplum: the type of event logged (i.e., success, failure, etc.) and where the event gets logged to.

Logging Triggers

You can choose to only log certain events using the Bot.auditEventTrigger field. This element represents the criteria for when an AuditEvent resource should be created and has four possible values.

Trigger	Description
always	An audit event is created and saved every time the bot runs. This is the default setting.
never	An audit event will never be saved by the bot.
on-error	An audit event is created and saved only if the bot throws an error.
on-output	An audit event is created and saved whenever the bot logs any output as part of its execution.

Logging Destination

Logging can also be limited by setting the destination that your Bot logs to. This is done using the Bot.auditEventDestination field. This element can be set to either resource or log.

By default, auditEventDestination is set to resource. This will create an AuditEvent resource in the main database, which can be accessed by Medplum's API and will be visibile in your app. However, the operation is slower and takes up more space. It is best practice to always start by using resource as it allows for easier testing and debugging of your Bot.

Setting auditEventDestination to log will only output an AuditEvent in your existing enterprise logging infrastructure, such as AWS Athena, Datadog, or others. This can make testing and debugging more difficult, but is quicker and useful for high-volume operations as it will fill up or slow down your main database.

Conclusion

As your Bots become more complex, integrating them into your software development workflow becomes crucial. Using the Medplum CLI allows you do integrate Bots into your regular code review process and deploy as part of your CI/CD pipelines.