execSync throws and error trying to run node - node.js

Question

I am running some processes inside of an EC2 instance.
To run it I initiate it with an SSM command:
cd / && cd home/ec2-user && . .nvm/nvm.sh && cd ufo && npm run start
and inside of it, I have a method in app.ts which is initialized with ts-node app.ts
import { execSync } from 'node:child_process';
import { takeNextScheduledAudit } from './sqs-scheduler';
import { uploadResultsToBucket } from './s3-uploader';
import { AuditRunParams } from "./types";
import { sendAuditResults } from "./sendResults";
(async function conductor(): Promise<void> {
const nextAuditRunParams = await takeNextScheduledAudit();
if (!nextAuditRunParams) {
execSync("sudo shutdown -h now");
}
const { targetUrl, requesterId, endpoint } = nextAuditRunParams as AuditRunParams;
try {
execSync(`npx user-flow --url=${targetUrl} --open=false`);
const resultsUrl = await uploadResultsToBucket(targetUrl);
await sendAuditResults(requesterId, endpoint, resultsUrl);
} catch (error) {
console.log(error);
}
await conductor();
})();
If I log in manually and run npm run start the scripts works as intended but if I run it using the SSM command I get this output:
> start
> ts-node app.ts
Error: Command failed: npx user-flow --url=https://deep-blue.io/ --open=false
at checkExecSyncError (node:child_process:841:11)
at execSync (node:child_process:912:15)
at conductor (/home/ec2-user/ufo/app.ts:15:17)
at processTicksAndRejections (node:internal/process/task_queues:96:5) {
status: 243,
signal: null,
output: [ null, <Buffer >, <Buffer 0a> ],
pid: 2691,
stdout: <Buffer >,
stderr: <Buffer 0a>
}
and this error:
Error: Command failed: sudo shutdown -h now
at checkExecSyncError (node:child_process:841:11)
at execSync (node:child_process:912:15)
at conductor (/home/ec2-user/ufo/app.ts:10:17)
at processTicksAndRejections (node:internal/process/task_queues:96:5)
at async conductor (/home/ec2-user/ufo/app.ts:21:5) {
status: null,
signal: 'SIGTERM',
output: [ null, Buffer(0) [Uint8Array] [], Buffer(0) [Uint8Array] [] ],
pid: 2705,
stdout: Buffer(0) [Uint8Array] [],
stderr: Buffer(0) [Uint8Array] []
}
failed to run commands: exit status 1
Moreover, if I run execSync("node -v && npx -v") it also throws an error.
Why can I run this script when i am logged in but if i run it via a SSM command it does not recognize node inside of node?
--- Edit - Added Info ---
When running execSync(node -v && npx -v,{shell: '/bin/bash'}) I get an error:
Error: Command failed: node -v && npx -v
When running execSync(ps -p $$ && echo $SHELL, {shell: '/bin/bash'}):
PID TTY TIME CMD
7817 ? 00:00:00 bash
/bin/bash
And when I loggin and do ps -p $$ && echo $SHELL I get:
PID TTY TIME CMD
6873 pts/0 00:00:00 bash
/bin/bash

Answer 1

By default, all of the child_process functions execute in the same environment as the process that launched them. I don't have an account handy to test with, but it's quite likely that SSM skips over a traditional shell and just executes certain runtimes directly.
You can use the exec options like this to set a particular shell in which to launch the process:
const output = execSync('echo "doing stuff"', {
shell: '/bin/bash',
})
console.log('***** output:', output.toString())
This is assuming the OS you're using for the EC2 instance has bash available. Most flavors of linux should, but for what you're doing there, /bin/sh is sufficient if not. To get a list of the available shells, you can run:
cat /etc/shells
## or possibly
sudo cat /etc/shells
EDIT: Since you say it works fine in a shell already, you have presumably already handled this, but user-flow would also have to be available. It's not a module from npmjs, so would need to already be present on the box as either a local dependency or a private repo to which the EC2 instance has access.