AWS lambda function throwing error "newPromise is not defined" - node.js

Question

I am using AWS lambda function with below code
'use strict';
var newPromise = require('es6-promise').Promise;
const childProcess= require("child_process");
const path= require("path");
const backupDatabase = () => {
const scriptFilePath =path.resolve(__dirname, "./backup.sh");
return newPromise((resolve, reject) => {
childProcess.execFile(scriptFilePath, (error) => {
if (error) {
console.error(error);
resolve(false);
}
resolve(true);
});
});
};
module.exports.handler = async (event) => {
const isBackupSuccessful = await backupDatabase();
if (isBackupSuccessful) {
return {
status: "success",
message: "Database backup completed successfully!"
};
}
return {
status: "failed",
message: "Failed to backup the database! Check out the logs for more details"
};
};
The code above run's with in the docker container, tries to run the below backup script
#!/bin/bash
#
# Author: Bruno Coimbra <bbcoimbra#gmail.com>
#
# Backups database located in DB_HOST, DB_PORT, DB_NAME
# and can be accessed using DB_USER. Password should be
# located in $HOME/.pgpass and this file should be
# chmod 0600[1].
#
# Target bucket should be set in BACKUP_BUCKET variable.
#
# AWS credentials should be available as needed by aws-cli[2].
#
# Dependencies:
#
# * pg_dump executable (can be found in postgresql-client-<version> package)
# * aws-cli (with python environment configured execute 'pip install awscli')
#
#
# References
# [1] - http://www.postgresql.org/docs/9.3/static/libpq-pgpass.html
# [2] - http://docs.aws.amazon.com/cli/latest/userguide/cli-chap-welcome.html
#
#
###############
### Variables
export AWS_ACCESS_KEY_ID=
export AWS_SECRET_ACCESS_KEY=
DB_HOST=
DB_PORT="5432"
DB_USER="postgres"
BACKUP_BUCKET=
###############
#
# **RISK ZONE** DON'T TOUCH below this line unless you know
# exactly what you are doing.
#
###############
set -e
export PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
### Variables
S3_BACKUP_BUCKET=${BACKUP_BUCKET:-test-db-backup-bucket}
TEMPFILE_PREFIX="db-$DB_NAME-backup"
TEMPFILE="$(mktemp -t $TEMPFILE_PREFIX-XXXXXXXX)"
DATE="$(date +%Y-%m-%d)"
TIMESTAMP="$(date +%s)"
BACKUPFILE="backup-$DB_NAME-$TIMESTAMP.sql.gz"
LOGTAG="DB $DB_NAME Backup"
### Validations
if [[ ! -r "$HOME/.pgpass" ]]; then
logger -t "$LOGTAG" "$0: Can't find database credentials. $HOME/.pgpass file isn't readable. Aborted."
exit 1
fi
if ! which pg_dump > /dev/null; then
logger -t "$LOGTAG" "$0: Can't find 'pg_dump' executable. Aborted."
exit 1
fi
if ! which aws > /dev/null; then
logger -t "$LOGTAG" "$0: Can't find 'aws cli' executable. Aborted."
exit 1
fi
logger -t "$LOGTAG" "$0: remove any previous dirty backup file"
rm -f /tmp/$TEMPFILE_PREFIX*
### Generate dump and compress it
logger -t "$LOGTAG" "Dumping Database..."
pg_dump -O -x -h "$DB_HOST" -p "$DB_PORT" -U "$DB_USER" -w "$DB_NAME" > "$TEMPFILE"
logger -t "$LOGTAG" "Dumped."
logger -t "$LOGTAG" "Compressing file..."
nice gzip -9 "$TEMPFILE"
logger -t "$LOGTAG" "Compressed."
mv "$TEMPFILE.gz" "$BACKUPFILE"
### Upload it to S3 Bucket and cleanup
logger -t "$LOGTAG" "Uploading '$BACKUPFILE' to S3..."
aws s3 cp "$BACKUPFILE" "s3://$S3_BACKUP_BUCKET/$DATE/$BACKUPFILE"
logger -t "$LOGTAG" "Uploaded."
logger -t "$LOGTAG" "Clean-up..."
rm -f $TEMPFILE
rm -f $BACKUPFILE
rm -f /tmp/$TEMPFILE_PREFIX*
logger -t "$LOGTAG" "Finished."
if [ $? -eq 0 ]; then
echo "script passed"
exit 0
else
echo "script failed"
exit 1
fi
I created a docker image with above app.js content and bakup.sh with the below docker file
ARG FUNCTION_DIR="/function"
FROM node:14-buster
RUN apt-get update && \
apt install -y \
g++ \
make \
cmake \
autoconf \
libtool \
wget \
openssh-client \
gnupg2
RUN wget --quiet -O - https://www.postgresql.org/media/keys/ACCC4CF8.asc | apt-key add - && \
echo "deb http://apt.postgresql.org/pub/repos/apt/ buster-pgdg main" | tee /etc/apt/sources.list.d/pgdg.list && \
apt-get update && apt-get -y install postgresql-client-12
ARG FUNCTION_DIR
RUN mkdir -p ${FUNCTION_DIR} && chmod -R 755 ${FUNCTION_DIR}
WORKDIR ${FUNCTION_DIR}
COPY package.json .
RUN npm install
COPY backup.sh .
RUN chmod +x backup.sh
COPY app.js .
ENTRYPOINT ["/usr/local/bin/npx", "aws-lambda-ric"]
CMD ["app.handler"]
I am running the docker container created with the image created from the above docker file
docker run -v ~/aws:/aws -it --rm -p 9000:8080 --entrypoint /aws/aws-lambda-rie backup-db:v1 /usr/local/bin/npx aws-lambda-ric app.handler
And trying to hit that docker container with below curl command
curl -XPOST "http://localhost:9000/2015-03-31/functions/function/invocations" -d '{}'
when I run curl command I am seeing the below error
An error I see is :"newPromise is not defined","trace":["ReferenceError: newPromise is not defined"," at backupDatabase (/function/app.js:9:3)","
Tried adding the variable var newPromise = require('es6-promise').Promise;, but that gave a new error "Cannot set property 'scqfkjngu7o' of undefined","trace"
Could someone help me with fixing the error ? My expected output is the message as described in the function, but am seeing the errors.
Thank you

Answer 1

Node 14 supports promises natively. You should do:
return new Promise((resolve, reject) => {
childProcess.execFile(scriptFilePath, (error) => {
if (error) {
console.error(error);
resolve(false);
}
resolve(true);
});
Note the space between new and Promise. Promise is the object and you are using a constructor. There is no need to import any module.