Create a topic and subscription for gcp pubsub local emulator, idempotently

prep_gcp_local.bash

#!/usr/bin/env bash

# Exit immediately if a command exits with a non-zero status.
set -e
# Treat unset variables as an error and exit immediately.
set -u
# Return the exit status of the last command in the pipeline that failed.
set -o pipefail

PROJECT_ID="MYPROJECT"
TOPIC_ID="MYTOPIC"
SUBSCRIPTION_ID="MYSUB"

# We want maximum time since backfill can be slow potentially
ACK_DEADLINE_SECONDS=600

PROJECT_URL="http://$PUBSUB_EMULATOR_HOST/v1/projects/${PROJECT_ID}"

create_topic() {
  curl -X PUT \
  -H "Content-Type: application/json" \
  "$PROJECT_URL/topics/${TOPIC_ID}"

  echo "Topic '${TOPIC_ID}' created successfully."
}

create_subscription() {
  curl -X PUT \
  -H "Content-Type: application/json" \
  -d "{
    \"topic\": \"projects/${PROJECT_ID}/topics/${TOPIC_ID}\",
    \"ackDeadlineSeconds\": ${ACK_DEADLINE_SECONDS}
  }" \
  "$PROJECT_URL/subscriptions/${SUBSCRIPTION_ID}"

  echo "Subscription '${SUBSCRIPTION_ID}' created successfully."
}

# Check if the topic already exists
if curl -s "$PROJECT_URL/topics/${TOPIC_ID}" | grep -q "${TOPIC_ID}"; then
  echo "Topic '${TOPIC_ID}' already exists."
else
  create_topic
fi

# Check if the subscription already exists
if curl -s "$PROJECT_URL/subscriptions/${SUBSCRIPTION_ID}" | grep -q "${SUBSCRIPTION_ID}"; then
  echo "Subscription '${SUBSCRIPTION_ID}' already exists."
else
  create_subscription
fi