Simple Python app working "like" DynamicDNS, checks every 15 minutes current public IP address with IP in provided DNS A record and if they are different updates record to the new one. If record doesn't exist yet you have to use create instead of patch method from google-api-python-client package and change app code in main.py a little bit

• Docker installed
• Service account JSON credentials generated in GCP with read/write privileges to Cloud DNS API (replace data in credentials.json file or change env variable GOOGLE_APPLICATION_CREDENTIALS to new file name)

In Dockerfile you have to change some environment variables to proper ones:

• GCP_PROJECT_ID
• GCP_DNS_ZONE
• GCP_A_RECORD
• GOOGLE_APPLICATION_CREDENTIALS

To build docker image:

• docker build -t gcp-dns-update .

To run docker container from image:

• docker run -itd gcp-dns-update

https://cloud.google.com/dns/docs/reference/v1/

For record set operations: https://cloud.google.com/dns/docs/reference/v1/resourceRecordSets/