Steps

The main things you need to get are:

Enable the API for the service you need
Create a Service Account for use in the deployment
Give the Service Account a sufficient role related to the API you want to access (You don’t have to do it at this point. This is something you can do later).
Generate and download the Service Account Private Key in JSON format.
Copy the contents of that JSON file into a protected environment variable in your CI/CD service of choice.
n your dev project, add an appropriate CI/CD YAML file depending on the requirements of your third party service.
An example YAML for Gitlab CI is shown below. But the concepts are universal.

Gitlab CI Example

Google provides a docker image already configured with gcloud. The image is google/cloud-sdk.

In this example, we will be build a docker image, save it to Container Registry and then deploy to Cloud Run.

Variables Needed

Variable	Value
GCP_SERVICE_KEY	{ Service Account Private Key }
GCP_PROJECT_ID	{ Project ID }

Resources/ APIs Needed

Cloud Build
Cloud Storage
Container Registry

Permissions/ Roles Needed by Service Account

Resource	Role	Path To Role
Cloud Build	Cloud Build Service Account	Service Agent Roles/ Cloud Build Service Account

Other Steps Needed

Create a storage bucket in Cloud Storage.
Create two folders. Namely:
- source - to store source files you send to Cloud Build
- logs - to store logs from build

The Config File

variables:
  APPLICATION_NAME: demo-application

image: google/cloud-sdk

build-image:
  scripts:
    - echo $GCP_SERVICE_KEY > $HOME/gcloud-service-key.json
    - gcloud auth activate-service-account --key-file $HOME/gcloud-service-key.json
    - rm $HOME/gcloud-service-key.json
    - gcloud --quiet config set project $GCP_PROJECT_ID
    - cloud builds submit . --tag gcr.io/$GCP_PROJECT_ID/$APPLICATION_NAME

How To Use gcloud in Third Party CI/CD Services Such As Circle CI and Gitlab CI