CI/CD

• CI/CD architecture:
• Branching architecture:
• Code pipeline:
• Each pipeline has stages
• Each pipeline should be linked to a single branch in a repository
• CodeBuild/CodeDeploy configuration files:
  • buildspec.yml, appspec.[yml|json]
  • Reference to these files: https://docs.aws.amazon.com/codedeploy/latest/userguide/reference-appspec-file.html
  • buildspec is used to influence the way the build process occurs within CodeBuild
  • appspec allows the influence how the deployment process proceeds in CodeDeploy

AWS CodeCommit

• Managed git service
• Basic entity of CodeCommit is a repository
• Authentication can be configured via IAM console. CodeCommit supports HTTPS, SSH and HTTPS over GRPC
• Triggers and notifications:
  • Notifications rules: can send notifications based on events happening in the repo, example: commits, pull request, status changes, etc. Notifications can be sent to SNS topics or AWS chat bots
  • Triggers: allow the generate event driven processes based on things that happen in the repo. Events can be sent ot SNS or Lambda functions

AWS CodePipeline

• It is a Continuos Delivery Tools
• Controls the flow from source code, through build towards deployment
• A pipeline is build from stages. These contain actions which can be sequential or parallel
• Movement between stages can happen automatically or it can require a manual approval
• Action can consume artifacts or they can generate artifacts
• Artifacts are just files which are generated and/or consumed by actions
• Any changes to the sate of pipelines, stages or actions generate events which are published to Event Bridge
• CloudTrail or Console UI can be used to view/interact with the pipeline

AWS CodeBuild

• CodeBuild is a build as a service product
• It is fully managed, we pay only for the resources consumed during builds
• CodeBuild is an alternative to the solutions provided by third party solutions such as Jenkins
• CodeBuild uses Docker for build environments which can be customized by us
• CodeBuild integrates with other AWS services such as KMS, IAM, VPC, CloudTrails, S3, etc.
• Architecturally CodeBuild gets source material from GitHub, CodeCommit, CodePipeline or even S3
• It builds and tests code. The build can be customized via buildspec.yml file which has to be located in the root of the source
• CodeBuild output logs are published to CloudWatch Logs, metrics are also published to CloudWatch Metrics and events to Event Bridge (or CloudWatch Events)
• CodeBuild supports build environments such as Java, Ruby, Python, Node.JS, PHP, .NET, Go and many more

buildspec.yml

• It is used to customize the build process
• It has to be located in root folder of the repository
• It can contain four main phases:
  • install: used to install packages in the build environment
  • pre_build: sign-in to things or install code dependencies
  • build: commands run during the build process
  • post_build: used for packaging artifacts, push docker images, explicit notifications
• It can contain environment variables: shell, variables, parameter-store, secret-manager variables
• Artifacts part of the file: specifies what stuff to put where

AWS CodeDeploy

• Is a code deployment as a service product
• It is an alternative for for third-party services such as Jenkins, Ansible, Chef, Puppet and even CloudFormation
• It is used to deploy code, not resources (use CloudFormation for that)
• CodeDeploy can deploy code to EC2, on-premises, Lambda and Ecs
• Besides code, it can deploy configurations, executables, packages, scripts, media and many more
• CodeDeploy integrates with other AWS services such as AWS Code*
• In order to deploy code on EC2 and on-premises, CodeDeploy requires the presence of an agent

appspec.[yaml|json]

• It controls how deployments occur on the target
• Manages deployments: configurations + lifecycle event hooks
• Configuration section:
  • Files: applies to EC2/on-premises. Provides information about which files should be installed on the instance
  • Resources: applies to ECS/Lambda. For Lambda it contains the name, alias, current version and target version of a Lambda function. For ECS contains things like the task definition and container details (ports, traffic routing)
  • Permissions: applies to EC2/on-premises. Details any special permissions and how should be applies to files and folders from the files sections
• Lifecycle event hooks:
  • ApplicationStop: happens before the application is downloaded. Used for gracefully stop the application
  • DownloadBundle: agent copies the application to a temp location
  • BeforeInstall: used for pre-installation tasks
  • Install: agent copies the application from the temp folder to the final location
  • AfterInstall: perform post-install steps
  • ApplicationStart: used to restart/start services which were stopped during the ApplicationStop hook
  • ValidateService: verify the deployment was completed successfully