Reference implemention of the concepts discussed in the presentation - https://chitamoor.github.io/docker-dx/
An appliation stack typically has three components -
- A primary service
- A DataStore e.g. Postgres DB (some services may not have a Datastore)
- Zero or more secondary services
All of the above components (services) run inside a Docker container. There exists a separate Dockerfile for the primary service and the DB service. All the dependent services are declared in the docker-compose.yml file. Please see the Docker Setup section for specific instructions on how to set up Docker
Each of the application stack's components (primary service, DB service and dependent services) have one or more of the following lifecycle stages -
- init (env)
- build (image)
- start/restart (contaniner)
- destroy (contaniner and image)
In order to launch the application stack, you will need the docker images for the primary, DB and dependent services. You can only build the (docker) image for the primary service and the corresponding DB service from within a repo/project. The images of dependent services can either be pulled from the private repository or can be built locally from within the corresponding repo/project.
devctl.sh is the primary (bash) script that controls the developer environment, including the lifecyle of the application stack. The devctl script is found in the main directory of every project, and requires a few environment variables to be specified. These variables must be defined in the env.sh file which should also exist in the top level directory of the project.
Examples of the variables that need to be defined in env.sh -
export SERVICE="docker_dx/xxx”
export SERVICE_NAME=“xxx”
export DB_SERVICE=${SERVICE}-db
export DB_SERVICE_IMAGE=${SERVICE_IMAGE}-db
export REGISTRY_URL=docker.*
devctl.sh init
init command calls the init.sh script if it exists. So, if your project needs any initialization/setup, you will have to define it in ```init.sh`` script in the top level directory of the project.
###Primary service lifecycle commands
-
Build the primary service Image - Creates the Docker Image needed for the primary service
devctl.sh build-serviceThe build command only applies to the primary service
If you need to build the images of the dependent services, you will have to checkout the repo of the corresponding dependent service and build the images separately. You can alternatively, pulls the images from the Private Registry as well. The build command should be called any time you make changes to the source code or config changes
-
Start a Service - Start a service. See below for the list of Services
devctl.sh start-service <service_name>If you don't specify a service, the primary service will be used
-
Stop a Service - Stop a service. See below for the list of O2I-Services
devctl.sh stop-service <service_name>If you don't specify a service, the primary service will be used
-
Restart a Service - Restart a service. Look below for the list of service names.
devctl.sh restart-service <service_name>If you don't specify a service, the primary service will be used
-
Build the DB Service Image - Creates the Docker Image needed for the DB service
devctl.sh build-dbPlease see the DB Setup section for further information -
Start the DB Service - Start the DB service
devctl.sh start-db -
Stop the DB Service - Stop the DB service
devctl.sh stop-db -
Restart the DB Service - Restart the DB service
devctl.sh restart-db
-
Launch Stack - Start the primary service and all the dependent services
devctl.sh start-stack
-
Shutdown Stack - Stop the primary service and all the dependent services
devctl.sh stop-stack -
Restart Stack - Re-start the primary service and all the dependent services
devctl.sh restart-stack
-
Cleanup - Remove dangling images
devctl cleanup -
Status - Shows the status of the containers including exited containers
devctl status -
ps - Shows the status of the running containers
devctl ps
The specific properties for each of the service is defined in the "env.sh" file for each project
- Container/Primary-Service Name: primary_svc
- DataBase Container/Service: primary_svc-db
- DataBase Name : primary_svc
- Container/Primary-Service Name: micro_svc_one
- DataBase Container/Service: micro_svc_one-db
- DataBase Name : micro_svc_one
- Container/Primary-Service Name: micro_svc_two
- All of the Docker related files are in the top level docker folder inside every project.
- The docker-compose.yml file is in the docker directory
- There are two docker files -
- One for the Application - docker/application/Dockerfile
- One for the DB - docker/database/Dockerfile
You will have to run devctl.sh build-service for each of the services - primary, micro_service_one and micro_service_two
You will have to run devctl.sh build-data from within the - primary_service and micro_service_one directories
Run devctl.sh start-stack from inside the primary_service directory
Run devctl.sh status to verify if all the containers/services started properly
- http://localhost:9000/api/primary/
- http://localhost:9000/api/primary/micro_one
- http://localhost:9000/api/primary/micro_one/resource/1
- http://localhost:9000/api/primary/micro_two
There exists a seed.sql file inside the docker/database directory. This file is generated through the generate_db_seed.sh script. The generate_db_seed.sh basically runs the liquibase definitions in the liquibase/seed and liquibase/migrations directories.
devctl.sh build-db command creates a Postgres Docker image and initializes it with the seed.sql file.