applications

Create a new applicaton

Any Dockerfile added in a subfolder below the applications directory is interpreted as an application part of the deployment.

Use harness-application

The harness-application cli tool creates new applications from predefinite code templates. To create a new Flask base microservice application, run:

harness-application myapp

Other examples:

Create a web application

harness-application myapp -t webapp

Create a web application with Mongo database

harness-application myapp -t webapp -t db-mongo

For more info, harness-application --help

Manual application creation

1. Add the application inside applications/[APPLICATION_NAME] with a Dockerfile in it
2. Define deploy/values.yaml inside the file in order to specify custom values for the application
3. (optional) Define specific helm template variables on deploy/values.yaml
4. (optional) Define the helm templates for the application inside deploy/templates (if any). In the helm template, it is recommended to use the automatically generated values from the values.yaml. The path of the variables will be .Values.myapp.myvariable
5. Run harness-deployment

Use Openapi to generate REST microservices and web applications

The preferred way to define an application is through the openapi specification. The code for the Python-flask service and the Python client are automatically generated with the script harness-generate

1. Add the application inside applications/[APPLICATION_NAME]
2. Add the openapi yaml specification inside applications/[APPLICATION_NAME]/api/[APPLICATION_NAME].yaml
3. Define openapi configuration applications/[APPLICATION_NAME]/api/config.json. The name of the package (say, PACKAGE_NAME) can be configured here. By convention, the package name is [APPLICATION_NAME]
4. Run harness-generate . to generate code stubs

The only code that should be modified shall go inside src/[PACKAGE_NAME]/controllers. After modifying the controllers, add the following line to .openapi-generator-ignore:

*/controllers/*
Dockerfile

Define an application without openapi

1. Add the application inside applications/[APPLICATION_NAME] with a Docker file in it. The Docker file must inherit from cloudharness-base in order to get access to cloudharness libraries.
2. Define values.yaml inside the file in order to specify custom values for the application

From existing external image

To use an external image using the default deployment generator from Cloudharness, define the image inside applications/my-external-app/deploy/values.yaml file.

harness:
  deployment:
    auto: true
    image: nginx:1.0.0

To customize the helm templates to use, put them inside the deploy subdirectory.

Dependency to an existing Helm chart

TBD

Dependency to a custom Helm chart

TDB

Harness values and automatic templates

Cloud-harness creates a series of artifacts and configurations for each application, depending on the values defined on the deploy/values.yaml file inside the application

Given an application on applications/myapp, the values file is located at applications/myapp/deploy/values.yaml.

The most important configuration entries are the following:

• harness: root of all auto templates configurations
  • subdomain: creates an entry to ingress on [subdomain].[Values.domain]
  • domain: creates an entry to ingress on [domain]
  • secured: if set to true, shields the access to the application requiring login
  • uri_role_mapping ({uri, roles}[]): if secured is true, used to map application urls to authenticated required roles
  • deployment: creates a deployment
    • auto: if true, creates the deployment automatically
    • resources: define cpu and memory limits
    • volume: application persistent volume
  • service:
    • auto: if true, creates the service automatically
  • dependencies: lists of applications/images this application depends from
    • hard: hard dependencies mean that they are required for this application to work properly
    • soft: the application will function for most of its functionality without this dependency
    • build: the images declared as build dependencies can be referred as dependency in the Dockerfile
    • git: specify repos to be cloned before the container build
  • database: automatically generates a preconfigured database deployment for this application
    • auto: if true, turns on the database deployment functionality
    • type: one from postgres (default), mongo, neo4j
    • postgres: postgres specific configurations
    • mongo: mongo specific configurations
    • neo4j: neo4j specific configurations
  • envmap: add custom environment variables
    • <environment_variable_name>: <environment_variable_value>
    • ...
  • env ({name, value}[]): add custom environment variables (deprecated, please use envmap)
  • resources: mount files from
  • use_services ({name, src, dst}[]): create reverse proxy endpoints in the ingress for the listed applications on [subdomain].[Values.domain]/proxy/[name]. Useful to avoid CORS requests from frontend clients
  • readinessProbe: defines a a url to use as a readiness probe
  • livenessProbe: defines a a url to use as a liveness probe
  • dockerfile: configuration for the dockerfile, currently only implemented in Skaffold
    • buildArgs: a map of build arguments to provide to the dockerfile when building with Skaffold

Example code

• Sample application is a sample web application providing working examples of deployment configuration, backend and frontend code.