SAP Cloud Application Programming Model Getting Started (CAP)

Aus MattWiki

This article describes how to build Cloud Application Programming Model projects (CAP projects) and according artefacts with Core Data Services (CDS).

Source: ABAP Freak Show Ep. 1 - HANA Cloud and the Business Application Studio

https://www.youtube.com/watch?v=a3WPQwmpbvI&list=PLoc6uc3ML1JR38-V46qhmGIKG07nXwO6X&index=71

For local native development see SAP HANA Local Native Development

All-in-one Quick Start: https://github.com/SAP-samples/cloud-cap-walkthroughs/blob/master/exercises-node/intro/README.md

More Repositories: https://github.com/SAP-samples/cloud-cap-samples --> Use opensap*-Branches

Installation of Prerequisites

Relevant Tools from SAP 

npm i -g @sap/cds
npm i -g @sap/cds-dk

Additional 3rd Party Tools1 

npm i -g hana-cli

Create CDS Project

cds init bookshop

or 

cds init MyCDSProject --add hana, mta

Start Service

cds watch

This also monitors changes to the underlying files and restarts when a file has changed.

Create Persistency from CDS

cds deploy --to sqlite          # Deploys to sqlite.db
cds deploy --to sqlite:my.db    # Deploys to my.db
cds deploy --to hana            # Deploys to HDI container on HANA
                                # (Requires Cloud Foundry login)

This also updates the package.json

Deployment to sqlite requires node module sqlite3. To install it execute in the root of the project folder: 

npm install sqlite3

In order to see the actual created SQL statements: 

cds compile srv/cat-service.cds --to sql     # Creates SQL statements
cds compile srv/cat-service.cds --to hana    # Creates hdbcds or hdbtable/hdbview artefacts

Deployment to SAP Business Technology Platform (BTP)

Login to CF space: 

cf login

Build Deployment Package

cds add hana

package.json needs to contain "kind": "hana". (really? - for which CF / HANA Cloud Version?)

Also when deploying to BTP which is internally HANA 4.0 "deploy-format": "hdbtable" has to be set and hdi-deploy should be at least version 4. Example: 

{
    ...
    "devDependencies": {
        "@sap/hdi-deploy": "^4"
    },
    ...
    "cds": {
        "hana": {
            "deploy-format": "hdbtable"
        },
        "requires": {
            "db": {
                "model": [
                    "db",
                    "srv"
                ],
                "kind": "hana"
            }
        }
    }
}

Deploy via Cloud Foundry CLI

Build the deployment artifacts: 

cds build/all

Create a hana service for the hdi-container. The stated hdi-container name must correlate to the services-name in /gen/db/src/manifest.yaml. 

cf create-service hana hdi-shared <app-db-hdi-container>

Now push the DB deployer application and also the actual service application: 

cf push -f gen/db
cf push -f gen/srv --random-route

Deploy via MTA

Install MTA Build Tool 

npm install -g mbt

Generate MTA project descriptor file mta.yaml and build MTA archive: 

cds add mta
mbt build

Deploy MTA archive to CF space: 

cf deploy mta_archives/<buildmta>.mtar

Troubleshooting

Real-time output of CF services can be displayed in BAS terminal with 

cf logs <appname>
Abgerufen von „https://otremba.net/w/index.php?title=SAP_Cloud_Application_Programming_Model_Getting_Started_(CAP)&oldid=2785“