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    Command-Line Interface (CLI)

    Installed with @sap/cds-dk

    To use cds from your command line install @sap/cds-dk globally:

    npm i -g @sap/cds-dk
    

    cds version

    • Use cds version to get information about your installed package version

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    cds help

    • Use cds help to see an overview of all commands

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    • Use cds help <command> or cds <command> ? to get specific help

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    cds init/add

    • Use cds init to create new projects
    • Use cds add to gradually add features to projects

    cds env

    • Use cds env to inspect currently effective config settings

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    cds repl

    • Use cds repl to live-interact with Node.js APIs

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    Debugging with cds watch

    Start cds watch and enter debug. This restarts the application in debug mode. Similarly, debug-brk will start debug mode, but pause the application at the first line, so that you can debug bootstrap code.

    If you do this in VS Code’s integrated terminal with the ‘Auto Attach’ feature enabled, debugging starts right away: Debug with cds watch

    If you executed cds watch on a standalone terminal, you can still attach a Node.js debugger to the process.

    For example:

    • In VS Code, use the Debug: Attach to Node Process command.
    • In Chrome browser, just open chrome://inspect and click Inspect.

    Visual Studio Code

    Install Visual Studio Code

    1. Install Visual Studio Code and launch it.
    2. Only for macOS: Install the code shell command.

    Add CDS Editor

    1. Go to Visual Studio Marketplace.
    2. Choose Install and VS Code opens the details page for the extension SAP CDS language support.
    3. In VS Code, choose Install to enable the extension.

    Learn more about the CDS Editor.

    Run Services

    To run services, just open the Integrated Terminal in VS Code and use one of the cds serve variants, for example, use cds watch to automatically react on changes.

    Alternatively, you can use the preconfigured tasks or launch configurations you get when creating a project with cds init. For example, in the Debug view launch cds run with the green arrow button:

    Debug Services

    You can add and stop at breakpoints in your service implementations. For example, add one to line 10 of our srv/cat-service.js by clicking in the gutter as shown here:

    … then send the …/Books request again to stop there.

    Restart the Server

    Restart the server when you did changes to your code using the Debug views restart button:

    Eclipse

    Prerequisites

    Docker

    Prerequisites

    Build an Image

    Create a file called Dockerfile and add this content for a quick setup:

    FROM node:lts-alpine
    # or use `FROM node:12.18.1` for example to match a specific Node
    # version you have installed locally
    
    RUN apk add python
    
    USER node
    ENV NPM_CONFIG_PREFIX=/home/node/.npm
    ENV PATH=$NPM_CONFIG_PREFIX/bin:$PATH
    
    RUN npm i -g @sap/cds-dk
    

    Build your first image:

    docker build -t cds .
    

    If you experience issues building that image, replace the first line FROM node:lts-alpine with FROM node:12.18.1-alpine3.10 as this version has been successfully tested.

    Run a Service in a Container

    1. Run a container that is based on the image:
      docker run --publish 4004:4004 -it cds sh
      

      You see a $ command prompt from inside the container.

    2. Move to the home directory:
      cd
      
    3. Write a simple cds file:
      echo 'service CatalogService { entity Books { key ID: UUID; } }' \
       > services.cds
      
    4. Run the service:
      cds run
      
    5. Open http://localhost:4004 in a browser to test the application. You forwarded the port 4004 when running the container, which allows you to access the application as if it would run locally.

    CDS Editors & LSP

    The editor powered by the CDS language server implementation, provides source code validation including diagnostics, like error messages and warnings.

    The following features are available for all editors based on our language server implementation for CDS in SAP Business Application Studio, Visual Studio Code, and Eclipse. The plugins are available for download for Visual Studio Code at Visual Studio Marketplace and for Eclipse at SAP Development Tools.

    Short video about the SAP CDS language support extension for VS Code in action by DJ Adams.

    Features and Functions

    Syntax highlighting

    Code completion

    • Keywords
    • Identifiers including not yet imported identifiers with corresponding using statement
    • Using paths and artifacts including showing README.md documentation as details
    • i18n translation IDs
    • Turn on/off formatting regions

    Where-used navigation

    • Navigate to definitions
    • Navigate to references
    • Highlight occurrences

    QuickFixes

    • Create using statement for unknown artifacts.
    • Maintain missing translation.
    • Convert @cds.doc and @description annotations to doc comments.

    Code formatting

    Format…

    • the whole document
    • a selected range
    • on-the-fly when completing statements using ; or }
    • on save (depending on the IDE)
    • on paste (depending on the IDE)

    Use…

    • many options, configurable using
      • settings file
      • command line switches
      • config UI with simulation of options for VS Code and Eclipse
      • JSON schema for textual support
    • also for markdown in doc comments

    Inventory (symbols)

    • An inventory for the current file.
    • An inventory for the workspace including query capabilities to select. For example, artifact types, names, also include reuse models.

    Snippets for typical CDS language constructs

    • Namespace and context
    • using
    • service
    • type
    • Entity and projections, …
    • Element, associations, and compositions
    • Extend and annotate
    • Annotations for documentation

    With documentation extracts of capire explaining language concepts.

    Hover information based on

    • Doc comments
    • @title, @description, and @cds.doc (deprecated) annotations
    • Translations

    Translation support

    • Properties, JSON, and CSV files
    • Navigate to translation definitions from translation IDs like '{i18n>customerName}'.
    • Show translations on hover.
    • Quickfix to maintain missing translations

    And more

    • Plugin framework for external handlers of annotation domains

    Settings

    Code formatting settings
    These are settings coming with the CDS language server implementation. Use the command CDS: Show Formatting Options Configuration. You see the settings, grouped into three tabs: Alignment, Other, and Whitespace

    Format on Type, Format on Paste, and Format on Save in VS Code
    These are settings from the editor in VS Code:

    1. Press F1
    2. Open Preferences: Open User Settings
    3. Filter for Format.
    4. Tick the checkboxes to enable the settings.

    Cds: Workspace Validation Mode

    Default: ActiveEditorOnly

    Keeps track of the active editor in focus. Only changes there are immediately validated.

    The ActiveEditorOnly mode is especially useful in situations when navigating through a large model, that is having multiple files open (even if they are not shown as tabs) and editing a file that the others directly or indirectly depend on.

    If switched to OpenEditorsAndDirectSources all model files on every change, for example typed character, are recompiled.
    If switched to OpenEditorsOnly all open files, for example split tabs, are recompiled.
    For large models, this can lead to high CPU load and high memory load and consequently weak responsiveness of the editor.

    Cds > Contributions > Enablement: Odata

    Default: on

    This setting enables extended support for annotations, that is refined diagnostics and code completion. Can be switched off for performance gains.

    Cds > Workspace: ScanCsn

    Default: off

    Switch on to scan the workspace also for CSN files, additionally to CDS source files.

    Note: CSN files are still considered if used from a CDS source file.

    Cds > Quickfix: ImportArtifact

    Default: off

    Enable to get quickfix proposals for artifact names, like entities, that aren’t imported via a using statement. For that, all definitions in the workspace need to be considered, which might be slow.

    Commands

    Welcome page

    1. Press F1
    2. Open CDS: Show CAP Release Notes

    If there are new release notes, this page opens on startup. You can disable this behavior using the CDS > Release Notes: Show Automatically (cds.releaseNotes.showAutomatically) setting.

    Beautify settings

    1. Press F1
    2. Open CDS: Show Formatting Options Configuration

    Preview CDS sources

    You want to create a preview of a specific .cds file in your project. You can do that using the command line. Here is how you do it in VS Code:

    1. Open the file you want to preview.
    2. Open the context menu.
    3. Select Preview CDS source as… .
    4. Choose the preview you want to see.

    Visualize CDS file dependencies

    Use the command from the context menu on a folder or CDS file.

    A selection popup appears to choose one of three modes:

    1. File to file (detailed)
    2. File to file (reduced to folders)
    3. Complete folder to complete folder

    The first option shows every model file on its own. For very large models, the number of files and interdependencies may be too complex to be graphically shown. A message about insufficient memory will appear. In this case use the second option.

    The second option reduces the graph by only showing the folders of all involved files and their interdependencies.

    Only those files are evaluated that are reachable from the start model where the command was invoked on.

    The third option always considers all files in a folder and their dependencies. This can be useful to understand architectural violations.

    Example for architectural violation:
    You want a clean layering in your project: app -> srv -> db. With this option, you can visualize and identify that there is a dependency from a file in the service layer to an annotation file in the application layer.

    Hovering over a node will show the number of files involved and the combined size of all involved files. Use this function to get a rough understanding about the complexity and the compilation speed.

    The command requires the third-party extension Graphviz (dot) language support for Visual Studio Code (joaompinto.vscode-graphviz). If you haven’t installed it already, it will be suggested to install.

    Editor Performance

    With the following settings you can influence the performance of the editor:

    Editor > Goto Location: Alternative Definition Command

    Do not select goToReferences. Otherwise, being already on a definition often requires all models to be recompiled.

    Workbench > Editor > Limit: Value

    If open editors have using dependencies, a change in one editor will lead to a recompile of related editors. To decrease the impact on performance, lower the number.

    Workbench > Editor > Limit: Enabled

    To enable the limit value above, switch on.

    In addition, here are some hints to increase performance:

    • Within SAP Business Application Studio: close CAP Data Models and Services view. Otherwise, it will ask for all workspace symbols at every change.
    • Commands Go to References / Find All References will recompile all models that might have changed due to a change in a depending model. If there are index models, it often means that the complete workspace is being recompiled. Until a further change, reference calculation is reasonably fast.
    • Command Go to Symbol in Workspace will recompile the complete workspace once, after that it is reasonable fast.
    • Changing settings in CDS section will currently perform a complete workspace invalidation i.e. required indexes will lead to recompilations on demand as described above.
    • Changing certain cds.env settings, for example folder configurations, will invalidate the workspace as well.

    CDS Lint & ESlint

    To catch issues with CDS models and the CDS environment early, CAP provides an ESLint plugin with a set of recommended rules. Together with the lint client of the @sap/cds-dk, this comprises CDS Lint.

    Usage via cds CLI

    In your project’s root folder, execute:

    cds lint .
    

    If there are no lint errors, there is no output. Otherwise, a standard ESLint error report will be printed.

    Editor Integration

    1. Download the standard ESLint extension for Visual Studio Code. CDS Lint seamlessly integrates with it. For SAP Business Application Studio this is preinstalled.

    2. Configure our recommended rules for CDS model files in your project:

      cds add lint
      

      This automatically adds the settings for the ESlint VS Code extension to .vscode/settings.json, installs CDS ESLint plugin, and adds it to your ESLint configuration file.

    CDS Lint Rules

    The CDS Lint rules are a set of generic rules based on CAP best practices. The subset of these we consider most essential is part of the recommended configuration of the @sap/eslint-plugin-cds package.

    Model Validation
    RuleCategoryRecommendedFixableVersion
    assoc2many-ambiguous-keyModel Validation✔️1.0.1
    require-2many-oncondModel Validation✔️2.1.0
    sql-cast-suggestionModel Validation✔️1.0.8
    start-elements-lowercaseModel Validation🔧1.0.4
    start-entities-uppercaseModel Validation🔧1.0.4
    latest-cds-versionEnvironment1.0.4
    min-node-versionEnvironment✔️1.0.0
    no-db-keywords✔️2.1.0


    Customization

    Configuring CDS Lint Rules

    Individual package rules can also be configured to be turned off or have a different severity. For example, if you want to turn off the recommended environment rule min-node-version , just add the following lines to your ESLint configuration file, shown here for type json:

    {
        "rules": {
            "@sap/cds/min-node-version": 0
        }
    }
    

    Using the ESLint CLI

    If you want to have more control over the linting process, you can access the CDS ESLint plugin natively via the ESLint CLI. To determine the proper command line options, it can help to refer to the cds lint --debug output, which shows all of the options and flags available.

    For example:

    Linting:
    node ".../eslint.js" --debug --config ".../.eslintrc.js" ...

    Jupyter Notebooks

    You have the option to add a CAP Jupyter Notebook to your project.

    A CAP Jupyter Notebook is a Jupyter Notebook that serves you as a guide on how to create, navigate, and monitor CAP projects. With this approach, we want to encourage the CAP community to work with CAP in the same explorative manner that scientists work with their data, namely by:

    • Visually interacting with their code
    • Playing with REPL-type inputs (notebook input cells)
    • Storing persistent code (notebook output cells)

    The cell inputs/outputs are especially useful at later points in time when the project’s details have long been forgotten. In addition, notebooks are a good way to share, compare, and also reproduce projects.

    Get Started with cds init/add

    Initiate a new project, for example Bookshop, with the --add notebook option:

    cds init Bookshop --add notebook
    

    Use cds add to add it to an already existing project by navigating to that directory and running:

    cds add notebook
    

    This scrapes the content from the documentation Getting started in a nutshell and converts it to a Jupyter Notebook. This conversion makes the code cells interactive such that you can execute them on your local machine.

    Notebooks in Visual Studio Code

    In Visual Studio Code, you can open, execute, and interact with the CAP Jupyter Notebook as shown below:

    Opening and interacting with a CAP Jupyter Notebook in Visual Studio Code

    SAP Business Application Studio

    For the trial accounts, SAP Business Application Studio is only available on Amazon Web Services (AWS) - Frankfurt and US East (VA) regions.

    Learn more about using SAP Business Application Studio with a Trial account.

    For productive accounts SAP Business Application Studio is available in AWS and Azure regions.

    Learn more about using SAP Business Application Studio with a productive account.

    Log on to SAP BTP Cockpit

    1. Open the SAP BTP cockpit.

      If you are not subscribed to SAP Business Application Studio service, follow the onboarding tutorial.

    2. Choose SAP Business Application Studio from the Quick Tool Access section on the welcome page to SAP BTP Trial to access the service.

    Set Up Your Dev Space

    1. Choose Create Dev Space.

    2. Provide a name for your dev space.

    3. Choose Full Stack Cloud Application as the application type.

      By selecting Full Stack Cloud Application, your dev space comes with several extensions out of the box that you need to develop CAP applications. For example, CAP Tools, Java Tools, and MTA Tools are built in. This saves setup time. See Developer Guide for SAP Business Application Studio for more details.

    4. Choose Create Dev Space.

      The creation of the dev space takes a while. You see that the status for your dev space changes from STARTING to RUNNING. See Dev Space Types for more details.

    5. Once the dev space is running, choose the dev space by clicking on the dev space name.

      You’re using a trial version. Any dev space that hasn’t been running for 30 days will be deleted. See the full list of restrictions.

    Features

    To learn about the features specific to CAP development in the studio, see the guide Developing a CAP Application in SAP Business Application Studio

    Tutorials Using SAP Business Application Studio

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