writing-a-cell-bal-project.md

Developing & running a cell with resources and/or tests

In this section let's focus on initialize, build, run and push operations for pet-be cell. Pet-be cell requires a swagger file when building the image. Therefore, this has to be written as a Ballerina project. Follow the instructions listed below to create the cell.

1. Execute cellery init --project command from the command prompt, and provide the project name as pet-be.

   $ cellery init --project
   ? Project name:  [my-project] pet-be
   Created new Ballerina project at pet-be
   
   Next:
       Move into the project directory and use `ballerina add <module-name>` to
       add a new Ballerina module.
   Added new ballerina module at 'src/pet_be'
   
   
   ✔ Initialized Ballerina project: pet-be
   
   What's next?
   --------------------------------------------------------
   Execute the following command to build the image:
     $ cellery build pet-be organization/image_name:version
   --------------------------------------------------------
   
   

The above step will auto generate a Ballerina project with the name pet-be in the present working directory. The structure of the Ballerina project generated is shown below.

pet-be/
├── Ballerina.toml
└── src
    └── pet_be
        ├── pet_be.bal
        ├── resources
        └── tests
            ├── pet_be_test.bal
            └── resources

All files related to the cell are created within the pet_be Ballerina module. Tests has to be written for the Ballerina module pet_be. The cell file is identical to the file that was created when developing & running your first cell.

2. Modify the files to add components and tests required for the pet-be cell. The final project after modifications can be found in the pet-be sample.

3. Build the Cellery image for pet-be project by executing the cellery build command as shown below. For building the cell you should give the path to the pet-be Ballerina project as the argument to the CLI command. Note CELLERY_HUB_ORG is your organization name in Cellery hub.

   $ cellery build hello-world-cell.bal <CELLERY_HUB_ORG>/hello-world-cell:1.0.0
   ✔ Creating temporary executable main bal file
   Compiling source
       celleryio/pet_be:0.6.0
   
   Creating balos
       target/balo/pet_be-2019r3-any-0.1.0.balo
   
   Generating executables
       target/bin/pet_be.jar
   
   Running executables
   
   ✔ Executing ballerina build
   ✔ Generating metadata
   ✔ Creating the image zip file
   
   
   ✔ Successfully built image: <CELLERY_HUB_ORG>/pet-be-cell:1.0.0
   
   What's next?
   --------------------------------------------------------
   Execute the following command to run the image:
     $ cellery run <CELLERY_HUB_ORG>/pet-be-cell:1.0.0
   --------------------------------------------------------
   

4. Execute cellery run, cellery list instances, cellery view, cellery push and cellery terminate commands as you already did when developing & running your first cell.

What's Next?

• Cell Specification - Key concepts of Cellery.
• How to code cells? - explains how Cellery cells are written.
• CLI commands - reference for CLI commands.
• Cell API versioning - api versioning for cells.
• Samples - a collection of useful samples.