VARIABLES.md

# Variables in OpenServerless Task

This document lists general guidelines to define OpenServerless Tasks variable via the `ops` cli.

## General info:

OpenServerless Tasks variable are typically set issuing a command like `ops config VARIABLE=<value>`. These variable are stored under the `~/.ops/config.json` file. Variables name are splitted over the `_` character and the resulting parts are used to compose a json nested object having all the parts, that is given a variable with value `OPERATOR_COMPONENT_MINIO=true` the resulting json persisted into the configuration file will be something like

```json
{
    "operator":{
        "component":{
            "minio":true
        }
    }
}
```

## General guidelines:

With the above described behavior we have defined some general rules to be adopted when developing/updating OpenServerless Tasks variables

- Avoid to define variable starting with `OPS_` prefix. This prefix is reserved to the `ops` general config itself, and normally defined inside the `opsroot.json`. It is better to clearly distinguish task variable from the `ops` generated/reserved ones.
- Considering the `_` splitting rules, prefer variable names composed by a maximum of 4 parts to avoid too much nested `json` structure. This is to simplify readability of the `config.json` if manually inspected.
- Do not override variable used for configuration, with values obtained after the configuration has been applied (to create/update an Apache OpenServerless instance). This is to guarantee that we can always reconstruct the original `config.json` file. For instance OPS tasks defines an `OPERATOR_CONFIG_APIHOST` that should not be overridden. It is better to define a  `OUTPUT_APIHOST` instead.
- Specify volume size parameters with numerical value expressed as GB
- Specify memory size parameters with numerical value expressed as GB

## Variable prefixes category

This is a comprehensive list of variable prefix used in Ops tasks describing their purpose

| Variable Prefix | Purpose |
|---|---|
| OPERATOR_COMPONENT_  | Used to defined which OpenServerless Components needs to be deployed by the Operator   |
| OPERATOR_CONFIG_  | Global Ops Operator configuration parameters   |
| OPENWHISK_CONTROLLER_  | OpenWhisk Controller Configuration |
| OPENWHISK_INVOKER_  | OpenWhisk Invoker Configuration |
| OPENWHISK_  | OpenWhisk General configuration for limits, triggers etc etc |
| STORAGE_SIZE_  | Used to define various component allocated volumes size |
| SECRET_  | Used to define autogenerated secret |
| OUTPUT_  | Used to define calculated configuration parameters that are result of applying ops tasks against a running OpenServerless instance, if applies (APIHOST is one of them) |