# Examples
8 example modules demonstrating apcore-cli usage.
## Quick Start
```bash
# From the project root
make build
export PATH=.bin:$PATH
export APCORE_EXTENSIONS_ROOT=examples/extensions
# Run a module
apcore-cli math.add --a 5 --b 10
# {"sum": 15}
# List all modules
apcore-cli list
# Run all examples at once
bash examples/run_examples.sh
```
## Available Modules
| `math.add` | Add two integers | `apcore-cli math.add --a 5 --b 10` |
| `math.multiply` | Multiply two integers | `apcore-cli math.multiply --a 6 --b 7` |
| `text.upper` | Uppercase a string | `apcore-cli text.upper --text hello` |
| `text.reverse` | Reverse a string | `apcore-cli text.reverse --text abcdef` |
| `text.wordcount` | Count words/chars/lines | `apcore-cli text.wordcount --text "hello world"` |
| `sysutil.info` | System information | `apcore-cli sysutil.info` |
| `sysutil.env` | Read an env variable | `apcore-cli sysutil.env --name HOME` |
| `sysutil.disk` | Disk usage stats | `apcore-cli sysutil.disk --path /` |
## Writing Your Own Module
Each module is a directory with two files:
```
extensions/
└── greet/
└── hello/
├── module.json <- descriptor (schema + metadata)
└── run.sh <- execution logic (any language)
```
### Step 1: Create `module.json`
Defines the module's ID, description, input/output schemas, and executable:
```json
{
"name": "greet.hello",
"description": "Greet someone by name",
"tags": ["demo"],
"executable": "run.sh",
"input_schema": {
"type": "object",
"properties": {
"name": { "type": "string", "description": "Person to greet" },
"greeting": { "type": "string", "description": "Greeting word", "default": "Hello" }
},
"required": ["name"]
},
"output_schema": {
"type": "object",
"properties": {
"message": { "type": "string" }
}
}
}
```
### Step 2: Create `run.sh`
Reads JSON from stdin, writes JSON to stdout. Can be written in **any language**:
```bash
#!/usr/bin/env bash
python3 -c "
import json, sys
d = json.load(sys.stdin)
name = d['name']
greeting = d.get('greeting', 'Hello')
print(json.dumps({'message': f'{greeting}, {name}!'}))
"
```
Make it executable:
```bash
chmod +x run.sh
```
### Step 3: Run it
```bash
apcore-cli --extensions-dir ./extensions greet.hello --name World
# {"message": "Hello, World!"}
apcore-cli --extensions-dir ./extensions greet.hello --name Alice --greeting Hi
# {"message": "Hi, Alice!"}
# Auto-generated help from input_schema
apcore-cli --extensions-dir ./extensions greet.hello --help
```
### How It Works
```
apcore-cli greet.hello --name World
│
├── 1. Read module.json → register schema + flags
├── 2. Parse --name World → {"name": "World"}
├── 3. Validate input against input_schema
└── 4. Spawn run.sh, pipe JSON stdin → stdout
│
└── {"message": "Hello, World!"}
```
The CLI only cares about the JSON stdin/stdout protocol. Your `run.sh` can call Python, Node, Rust binaries, APIs, or anything else.
## STDIN Piping
```bash
# Pipe JSON input directly
# CLI flags override STDIN values
# Chain with other tools