# 🐳 CCP Runtime Architecture

This page explains how the CCP platform executes methods inside **containerized runtimes** using a deploy/execute approach.

---

## 🧱 Base Architecture

Each method runs in an **isolated container** (e.g. Docker) provided by a runtime (`ccpimage`).

CCP mounts a temporary execution volume at:

```
/ccp_data/
```

This folder is used for:

- Storing downloaded input files
- Writing outputs and logs
- Temporary data exchange

---

## 📜 Deploy and Execute Scripts

Each execution involves **two sequential scripts**:

### 🛠 Deploy Script

Runs first.  
Used to prepare the environment:

- Clones code repositories
- Installs dependencies
- Downloads data
- Sets permissions

### 🚀 Execute Script

Runs after deploy.  
Used to run the actual algorithm:

- Executes your script or binary
- Uses data in `/ccp_data/`
- Writes outputs to `/ccp_data/`

Both scripts are defined in the method’s `method.json`.

---

## 🧪 Runtime Example

Given this configuration:

```json
"ccpimage": "python:3.9",
"deploy-script": [
  "git clone https://github.com/user/tool.git /src",
  "pip install -r /src/requirements.txt",
  "wget {{input_url}} -O /ccp_data/input.csv"
],
"execute-script": [
  "python3 /src/main.py --input /ccp_data/input.csv --output /ccp_data/result.json"
]
```

CCP will:

1. Start a `python:3.9` container
2. Run the deploy commands
3. Run the execution commands
4. Collect all `/ccp_data/*` files as output

---

## 🔐 Credentials Handling

Secret values (e.g., API keys) can be passed using secure inputs (`format: Secret`).  
You can use them via placeholders like `{{api_key}}` inside the scripts.

---

## 🌍 Supported Runtimes

CCP currently supports:

- Docker images (`bash`, `python`, `jupyter`, `gdal`, `r-base`, etc.)
- Custom base images via `ccpimage` parameter
- Experimental: pre-bundled consolidated runtimes

---

## 🔗 Related Pages

- 🧭 [Platform architecture](./01_platform_architecture.md)

- 🧱 [Deploy and execute scripts](/05_advanced_topics/02_execution_engine/04_runtimes.md)

- 📦 [Method structure](../03_methods/01_internal_representation.md)

- 🧩 [Intro to method development](../../04_methods_development/00_index.md)

---

## 🧩 Inputs and Placeholders

Inputs defined in the method form (e.g., text, file, URL) are passed to the scripts using **placeholders** like:

```bash
--input {{input_file}} --option {{threshold}}
```

At runtime, these placeholders are replaced with the actual values provided by the user.

Files from inputs (workspace, URLs, uploads) are automatically downloaded or decoded into `/ccp_data/`.

---

## 📑 Metadata and Provenance

During execution, CCP generates a set of **metadata files**:

- `metadata_request.json`: user inputs and configuration
- `metadata_jobStatus.json`: status and timestamps
- `metadata_provo.xml`: provenance metadata (agents, entities, activities)

These help track:

- Who ran what
- When and with which parameters
- How outputs were generated

You can inspect these files from the **execution results view** or download them for auditing and reproducibility.

---

## 🔗 Related Pages

- 🧭 [Platform architecture](./01_platform_architecture.md)

- 🧱 [Deploy and execute scripts](/05_advanced_topics/02_execution_engine/04_runtimes.md)

- 📦 [Method structure](/05_advanced_topics/03_methods/01_internal_representation.md)

- 🧩 [Intro to method development](/04_methods_development/00_index.md)