# 🐧 Defining the Runtime Image with `ccpimage`

The `ccpimage` input defines the **Docker image** used to run the method.

This is required for all methods and determines the environment where your scripts or code will be executed.

You can choose:

- A minimal image like `bash`
- A language runtime (`python:3.9`, `r-base`)
- A custom image with preinstalled dependencies

---

## 🔧 Using a Simple Bash Image

To define methods that only require basic Unix commands (e.g., `wget`, `curl`, file manipulations),  
you can use `bash` as the default value in the `ccpimage` field.

![ccpimage bash](/_static/imgs/input_ccpimage_bash.png)

```json
"inputs": {
  "ccpimage": {
    "id": "ccpimage",
    "title": "Runtime",
    "description": "`bash`, a basic Unix Docker image.",
    "minOccurs": 1,
    "maxOccurs": 1,
    "schema": {
      "type": "string",
      "format": "url",
      "contentMediaType": "text/plain",
      "default": "bash",
      "readOnly": true
    }
  }
}
```

---

## ⚙️ Example: Parametric Shell Script

Let’s define a method that posts an input file to a REST API using `wget`.

```json
"inputs": {
  "url": {
    "title": "API URL",
    "schema": {
      "type": "string",
      "format": "url",
      "default": "https://api.example.org/annotate"
    }
  },
  "file": {
    "title": "Input file",
    "schema": {
      "type": "string",
      "format": "file"
    }
  }
}
```

![Input file example](/_static/imgs/input_file.png)

---

## 🚀 Execution Scripts

Your method logic is defined entirely via deploy and execute scripts:

```json
"additionalParameters": {
  "parameters": [
    {
      "name": "deploy-script",
      "value": [
        "echo {{file}} | base64 -d > /ccp_data/input"
      ]
    },
    {
      "name": "execute-script",
      "value": [
        "wget {{url}} --post-file /ccp_data/input -O /ccp_data/annotated.json"
      ]
    }
  ]
}
```

---

## 📄 Example Method

See the complete [Bash Example](/_static/methods_examples/Bash%20Example-1.0.0.json)

---

## 🔗 Related Pages

- 👨‍💻 [Building simple methods](/01_quickstart/05_building_simple_method)

- 🛠 [Script syntax and placeholders](./06_scripts_and_placeholders)
  
- 🔣 [Method descriptor structure](./07_method_json)

- 🧾 [Handling input field](./05_input_types/01_input_basic)