Functions

Functions are HTTP-triggered ephemeral containers — lightweight serverless workloads managed by Norn.

Overview

Unlike webservers (always running) or cron jobs (scheduled), functions run on demand. Each invocation:

1. Starts a container from the deployed image
2. Passes the request via environment variables
3. Captures stdout as the response
4. Records the execution in the database

infraspec

app: thumbnail-gen
role: function
build:
  dockerfile: Dockerfile
function:
  timeout: 30       # max seconds (default: 30)
  trigger: http     # trigger type (default: http)
  memory: 256m      # container memory limit (default: 256m)

Fields

Field	Type	Default	Description
function.timeout	int	30	Maximum execution time in seconds
function.trigger	string	"http"	Trigger type (currently only http)
function.memory	string	"256m"	Container memory limit

Protocol

The function container receives the request as environment variables:

Variable	Description
NORN_REQUEST_BODY	The request body (JSON string)
NORN_REQUEST_METHOD	HTTP method (POST)
NORN_REQUEST_PATH	Request path

Plus any static env variables from the infraspec.

The container's stdout is captured as the response. Exit code 0 = success.

Example function

Go

package main

import (
    "encoding/json"
    "fmt"
    "os"
)

func main() {
    body := os.Getenv("NORN_REQUEST_BODY")

    var req struct {
        URL string `json:"url"`
    }
    json.Unmarshal([]byte(body), &req)

    // Process the request...
    result := map[string]string{
        "status": "processed",
        "input":  req.URL,
    }

    out, _ := json.Marshal(result)
    fmt.Println(string(out))
}

Node.js

const body = JSON.parse(process.env.NORN_REQUEST_BODY || '{}')

// Process the request...
const result = {
  status: 'processed',
  input: body.url
}

console.log(JSON.stringify(result))

Invoking

UI

1. Click the Invoke button on the function's app card
2. Enter a request body in the panel
3. Click Invoke to run
4. View the result in the execution history

CLI

# Simple invocation
norn invoke my-func --body '{"key": "value"}'

# From a file
norn invoke my-func --body @request.json

# Empty body
norn invoke my-func

API

curl -X POST http://localhost:8800/api/apps/my-func/invoke \
  -H 'Content-Type: application/json' \
  -d '{"key": "value"}'

Execution history

View past invocations:

• UI: Click History on the function's app card
• API: GET /api/apps/{id}/function/history

Each execution record includes:

• Status (running, succeeded, failed, timed_out)
• Exit code
• Container output
• Duration in milliseconds
• Timestamps

Lifecycle