function = client.functions.create(
    name="myfunction",
    folder="path/to/code",
    function_path="path/to/function.py")

function = client.functions.create(
    name="myfunction", file_id=123, function_path="path/to/function.py")

function = client.functions.create(name="myfunction", function_handle=handle)

def handle(client, data):
    """
    [requirements]
    numpy
    [/requirements]
    """
    pass
function = client.functions.create(name="myfunction", function_handle=handle)

curl --request POST \
  --url https://{cluster}.cognitedata.com/api/v1/projects/{project}/functions \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "items": [
    {
      "name": "My awesome function",
      "fileId": 5467347282343
    }
  ]
}
'

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({items: [{name: 'My awesome function', fileId: 5467347282343}]})
};

fetch('https://{cluster}.cognitedata.com/api/v1/projects/{project}/functions', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://{cluster}.cognitedata.com/api/v1/projects/{project}/functions",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'items' => [
        [
                'name' => 'My awesome function',
                'fileId' => 5467347282343
        ]
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://{cluster}.cognitedata.com/api/v1/projects/{project}/functions"

	payload := strings.NewReader("{\n  \"items\": [\n    {\n      \"name\": \"My awesome function\",\n      \"fileId\": 5467347282343\n    }\n  ]\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://{cluster}.cognitedata.com/api/v1/projects/{project}/functions")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"items\": [\n    {\n      \"name\": \"My awesome function\",\n      \"fileId\": 5467347282343\n    }\n  ]\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://{cluster}.cognitedata.com/api/v1/projects/{project}/functions")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"items\": [\n    {\n      \"name\": \"My awesome function\",\n      \"fileId\": 5467347282343\n    }\n  ]\n}"

response = http.request(request)
puts response.read_body

{
  "items": [
    {
      "id": 4503599627370496,
      "createdTime": 123455234,
      "status": "Queued",
      "name": "myfunction",
      "fileId": 4503599627370496,
      "functionType": "classic",
      "externalId": "my.known.id",
      "owner": "user@cognite.com",
      "description": "My fantastic function with advanced ML",
      "metadata": {},
      "secrets": {
        "MySecret": "***"
      },
      "functionPath": "myfunction/handler.py",
      "envVars": {
        "MyKey": "MyValue"
      },
      "cpu": 1,
      "memory": 1.5,
      "runtime": "py313",
      "runtimeVersion": "Python 3.11.10",
      "error": {
        "message": "Function deployment failed.",
        "trace": "ERROR: Could not find a version that satisfies the requirement pandas==99.0.0\nERROR: No matching distribution found for pandas==99.0.0"
      },
      "lastCalled": 1730204346000
    }
  ]
}

{
  "error": {
    "code": 401,
    "message": "Could not authenticate.",
    "missing": [
      {}
    ],
    "duplicated": [
      {}
    ]
  }
}