# Task status and results

What the task states mean, polling or callbacks, downloading results and cancelling tasks.

After you create a task, read its progress and result by task ID, or wait for a callback.

## Task status

`queued` (Queued) → `processing` (Processing) → `succeeded` (Succeeded); the other final states `failed` (Failed) and `cancelled` (Cancelled) are free.

While a task is `processing`, `phase` names the current stage: preparing inputs, waiting, starting, generating, confirming the result, finishing and awaiting settlement. Every value is on [Statuses and reasons](./api-docs-en-api-statuses.md#task-phase).

## Three status fields

| Field | Meaning |
| --- | --- |
| `status` | Task execution; the final states are `succeeded`, `failed` and `cancelled`. |
| `delivery_status` | Delivery of the result files; download them once it is `available`. |
| `settlement_status` | Billing settlement; the charge is final once it is `settled`. |

## Poll

Read the task every few seconds until `status` is final:

```bash
curl --request GET "${CHENVOYA_BASE_URL}/v1/video/tasks/${TASK_ID}" \
  --header "Authorization: Bearer ${CHENVOYA_API_KEY}"
```

```python
import urllib.request
import urllib.parse
import json
import os
import sys
import re
import uuid

key = os.environ["CHENVOYA_API_KEY"].strip()
if not key or re.search(r"[\x00-\x1f\x7f-\x9f]", key):
    sys.exit("Set CHENVOYA_API_KEY to a non-empty value without control characters")
base = os.environ["CHENVOYA_BASE_URL"].rstrip("/")
headers = {"Authorization": "Bearer " + key}
TASK_ID = os.environ["TASK_ID"]
path = "/v1/video/tasks/{task_id}".replace("{task_id}", urllib.parse.quote(TASK_ID, safe=""))
request = urllib.request.Request(base + path, data=None, headers=headers, method="GET")
try:
    with urllib.request.urlopen(request) as response:
        print(response.read().decode("utf-8"))
except urllib.request.HTTPError as error:
    print(error.read().decode("utf-8"))
    sys.exit(1)
```

```javascript
// Needs Node.js 20 or later; save it as a .mjs file and run it.
const key = process.env.CHENVOYA_API_KEY?.trim();
if (!key || /[\x00-\x1f\x7f-\x9f]/.test(key)) {
  console.error("Set CHENVOYA_API_KEY to a non-empty value without control characters");
  process.exit(1);
}
const base = process.env.CHENVOYA_BASE_URL;
if (!base) throw new Error("Set CHENVOYA_BASE_URL");
const headers = {Authorization: `Bearer ${key}`};
const TASK_ID = process.env.TASK_ID;
if (!TASK_ID) throw new Error("Set TASK_ID");
const path = "/v1/video/tasks/{task_id}".replace("{task_id}", encodeURIComponent(TASK_ID));
const response = await fetch(base.replace(/\/$/, "") + path, {method: "GET", headers, body: undefined});
console.log(await response.text());
if (!response.ok) process.exitCode = 1;
```

```go
package main

import (
	"fmt"
	"io"
	"net/http"
	"net/url"
	"os"
	"regexp"
	"strings"
)

func main() {
	key := strings.TrimSpace(os.Getenv("CHENVOYA_API_KEY"))
	if key == "" || regexp.MustCompile(`[\x00-\x1f\x7f-\x9f]`).MatchString(key) {
		fail("Set CHENVOYA_API_KEY to a non-empty value without control characters")
	}
	base := strings.TrimRight(os.Getenv("CHENVOYA_BASE_URL"), "/")
	if base == "" {
		fail("Set CHENVOYA_BASE_URL")
	}
	taskID := os.Getenv("TASK_ID")
	if taskID == "" {
		fail("Set TASK_ID")
	}
	path := strings.Replace("/v1/video/tasks/{task_id}", "{task_id}", url.PathEscape(taskID), 1)
	request, err := http.NewRequest("GET", base+path, nil)
	if err != nil {
		fail(err.Error())
	}
	request.Header.Set("Authorization", "Bearer "+key)
	response, err := http.DefaultClient.Do(request)
	if err != nil {
		fail(err.Error())
	}
	text, err := io.ReadAll(response.Body)
	response.Body.Close()
	if err != nil {
		fail(err.Error())
	}
	fmt.Println(string(text))
	if response.StatusCode < 200 || response.StatusCode > 299 {
		os.Exit(1)
	}
}

func fail(message string) {
	fmt.Fprintln(os.Stderr, message)
	os.Exit(1)
}
```

## Callbacks

After you register and verify a callback address in the console, pass `callback_url` when you create a task and you receive `task.completed` when it finishes. The event has no download link: read the task once more. See [Receive callbacks](./api-docs-en-callbacks.md).

## Download the result

A succeeded task lists its result files in `output.assets` with `role` `result`. `url` is an HTTPS download link; each task read signs a fresh one that works for up to 24 hours and never after `expires_at` (7 days after the result is ready by default); when it has expired or is not available, `url` is null and `download_status` says why. Save the file to your own storage in time.

```bash
curl --output video.mp4 "$VIDEO_URL"
```

## List tasks

`GET /v1/video/tasks` lists all of your team's tasks, whichever API key created them, newest first. A list entry holds the IDs, model, statuses and times; read usage, charges, results and errors from the task by its ID.

```bash
curl --request GET "${CHENVOYA_BASE_URL}/v1/video/tasks" \
  --header "Authorization: Bearer ${CHENVOYA_API_KEY}"
```

```python
import urllib.request
import urllib.parse
import json
import os
import sys
import re
import uuid

key = os.environ["CHENVOYA_API_KEY"].strip()
if not key or re.search(r"[\x00-\x1f\x7f-\x9f]", key):
    sys.exit("Set CHENVOYA_API_KEY to a non-empty value without control characters")
base = os.environ["CHENVOYA_BASE_URL"].rstrip("/")
headers = {"Authorization": "Bearer " + key}
path = "/v1/video/tasks"
request = urllib.request.Request(base + path, data=None, headers=headers, method="GET")
try:
    with urllib.request.urlopen(request) as response:
        print(response.read().decode("utf-8"))
except urllib.request.HTTPError as error:
    print(error.read().decode("utf-8"))
    sys.exit(1)
```

```javascript
// Needs Node.js 20 or later; save it as a .mjs file and run it.
const key = process.env.CHENVOYA_API_KEY?.trim();
if (!key || /[\x00-\x1f\x7f-\x9f]/.test(key)) {
  console.error("Set CHENVOYA_API_KEY to a non-empty value without control characters");
  process.exit(1);
}
const base = process.env.CHENVOYA_BASE_URL;
if (!base) throw new Error("Set CHENVOYA_BASE_URL");
const headers = {Authorization: `Bearer ${key}`};
const path = "/v1/video/tasks";
const response = await fetch(base.replace(/\/$/, "") + path, {method: "GET", headers, body: undefined});
console.log(await response.text());
if (!response.ok) process.exitCode = 1;
```

```go
package main

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

func main() {
	key := strings.TrimSpace(os.Getenv("CHENVOYA_API_KEY"))
	if key == "" || regexp.MustCompile(`[\x00-\x1f\x7f-\x9f]`).MatchString(key) {
		fail("Set CHENVOYA_API_KEY to a non-empty value without control characters")
	}
	base := strings.TrimRight(os.Getenv("CHENVOYA_BASE_URL"), "/")
	if base == "" {
		fail("Set CHENVOYA_BASE_URL")
	}
	path := "/v1/video/tasks"
	request, err := http.NewRequest("GET", base+path, nil)
	if err != nil {
		fail(err.Error())
	}
	request.Header.Set("Authorization", "Bearer "+key)
	response, err := http.DefaultClient.Do(request)
	if err != nil {
		fail(err.Error())
	}
	text, err := io.ReadAll(response.Body)
	response.Body.Close()
	if err != nil {
		fail(err.Error())
	}
	fmt.Println(string(text))
	if response.StatusCode < 200 || response.StatusCode > 299 {
		os.Exit(1)
	}
}

func fail(message string) {
	fmt.Fprintln(os.Stderr, message)
	os.Exit(1)
}
```

## Cancel a task

`POST /v1/video/tasks/{task_id}/cancel` needs an `Idempotency-Key` and no body.

- Before generation starts, cancellation takes effect at once: the answer is `effective`, the task becomes `cancelled` and the whole reservation is released.
- After generation starts, the answer is `not_effective` with reason `generation_already_started`; the task continues and is settled as usual.
- A finished task without a cancellation returns `409 task_not_cancellable`.

```bash
IDEMPOTENCY_KEY=${IDEMPOTENCY_KEY:-$(uuidgen)}
printf '%s\n' "Save IDEMPOTENCY_KEY for retries: ${IDEMPOTENCY_KEY}" >&2
curl --request POST "${CHENVOYA_BASE_URL}/v1/video/tasks/${TASK_ID}/cancel" \
  --header "Authorization: Bearer ${CHENVOYA_API_KEY}" \
  --header "Idempotency-Key: ${IDEMPOTENCY_KEY}"
```

```python
import urllib.request
import urllib.parse
import json
import os
import sys
import re
import uuid

key = os.environ["CHENVOYA_API_KEY"].strip()
if not key or re.search(r"[\x00-\x1f\x7f-\x9f]", key):
    sys.exit("Set CHENVOYA_API_KEY to a non-empty value without control characters")
base = os.environ["CHENVOYA_BASE_URL"].rstrip("/")
headers = {"Authorization": "Bearer " + key}
idempotency = os.environ.get("IDEMPOTENCY_KEY") or str(uuid.uuid4())
print("Save IDEMPOTENCY_KEY for retries: " + idempotency, file=sys.stderr)
headers["Idempotency-Key"] = idempotency
TASK_ID = os.environ["TASK_ID"]
path = "/v1/video/tasks/{task_id}/cancel".replace("{task_id}", urllib.parse.quote(TASK_ID, safe=""))
request = urllib.request.Request(base + path, data=None, headers=headers, method="POST")
try:
    with urllib.request.urlopen(request) as response:
        print(response.read().decode("utf-8"))
except urllib.request.HTTPError as error:
    print(error.read().decode("utf-8"))
    sys.exit(1)
```

```javascript
// Needs Node.js 20 or later; save it as a .mjs file and run it.
const key = process.env.CHENVOYA_API_KEY?.trim();
if (!key || /[\x00-\x1f\x7f-\x9f]/.test(key)) {
  console.error("Set CHENVOYA_API_KEY to a non-empty value without control characters");
  process.exit(1);
}
const base = process.env.CHENVOYA_BASE_URL;
if (!base) throw new Error("Set CHENVOYA_BASE_URL");
const headers = {Authorization: `Bearer ${key}`};
const idempotency = process.env.IDEMPOTENCY_KEY || crypto.randomUUID();
console.error("Save IDEMPOTENCY_KEY for retries: " + idempotency);
headers["Idempotency-Key"] = idempotency;
const TASK_ID = process.env.TASK_ID;
if (!TASK_ID) throw new Error("Set TASK_ID");
const path = "/v1/video/tasks/{task_id}/cancel".replace("{task_id}", encodeURIComponent(TASK_ID));
const response = await fetch(base.replace(/\/$/, "") + path, {method: "POST", headers, body: undefined});
console.log(await response.text());
if (!response.ok) process.exitCode = 1;
```

```go
package main

import (
	"crypto/rand"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"os"
	"regexp"
	"strings"
)

func main() {
	key := strings.TrimSpace(os.Getenv("CHENVOYA_API_KEY"))
	if key == "" || regexp.MustCompile(`[\x00-\x1f\x7f-\x9f]`).MatchString(key) {
		fail("Set CHENVOYA_API_KEY to a non-empty value without control characters")
	}
	base := strings.TrimRight(os.Getenv("CHENVOYA_BASE_URL"), "/")
	if base == "" {
		fail("Set CHENVOYA_BASE_URL")
	}
	taskID := os.Getenv("TASK_ID")
	if taskID == "" {
		fail("Set TASK_ID")
	}
	path := strings.Replace("/v1/video/tasks/{task_id}/cancel", "{task_id}", url.PathEscape(taskID), 1)
	request, err := http.NewRequest("POST", base+path, nil)
	if err != nil {
		fail(err.Error())
	}
	request.Header.Set("Authorization", "Bearer "+key)
	idempotency := os.Getenv("IDEMPOTENCY_KEY")
	if idempotency == "" {
		idempotency = newOperationKey()
	}
	fmt.Fprintln(os.Stderr, "Save IDEMPOTENCY_KEY for retries: "+idempotency)
	request.Header.Set("Idempotency-Key", idempotency)
	response, err := http.DefaultClient.Do(request)
	if err != nil {
		fail(err.Error())
	}
	text, err := io.ReadAll(response.Body)
	response.Body.Close()
	if err != nil {
		fail(err.Error())
	}
	fmt.Println(string(text))
	if response.StatusCode < 200 || response.StatusCode > 299 {
		os.Exit(1)
	}
}

func fail(message string) {
	fmt.Fprintln(os.Stderr, message)
	os.Exit(1)
}

// newOperationKey returns a random UUID; save it to retry with the same value.
func newOperationKey() string {
	var b [16]byte
	if _, err := rand.Read(b[:]); err != nil {
		fail(err.Error())
	}
	b[6] = b[6]&0x0f | 0x40
	b[8] = b[8]&0x3f | 0x80
	return fmt.Sprintf("%x-%x-%x-%x-%x", b[0:4], b[4:6], b[6:8], b[8:10], b[10:16])
}
```

## Failure reasons

A failed task gives its reason in `error.code`, such as `input_fetch_failed` when an input could not be downloaded or `generation_failed`. Every value is on [Statuses and reasons](./api-docs-en-api-statuses.md#task-error). Failed and cancelled tasks are settled at no charge.

## Next steps

- [Receive callbacks](./api-docs-en-callbacks.md): After you register a callback address, we send it signed events when a task finishes and when its charge is settled.
- [How billing works](./api-docs-en-billing.md): Funds for the upper bound are reserved at creation and settled on actual usage; failed and cancelled tasks are free.
- [Read a video task](./api-docs-en-api-video-tasks-retrieve.md): Check execution progress, delivery, usage and the billing summary.