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Understanding job status values and proper error handling is essential for building robust applications with the Queue API.

​
Job Status Values

Every job progresses through a series of states: 
type JobStatus = "pending" | "processing" | "completed" | "failed";

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Status Lifecycle

1

pending

Job is queued and waiting to start. This is the initial state after submission.
2

processing

Job is actively being processed by the backend. This is where the actual video generation happens.
3

completed

Job finished successfully. The result video is ready to download.
4

failed

Job failed during processing. Check the error message for details.

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Checking Job Status

Use client.queue.status() to check the current state of a job: 
import { createDecartClient } from "@decart/sdk";

const client = createDecartClient({
  apiKey: process.env.DECART_API_KEY,
});

const status = await client.queue.status("job_abc123");

console.log("Job ID:", status.job_id);
console.log("Status:", status.status);

​
Response Type

type JobStatusResponse = {
  job_id: string;   // Unique job identifier
  status: JobStatus;  // Current status
};

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Retrieving Results

Once a job reaches "completed" status, retrieve the result: 
const status = await client.queue.status(jobId);

if (status.status === "completed") {
  // Download the video
  const videoBlob = await client.queue.result(jobId);
  
  // Save to file (Node.js)
  const arrayBuffer = await videoBlob.arrayBuffer();
  await fs.writeFile("output.mp4", Buffer.from(arrayBuffer));
  
  // Or create object URL (browser)
  const url = URL.createObjectURL(videoBlob);
  videoElement.src = url;
}
Only call client.queue.result() when the job status is "completed". Calling it on incomplete jobs will result in an error.

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Error Handling

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Failed Jobs

When using submitAndPoll(), check the result status: 
const result = await client.queue.submitAndPoll({
  model: models.video("lucy-pro-t2v"),
  prompt: "A beautiful sunset",
});

if (result.status === "completed") {
  console.log("Success! Video size:", result.data.size, "bytes");
  // Process the video blob
  displayVideo(result.data);
} else if (result.status === "failed") {
  console.error("Job failed:", result.error);
  // Show error to user
  showError(`Video generation failed: ${result.error}`);
}

​
Manual Status Checks

When polling manually: 
const job = await client.queue.submit({
  model: models.video("lucy-pro-t2v"),
  prompt: "Mountain landscape",
});

let status = job.status;
while (status === "pending" || status === "processing") {
  await new Promise(resolve => setTimeout(resolve, 1500));
  const statusResponse = await client.queue.status(job.job_id);
  status = statusResponse.status;
}

if (status === "completed") {
  const video = await client.queue.result(job.job_id);
  console.log("Success!");
} else if (status === "failed") {
  console.error("Job failed");
  // Implement retry logic, notify user, etc.
}

​
Validation Errors

Input validation errors occur before job submission: 
try {
  const job = await client.queue.submit({
    model: models.video("lucy-pro-t2v"),
    prompt: "",  // Invalid: empty string
  });
} catch (error) {
  console.error("Validation error:", error.message);
  // Example output:
  // "Invalid inputs for lucy-pro-t2v: String must contain at least 1 character(s)"
}
Common validation errors:
  • Empty or too long prompts (max 1000 characters)
  • Invalid file inputs (wrong format, inaccessible URL)
  • Missing required parameters
  • Invalid parameter combinations (e.g., both prompt and reference_image for lucy-restyle-v2v)

​
Network Errors

Handle network and API errors: 
try {
  const result = await client.queue.submitAndPoll({
    model: models.video("lucy-pro-t2v"),
    prompt: "Beautiful landscape",
  });
  
  if (result.status === "completed") {
    handleSuccess(result.data);
  } else {
    handleJobFailure(result.error);
  }
} catch (error) {
  // Network error, auth error, or other exception
  console.error("Request failed:", error.message);
  
  if (error.message.includes("401")) {
    showError("Invalid API key");
  } else if (error.message.includes("network")) {
    showError("Network error - please check your connection");
  } else {
    showError("An unexpected error occurred");
  }
}

​
Comprehensive Error Handling Example

import { createDecartClient, models } from "@decart/sdk";

const client = createDecartClient({
  apiKey: process.env.DECART_API_KEY,
});

async function generateVideo(prompt: string) {
  try {
    console.log("Submitting job...");
    
    const result = await client.queue.submitAndPoll({
      model: models.video("lucy-pro-t2v"),
      prompt,
      onStatusChange: (job) => {
        console.log(`[${job.job_id}] Status: ${job.status}`);
        
        // Update UI based on status
        if (job.status === "pending") {
          showMessage("Job queued, waiting to start...");
        } else if (job.status === "processing") {
          showMessage("Generating video...");
        }
      },
    });
    
    // Check result
    if (result.status === "completed") {
      console.log("✓ Video generated successfully");
      console.log("  Size:", result.data.size, "bytes");
      console.log("  Type:", result.data.type);
      
      // Save or display the video
      const arrayBuffer = await result.data.arrayBuffer();
      await fs.writeFile("output.mp4", Buffer.from(arrayBuffer));
      
      return { success: true, video: result.data };
    } else {
      console.error("✗ Job failed:", result.error);
      console.error("  Job ID:", result.job_id);
      
      return { success: false, error: result.error };
    }
  } catch (error) {
    // Handle validation and network errors
    console.error("✗ Request failed:", error.message);
    
    if (error.message.includes("Invalid inputs")) {
      console.error("  Fix your input parameters");
    } else if (error.message === "Polling aborted") {
      console.error("  Request was cancelled");
    } else {
      console.error("  Check your network connection and API key");
    }
    
    return { success: false, error: error.message };
  }
}

// Usage
const result = await generateVideo("A serene mountain lake at dawn");

if (result.success) {
  console.log("Video is ready!");
} else {
  console.log("Failed to generate video:", result.error);
}

​
Timeout Behavior

The backend automatically fails jobs that take longer than 10 minutes. When a job times out, its status changes to "failed". You don’t need to implement your own timeout logic.
If you want to cancel polling before the backend timeout: 
const controller = new AbortController();

// Cancel after 5 minutes
setTimeout(() => controller.abort(), 5 * 60 * 1000);

try {
  const result = await client.queue.submitAndPoll({
    model: models.video("lucy-pro-t2v"),
    prompt: "Complex scene with many elements",
    signal: controller.signal,
  });
} catch (error) {
  if (error.message === "Polling aborted") {
    console.log("Cancelled polling after 5 minutes");
  }
}

​
Retry Strategies

Implement retry logic for failed jobs: 
async function generateVideoWithRetry(prompt: string, maxRetries = 3) {
  for (let attempt = 1; attempt <= maxRetries; attempt++) {
    console.log(`Attempt ${attempt}/${maxRetries}`);
    
    const result = await client.queue.submitAndPoll({
      model: models.video("lucy-pro-t2v"),
      prompt,
    });
    
    if (result.status === "completed") {
      return { success: true, data: result.data };
    }
    
    console.warn(`Attempt ${attempt} failed:`, result.error);
    
    // Wait before retrying (exponential backoff)
    if (attempt < maxRetries) {
      const delay = Math.pow(2, attempt) * 1000; // 2s, 4s, 8s
      console.log(`Waiting ${delay}ms before retry...`);
      await new Promise(resolve => setTimeout(resolve, delay));
    }
  }
  
  return { success: false, error: "Max retries exceeded" };
}

// Usage
const result = await generateVideoWithRetry("A magical forest scene");
if (result.success) {
  console.log("Success after retries!");
}

​
Next Steps

Overview

Review Queue API concepts and workflow

Submit Jobs

Learn how to submit jobs for different models

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