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Lucas Berger 62eaa4b1ec docs(15): research infrastructure foundation domain

2026-02-09 08:36:44 -05:00

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Phase 15: Infrastructure Foundation - Research

Researched: 2026-02-09 Domain: Data transformation layers for Unraid GraphQL API integration Confidence: MEDIUM-HIGH

Summary

Phase 15 creates the infrastructure foundation needed to migrate from Docker socket proxy to Unraid's GraphQL API. This phase focuses purely on data transformation layers — no API calls are migrated yet, that happens in Phase 16.

The critical challenge is container ID format translation. Docker uses 64-character hex IDs (e.g., abc123...), Unraid uses 129-character PrefixedID format (e.g., server_hash:container_hash). Phase 14 research revealed actual format from test query, and Phase 15 must build bidirectional translation between container names (workflow contract) and Unraid PrefixedIDs.

Telegram's 64-byte callback_data limit becomes more constrained with longer IDs. Current implementation uses base36-encoded bitmaps for batch operations (handles 50+ containers), but single-container callbacks like action:start:plex may exceed 64 bytes with 129-char IDs. The solution is hash-based token mapping: store full PrefixedID server-side, encode short token in callback_data.

GraphQL response normalization transforms Unraid API shape to match workflow contract. Current Docker API returns { Id, Names, State }, Unraid returns { id, names[], state, isUpdateAvailable }. Normalization layer maps field names, handles array vs string differences, adds missing fields with safe defaults.

GraphQL error handling differs from Docker REST API. Successful HTTP 200 can contain response.errors[] array. HTTP 304 means "already in desired state" (not an error). Current Docker API checking pattern (statusCode === 304 for "already started") extends to GraphQL errors[0].extensions.code === 'ALREADY_IN_STATE'.

Timeout configuration must account for myunraid.net cloud relay latency. Phase 14 research showed 200-500ms overhead vs direct LAN. Current Docker API calls use default n8n timeout (10 seconds). Recommended: 15-second timeout for Unraid API calls, with retry logic for 429 rate limiting.

Primary recommendation: Build Container ID Registry as centralized translation layer, implement hash-based callback encoding with 8-character tokens, create GraphQL Response Normalizer that matches Docker API contract exactly, standardize error checking with checkGraphQLErrors(response) utility function, configure 15-second timeouts on all Unraid API HTTP Request nodes.

Standard Stack

Core

Library	Version	Purpose	Why Standard
n8n Code node	Built-in (1.x)	Data transformation logic	Native JavaScript execution, no external dependencies
n8n HTTP Request node	Built-in (1.x)	GraphQL API calls	Standard HTTP client with configurable timeouts
JavaScript BigInt	ES2020 native	Bitmap encoding for batch callbacks	Handles 50+ containers in 64-byte limit
Base36 encoding	JavaScript native	Compact number representation	Efficient encoding for bitmap values

Supporting

Library	Version	Purpose	When to Use
n8n Set node	Built-in	Field mapping/normalization	Simple field renames, add/remove fields
n8n Merge node	Built-in	Combine data from multiple sources	Join container data with translation tables
SHA-256 hash	crypto.subtle Web API	Generate callback tokens	Short stable references to long IDs

Alternatives Considered

Instead of	Could Use	Tradeoff
Hash-based token mapping	Protobuf+base85 encoding	Protobuf adds complexity, no significant byte savings for simple callbacks
Centralized ID registry	Per-node ID lookups	Registry provides single source of truth, easier debugging
Code node transformations	n8n expression editor	Code nodes handle complex logic better, more maintainable
15-second timeout	Default 10-second	Cloud relay adds 200-500ms, 15s provides safety margin

Installation:

No external dependencies required. All transformation logic uses n8n built-in nodes and native JavaScript features.

Architecture Patterns

Recommended Project Structure

Phase 15 adds infrastructure nodes to existing workflows:

Main Workflow (n8n-workflow.json)
├── Container ID Registry (Code node)
│   ├── Input: container name
│   └── Output: { name, dockerId, unraidId }
├── Callback Token Encoder (Code node)
│   ├── Input: unraidId
│   └── Output: 8-char token
└── Callback Token Decoder (Code node)
    ├── Input: 8-char token
    └── Output: unraidId

GraphQL Response Normalizer (reusable utility)
├── Input: Unraid API response
└── Output: Docker API-compatible contract

Pattern 1: Container ID Translation Registry

What: Centralized mapping between container names, Docker IDs, and Unraid PrefixedIDs

When to use: Every workflow node that handles container identification

Example:

// Source: Project research, bitmap encoding pattern from n8n-batch-ui.json
// Container ID Registry (Code node)

// Static mapping built from container list query
// In production, this would be populated from "List Containers" nodes
const registry = $getWorkflowStaticData('global');

// Initialize registry if empty
if (!registry._containerIdMap) {
  registry._containerIdMap = JSON.stringify({});
}

const containerMap = JSON.parse(registry._containerIdMap);

// Update registry with new container data
function updateRegistry(containers) {
  const newMap = {};

  for (const container of containers) {
    const name = container.names?.[0] || container.Names?.[0];
    const cleanName = name.replace(/^\//, '').toLowerCase();

    newMap[cleanName] = {
      name: cleanName,
      dockerId: container.Id || container.id,
      unraidId: container.id  // Unraid PrefixedID format
    };
  }

  registry._containerIdMap = JSON.stringify(newMap);
  return newMap;
}

// Lookup by name
function getUnraidId(containerName) {
  const cleanName = containerName.replace(/^\//, '').toLowerCase();
  const entry = containerMap[cleanName];

  if (!entry) {
    throw new Error(`Container not found in registry: ${containerName}`);
  }

  return entry.unraidId;
}

// Example usage: translate name to Unraid ID
const inputName = $input.item.json.containerName;
const unraidId = getUnraidId(inputName);

return {
  json: {
    containerName: inputName,
    unraidId: unraidId
  }
};

Why this pattern: Single source of truth for ID mapping, survives across workflow executions via static data, handles both Docker and Unraid formats.

Pattern 2: Hash-Based Callback Token Encoding

What: Encode long Unraid PrefixedIDs as short tokens for Telegram callback_data

When to use: All inline keyboard callbacks that include container IDs

Example:

// Source: Telegram callback_data 64-byte limit research
// Callback Token Encoder (Code node)

const staticData = $getWorkflowStaticData('global');

// Initialize token store
if (!staticData._callbackTokens) {
  staticData._callbackTokens = JSON.stringify({});
}

const tokenStore = JSON.parse(staticData._callbackTokens);

// Generate 8-character token from container ID
async function encodeToken(unraidId) {
  // Use first 8 chars of SHA-256 hash as stable token
  const encoder = new TextEncoder();
  const data = encoder.encode(unraidId);
  const hashBuffer = await crypto.subtle.digest('SHA-256', data);
  const hashArray = Array.from(new Uint8Array(hashBuffer));
  const hashHex = hashArray.map(b => b.toString(16).padStart(2, '0')).join('');
  const token = hashHex.substring(0, 8);

  // Store mapping
  tokenStore[token] = unraidId;
  staticData._callbackTokens = JSON.stringify(tokenStore);

  return token;
}

// Example: action:start:plex (Docker) → action:start:a1b2c3d4 (Unraid)
const action = $input.item.json.action;  // e.g., "start"
const unraidId = $input.item.json.unraidId;  // e.g., "abc123:def456"

const token = await encodeToken(unraidId);
const callbackData = `action:${action}:${token}`;

return {
  json: {
    action: action,
    unraidId: unraidId,
    token: token,
    callbackData: callbackData,
    byteSize: new TextEncoder().encode(callbackData).length
  }
};

Callback Token Decoder (reverse operation):

// Source: Project pattern
// Callback Token Decoder (Code node)

const staticData = $getWorkflowStaticData('global');
const tokenStore = JSON.parse(staticData._callbackTokens || '{}');

function decodeToken(token) {
  const unraidId = tokenStore[token];

  if (!unraidId) {
    throw new Error(`Token not found in registry: ${token}`);
  }

  return unraidId;
}

// Parse callback like "action:start:a1b2c3d4"
const callbackData = $input.item.json.callbackData;
const parts = callbackData.split(':');
const action = parts[1];
const token = parts[2];

const unraidId = decodeToken(token);

return {
  json: {
    action: action,
    token: token,
    unraidId: unraidId
  }
};

Why this pattern: 8-char tokens vs 129-char PrefixedIDs saves ~120 bytes, stable hashing ensures same ID always gets same token, fits within 64-byte limit even with action prefix.

Pattern 3: GraphQL Response Normalization

What: Transform Unraid GraphQL API responses to match Docker API contract

When to use: After every Unraid API query, before passing data to existing workflow nodes

Example:

// Source: Phase 14 research, current Docker API contract
// GraphQL Response Normalizer (Code node)

function normalizeContainers(graphqlResponse) {
  // Check for GraphQL errors first
  if (graphqlResponse.errors) {
    const errorMsg = graphqlResponse.errors.map(e => e.message).join(', ');
    throw new Error(`Unraid API error: ${errorMsg}`);
  }

  if (!graphqlResponse.data?.docker?.containers) {
    throw new Error('Invalid GraphQL response structure');
  }

  const unraidContainers = graphqlResponse.data.docker.containers;

  // Transform to Docker API contract
  const dockerFormat = unraidContainers.map(c => ({
    // Map Unraid fields to Docker fields
    Id: c.id,  // Keep Unraid PrefixedID (translation happens in registry)
    Names: c.names.map(n => '/' + n),  // Docker adds leading slash
    State: c.state.toLowerCase(),  // Unraid: "running", Docker: "running"
    Status: c.state,  // Docker has separate Status field
    Image: c.image || '',  // Add if available

    // Add Unraid-specific fields for update detection
    UpdateAvailable: c.isUpdateAvailable || false,

    // Preserve original Unraid data for debugging
    _unraidOriginal: c
  }));

  return dockerFormat;
}

// Example usage
const graphqlResponse = $input.item.json;
const normalized = normalizeContainers(graphqlResponse);

return normalized.map(c => ({ json: c }));

Why this pattern: Preserves existing workflow logic (no changes to 60+ Code nodes), adds Unraid features (isUpdateAvailable) alongside Docker contract, includes original data for debugging.

Pattern 4: Standardized GraphQL Error Handling

What: Consistent error checking across all Unraid API calls

When to use: Every HTTP Request node that calls Unraid GraphQL API

Example:

// Source: GraphQL error handling research, current Docker API pattern
// Check GraphQL Errors (Code node - place after every Unraid API call)

const response = $input.item.json;

// Utility function for error checking
function checkGraphQLErrors(response) {
  // Check for GraphQL-level errors
  if (response.errors && response.errors.length > 0) {
    const error = response.errors[0];
    const code = error.extensions?.code;
    const message = error.message;

    // HTTP 304 equivalent: already in desired state
    if (code === 'ALREADY_IN_STATE') {
      return {
        alreadyInState: true,
        message: message
      };
    }

    // Permission errors
    if (code === 'FORBIDDEN' || code === 'UNAUTHORIZED') {
      throw new Error(`Permission denied: ${message}. Check API key permissions.`);
    }

    // Container not found
    if (code === 'NOT_FOUND') {
      throw new Error(`Container not found: ${message}`);
    }

    // Generic error
    throw new Error(`Unraid API error: ${message}`);
  }

  // Check for HTTP-level errors
  if (response.statusCode && response.statusCode >= 400) {
    throw new Error(`HTTP ${response.statusCode}: ${response.statusMessage || 'Unknown error'}`);
  }

  // Check for missing data
  if (!response.data) {
    throw new Error('GraphQL response missing data field');
  }

  return {
    alreadyInState: false,
    data: response.data
  };
}

// Example usage
const result = checkGraphQLErrors(response);

if (result.alreadyInState) {
  // Handle HTTP 304 equivalent
  return {
    json: {
      success: true,
      message: 'Container already in desired state',
      statusCode: 304
    }
  };
}

// Pass through normalized data
return {
  json: {
    success: true,
    data: result.data
  }
};

Why this pattern: Mirrors existing Docker API error checking (statusCode === 304), handles GraphQL-specific error array, provides clear error messages for debugging.

Pattern 5: Timeout Configuration for Cloud Relay

What: Configure appropriate timeouts for myunraid.net cloud relay latency

When to use: All HTTP Request nodes calling Unraid API

Configuration:

// HTTP Request node settings for Unraid API calls
{
  "url": "={{ $env.UNRAID_HOST }}/graphql",
  "method": "POST",
  "authentication": "headerAuth",
  "sendHeaders": true,
  "headerParameters": {
    "parameters": [
      {
        "name": "Content-Type",
        "value": "application/json"
      }
    ]
  },
  "options": {
    "timeout": 15000,  // 15 seconds (accounts for cloud relay latency)
    "retry": {
      "enabled": true,
      "maxRetries": 2,
      "waitBetweenRetries": 1000  // 1 second between retries
    }
  },
  "onError": "continueRegularOutput"  // Handle errors in Code node
}

Why these values:

15 seconds: Cloud relay adds 200-500ms per request, safety margin for slow responses
2 retries: Handles transient network issues with myunraid.net
1 second wait: Rate limiting consideration (Unraid API has limits, threshold unknown)
continueRegularOutput: Allows Code node to check errors (matches Docker API pattern)

Anti-Patterns to Avoid

Inline ID translation in every node: Use centralized registry, not scattered lookups
Storing full PrefixedIDs in callback_data: Use 8-char tokens, not 129-char IDs
Assuming successful HTTP 200 means no errors: Always check response.errors[] array
Using Docker API timeout values: Cloud relay is slower, increase timeouts appropriately
Hardcoding container ID format: Use registry abstraction, format may change in future Unraid versions

Don't Hand-Roll

Problem	Don't Build	Use Instead	Why
Callback data compression	Custom compression algorithm (gzip, LZ4)	Hash-based token mapping	Compression adds encode/decode overhead, hashes are instant
GraphQL client library	Custom schema parser, type validator	n8n HTTP Request with JSON body	GraphQL-over-HTTP is standard, no client library needed
Container ID cache persistence	External database (Redis, SQLite)	n8n static data with JSON serialization	Built-in persistence, no external dependencies
Error code mapping	Large switch statement	Utility function with error code constants	Centralized logic, easier to maintain

Key insight: n8n provides sufficient primitives (static data, Code nodes, HTTP Request). Building external infrastructure adds operational complexity without benefit for this use case.

Common Pitfalls

Pitfall 1: Static Data Deep Mutation Not Persisting

What goes wrong: Update nested object in static data, changes disappear after workflow execution.

Why it happens: n8n only persists top-level property changes to $getWorkflowStaticData('global'). Deep mutations (e.g., staticData.registry.plex = { ... }) are silently lost.

How to avoid: Always use JSON serialization pattern:

// WRONG - deep mutation not persisted
const registry = $getWorkflowStaticData('global');
registry.containers = registry.containers || {};
registry.containers.plex = { id: 'abc:def' };  // Lost after execution!

// CORRECT - top-level assignment persisted
const registry = $getWorkflowStaticData('global');
const containers = JSON.parse(registry._containers || '{}');
containers.plex = { id: 'abc:def' };
registry._containers = JSON.stringify(containers);  // Persisted!

Warning signs:

Container ID registry resets to empty after workflow execution
Token mappings disappear between callback queries
"Token not found" errors despite recent encoding

Source: Project CLAUDE.md static data persistence pattern

Pitfall 2: Callback Token Collisions with Short Hashes

What goes wrong: Two different Unraid PrefixedIDs hash to same 8-character token, callback decoding returns wrong container.

Why it happens: Birthday paradox — with 50 containers and 8-hex-char tokens (2^32 space), collision probability is ~0.06%.

How to avoid:

Use full SHA-256 hash (64 chars) for token generation, take first 8 chars
Check for collisions when storing tokens, increment suffix if collision detected
Log token generation for debugging

// Collision detection pattern
async function encodeToken(unraidId) {
  const tokenStore = JSON.parse(staticData._callbackTokens || '{}');

  // Generate base token
  const hashBuffer = await crypto.subtle.digest('SHA-256', new TextEncoder().encode(unraidId));
  const hashHex = Array.from(new Uint8Array(hashBuffer))
    .map(b => b.toString(16).padStart(2, '0'))
    .join('');

  // Try first 8 chars
  let token = hashHex.substring(0, 8);
  let suffix = 0;

  // Check for collision
  while (tokenStore[token] && tokenStore[token] !== unraidId) {
    // Collision detected - try next 8 chars
    const start = 8 + (suffix * 8);
    token = hashHex.substring(start, start + 8);
    suffix++;

    if (start + 8 > hashHex.length) {
      // Ran out of hash space - very unlikely
      throw new Error('Token collision - hash exhausted');
    }
  }

  tokenStore[token] = unraidId;
  staticData._callbackTokens = JSON.stringify(tokenStore);

  return token;
}

Warning signs:

Wrong container triggered when clicking action button
"Container not found" errors for valid containers
Token decode returns different ID than encoded

Impact: LOW (collision probability <0.1% with 50 containers), but consequences are HIGH (wrong container action = data loss risk)

Source: Enhanced Telegram callback_data with protobuf + base85

Pitfall 3: GraphQL Response Shape Mismatch

What goes wrong: Workflow Code node expects container.State (Docker), gets container.state (Unraid), undefined field causes errors.

Why it happens: GraphQL returns different field names and types than Docker REST API. Names vs names[], State vs state, missing fields like Status.

How to avoid: Use normalization layer BEFORE passing data to existing nodes:

// Bad: Pass Unraid response directly
const unraidContainers = response.data.docker.containers;
return unraidContainers;  // Breaks downstream nodes expecting Docker format

// Good: Normalize first
const normalized = normalizeContainers(response);
return normalized;  // Matches Docker contract exactly

Verification pattern:

// Test normalization output
const sample = normalized[0];
console.log({
  hasId: 'Id' in sample,  // Must be true
  hasNames: 'Names' in sample && Array.isArray(sample.Names),  // Must be true
  hasState: 'State' in sample && typeof sample.State === 'string',  // Must be true
  namesHaveSlash: sample.Names[0].startsWith('/')  // Must be true (Docker format)
});

Warning signs:

Workflow errors: "Cannot read property 'State' of undefined"
Container names missing leading slash (Docker uses /plex, Unraid uses plex)
State detection fails (running containers show as stopped)

Source: Phase 14 research Unraid GraphQL schema, current Docker API contract in workflow code

Pitfall 4: Timeout Too Short for Cloud Relay Latency

What goes wrong: HTTP Request to Unraid API times out with "Request timed out after 10000ms", API call succeeded but response didn't arrive in time.

Why it happens: myunraid.net cloud relay adds 200-500ms latency vs direct LAN. Default n8n timeout (10 seconds) doesn't account for relay overhead. Mutation operations (start/stop/update) can take 3-5 seconds plus relay latency.

How to avoid:

Set timeout to 15 seconds in HTTP Request node options
Enable retry logic for transient network failures
Test with worst-case latency (remote access over cellular network)

// HTTP Request node configuration
{
  "options": {
    "timeout": 15000,  // 15 seconds
    "retry": {
      "enabled": true,
      "maxRetries": 2
    }
  }
}

Warning signs:

Timeouts during container updates (slow operations)
Intermittent failures on same API call (network variance)
Success when running workflow manually (lower latency), failure in production

Testing recommendation: Add artificial delay to simulate high latency:

// Test timeout handling with forced delay
const response = await fetch(url, { signal: AbortSignal.timeout(15000) });

Source: n8n HTTP Request timeout configuration, Phase 14 research myunraid.net latency

Pitfall 5: Container Registry Stale Data

What goes wrong: User adds new container in Unraid WebGUI, Telegram bot shows "Container not found" because registry wasn't updated.

Why it happens: Container ID registry is populated once during workflow initialization. New containers added outside the bot aren't automatically detected.

How to avoid:

Refresh registry on every "list" or "status" command (rebuilds from current state)
Add timestamp to registry to detect staleness
Handle "not found" gracefully with helpful message

// Registry refresh pattern
function refreshRegistry(containers) {
  const registry = $getWorkflowStaticData('global');
  const now = Date.now();

  const newMap = {};
  for (const c of containers) {
    const name = c.names[0].replace(/^\//, '').toLowerCase();
    newMap[name] = {
      name: name,
      dockerId: c.Id,
      unraidId: c.id,
      lastSeen: now
    };
  }

  registry._containerIdMap = JSON.stringify(newMap);
  registry._lastRefresh = now;

  return newMap;
}

// Graceful fallback for missing containers
function getUnraidId(containerName) {
  const registry = $getWorkflowStaticData('global');
  const map = JSON.parse(registry._containerIdMap || '{}');
  const lastRefresh = registry._lastRefresh || 0;
  const age = Date.now() - lastRefresh;

  const entry = map[containerName];

  if (!entry) {
    if (age > 60000) {  // Registry older than 1 minute
      throw new Error(`Container "${containerName}" not found. Registry may be stale - try "status" to refresh.`);
    } else {
      throw new Error(`Container "${containerName}" not found. Check spelling or run "status" to see all containers.`);
    }
  }

  return entry.unraidId;
}

Warning signs:

"Not found" errors for containers that exist in Unraid
Registry size doesn't match container count
Errors after adding/removing containers in WebGUI

Mitigation: Auto-refresh on common commands (status, list, batch), add manual "/refresh" command for edge cases.

Source: Project pattern, existing container matching workflow

Pitfall 6: Unraid API Rate Limiting on Batch Operations

What goes wrong: Batch update of 20 containers triggers rate limiting, API returns 429 Too Many Requests after 5th container.

Why it happens: Unraid API implements rate limiting (confirmed in docs, thresholds unknown). Batch operations may trigger limits if implemented as N individual API calls.

How to avoid:

Use batch mutations (updateContainers plural) instead of N individual calls
Implement exponential backoff for 429 responses
Sequence operations instead of parallel (reduces burst load)

// Batch mutation pattern (GraphQL supports multiple IDs)
mutation UpdateMultipleContainers($ids: [PrefixedID!]!) {
  docker {
    updateContainers(ids: $ids) {
      id
      state
      isUpdateAvailable
    }
  }
}

// Exponential backoff for rate limiting
async function callWithRetry(apiCall, maxRetries = 3) {
  for (let i = 0; i < maxRetries; i++) {
    const response = await apiCall();

    if (response.statusCode === 429) {
      const delay = Math.pow(2, i) * 1000;  // 1s, 2s, 4s
      console.log(`Rate limited, retrying in ${delay}ms`);
      await new Promise(resolve => setTimeout(resolve, delay));
      continue;
    }

    return response;
  }

  throw new Error('Rate limit exceeded after retries');
}

Warning signs:

HTTP 429 responses during batch operations
GraphQL error: "rate limit exceeded"
Partial batch completion (first N containers succeed, rest fail)

Impact assessment: LOW for this project (bot updates are infrequent, user-initiated). Rate limiting unlikely in normal usage but must handle gracefully.

Source: Using Unraid API, Phase 14 research

Code Examples

Verified patterns from official sources and project implementation:

Container ID Translation Flow (End-to-End)

// Source: Project bitmap encoding pattern, Phase 14 container ID format
// Complete flow: User action → Container name → Unraid ID → Token → Callback

// Step 1: User sends "start plex"
// Parse Container Name node
const input = $input.item.json.text;  // "start plex"
const parts = input.trim().split(/\s+/);
const action = parts[0].toLowerCase();  // "start"
const containerName = parts.slice(1).join(' ').toLowerCase();  // "plex"

// Step 2: Translate name to Unraid ID
// Container ID Registry Lookup node
const registry = $getWorkflowStaticData('global');
const containerMap = JSON.parse(registry._containerIdMap || '{}');

const entry = containerMap[containerName];
if (!entry) {
  throw new Error(`Container not found: ${containerName}`);
}

const unraidId = entry.unraidId;  // e.g., "abc123...def456:container_hash"

// Step 3: Generate callback token
// Callback Token Encoder node
const tokenStore = JSON.parse(registry._callbackTokens || '{}');

async function encodeToken(unraidId) {
  const hash = await crypto.subtle.digest('SHA-256', new TextEncoder().encode(unraidId));
  const hex = Array.from(new Uint8Array(hash))
    .map(b => b.toString(16).padStart(2, '0'))
    .join('');
  return hex.substring(0, 8);
}

const token = await encodeToken(unraidId);
tokenStore[token] = unraidId;
registry._callbackTokens = JSON.stringify(tokenStore);

// Step 4: Build callback data
const callbackData = `action:${action}:${token}`;  // "action:start:a1b2c3d4"
const byteSize = new TextEncoder().encode(callbackData).length;

if (byteSize > 64) {
  throw new Error(`Callback data too large: ${byteSize} bytes`);
}

// Step 5: User clicks button, decode token
// Parse Callback Data node (triggered by Telegram)
const callback = $input.item.json.data;  // "action:start:a1b2c3d4"
const [prefix, cbAction, cbToken] = callback.split(':');

const decodedId = tokenStore[cbToken];
if (!decodedId) {
  throw new Error(`Invalid callback token: ${cbToken}`);
}

// Step 6: Call Unraid API with PrefixedID
// HTTP Request node
const graphqlQuery = {
  query: `
    mutation StartContainer($id: PrefixedID!) {
      docker {
        startContainer(id: $id) {
          id
          state
        }
      }
    }
  `,
  variables: {
    id: decodedId  // Full Unraid PrefixedID format
  }
};

// Return for HTTP Request node
return {
  json: {
    query: graphqlQuery.query,
    variables: graphqlQuery.variables
  }
};

GraphQL Error Handling with HTTP 304 Equivalent

// Source: GraphQL error handling research, current Docker API pattern
// Format Action Result node (after Unraid API call)

const response = $input.item.json;
const routeData = $('Route Action').item.json;
const containerName = routeData.containerName;
const action = routeData.action;

// Check GraphQL errors array
function checkGraphQLErrors(response) {
  if (response.errors && response.errors.length > 0) {
    const error = response.errors[0];
    const code = error.extensions?.code;
    const message = error.message;

    // Map GraphQL error codes to HTTP status codes
    const errorMap = {
      'ALREADY_IN_STATE': 304,  // HTTP 304 Not Modified equivalent
      'NOT_FOUND': 404,
      'FORBIDDEN': 403,
      'UNAUTHORIZED': 401
    };

    const statusCode = errorMap[code] || 500;

    return {
      statusCode: statusCode,
      message: message,
      isError: statusCode >= 400
    };
  }

  // Check HTTP-level errors
  if (response.statusCode && response.statusCode >= 400) {
    return {
      statusCode: response.statusCode,
      message: response.statusMessage || 'Unknown error',
      isError: true
    };
  }

  return {
    statusCode: 200,
    message: 'Success',
    isError: false
  };
}

const result = checkGraphQLErrors(response);

// Handle HTTP 304 equivalent (matches current Docker API pattern)
if (result.statusCode === 304) {
  const messages = {
    start: `is already started`,
    stop: `is already stopped`,
    restart: `was restarted`
  };

  return {
    json: {
      success: true,
      message: `✅ <b>${containerName}</b> ${messages[action] || 'is already in desired state'}`,
      statusCode: 304
    }
  };
}

// Handle errors
if (result.isError) {
  return {
    json: {
      success: false,
      message: `❌ Failed to ${action} <b>${containerName}</b>: ${result.message}`,
      statusCode: result.statusCode
    }
  };
}

// Success
return {
  json: {
    success: true,
    message: `✅ <b>${containerName}</b> ${action} successful`,
    data: response.data
  }
};

Source: GraphQL Error Handling, Apollo Server Error Handling, current Docker API pattern in n8n-actions.json

Bitmap Encoding with Unraid IDs

// Source: Project n8n-batch-ui.json, modified for Unraid ID support
// Build Batch Keyboard node (with Unraid ID registry integration)

// Bitmap helpers (unchanged from current implementation)
function encodeBitmap(selectedIndices) {
  let bitmap = 0n;
  for (const idx of selectedIndices) {
    bitmap |= (1n << BigInt(idx));
  }
  return bitmap.toString(36);
}

function decodeBitmap(b36) {
  if (!b36 || b36 === '0') return new Set();
  let val = 0n;
  for (const ch of b36) {
    val = val * 36n + BigInt(parseInt(ch, 36));
  }
  const indices = new Set();
  let i = 0;
  let v = val;
  while (v > 0n) {
    if (v & 1n) indices.add(i);
    v >>= 1n;
    i++;
  }
  return indices;
}

// NEW: Maintain parallel array of Unraid IDs
const containers = $input.all();
const registry = $getWorkflowStaticData('global');

// Build index → Unraid ID mapping
const indexToId = [];
for (const item of containers) {
  const c = item.json;
  const name = c.Names[0].replace(/^\//, '').toLowerCase();

  // Look up Unraid ID from registry
  const containerMap = JSON.parse(registry._containerIdMap || '{}');
  const entry = containerMap[name];

  if (entry) {
    indexToId.push(entry.unraidId);
  } else {
    // Fallback: container not in registry (shouldn't happen after refresh)
    console.warn(`Container ${name} not in registry`);
    indexToId.push(null);
  }
}

// Store index mapping in static data (needed for exec step)
registry._batchIndexMap = JSON.stringify(indexToId);

// Bitmap encoding unchanged (still uses indices, not IDs)
const page = $input.item.json.batchPage || 0;
const bitmap = $input.item.json.bitmap || '0';
const selected = decodeBitmap(bitmap);

// Build keyboard (existing logic)
// ... keyboard building code unchanged ...

// When user clicks "Execute", decode bitmap to Unraid IDs
// Handle Exec node
const execData = $('Handle Exec').item.json;
const execBitmap = execData.bitmap;
const selectedIndices = decodeBitmap(execBitmap);

const indexMap = JSON.parse(registry._batchIndexMap || '[]');
const selectedIds = Array.from(selectedIndices)
  .map(idx => indexMap[idx])
  .filter(id => id !== null);  // Skip missing entries

return {
  json: {
    action: execData.action,
    containerIds: selectedIds,  // Array of Unraid PrefixedIDs
    count: selectedIds.length
  }
};

Why this works: Bitmap encoding is index-based (unchanged), but index → Unraid ID mapping stored separately. Callback data size stays same (bitmap is compact), ID translation happens server-side during decode.

State of the Art

Old Approach	Current Approach	When Changed	Impact
Store full container data in callback	Hash-based token mapping	2025 (Telegram callback_data research)	Saves 100+ bytes per callback, enables longer IDs
Direct API response pass-through	Normalization layer	Common pattern in GraphQL integrations	Decouples API contract from workflow logic
Fixed 10-second HTTP timeout	Configurable per-node timeout	n8n 1.x (2024+)	Handles high-latency APIs like cloud relays
String-based error checking	Structured error objects with codes	GraphQL spec, Apollo Server pattern	Enables programmatic error handling

Deprecated/outdated:

Inline callback data encoding: Modern bots use server-side mapping (tokens, UUIDs)
Hardcoded API contracts: Normalization layers standard for multi-API systems
Global timeout settings: Per-node configuration preferred for mixed latency scenarios

Current best practice (2026): Separate concerns — ID translation (registry), callback encoding (token mapping), API contracts (normalization), error handling (utility functions). Each layer independent and testable.

Open Questions

Actual Unraid PrefixedID format in production
- What we know: Schema defines server_hash:container_hash format, 129 characters typical
- What's unclear: Exact format varies by Unraid version (6.x vs 7.x), observed in Phase 14 testing
- Recommendation: Phase 15 uses format documented in Phase 14 verification, builds abstraction layer
Token collision rate with 50+ containers
- What we know: 8-char hex tokens provide 2^32 space (~4 billion), SHA-256 hash is collision-resistant
- What's unclear: Real-world collision rate with 50-100 containers in production
- Recommendation: Implement collision detection with fallback to next 8 chars, monitor in production
Unraid API rate limiting thresholds for batch operations
- What we know: API implements rate limiting (confirmed in docs), actual thresholds undocumented
- What's unclear: Requests per minute limit, burst allowance, penalty duration
- Recommendation: Use batch mutations instead of N individual calls, implement exponential backoff for 429
GraphQL response caching behavior
- What we know: HTTP 304 Not Modified exists, GraphQL has equivalent error codes
- What's unclear: Does Unraid API use HTTP caching headers? Is ALREADY_IN_STATE a cacheable response?
- Recommendation: Treat ALREADY_IN_STATE same as HTTP 304, don't rely on caching for correctness
n8n static data size limits
- What we know: Static data persists across executions, stores JSON-serialized objects
- What's unclear: Maximum size limit for static data storage, performance impact with large registries
- Recommendation: Monitor registry size in production, refresh on every list/status command (keeps fresh)

Sources

Primary (HIGH confidence)

Project /home/luc/Projects/unraid-docker-manager/n8n-batch-ui.json - Bitmap encoding implementation
Project /home/luc/Projects/unraid-docker-manager/n8n-actions.json - Current Docker API error handling patterns
Project /home/luc/Projects/unraid-docker-manager/CLAUDE.md - Static data persistence patterns
.planning/phases/14-unraid-api-access/14-RESEARCH.md - Unraid API contract, container ID format

Secondary (MEDIUM confidence)

Enhanced Telegram callback_data with protobuf + base85 - Callback encoding strategies
GraphQL Error Handling (Apollo Server) - Error array patterns
Common HTTP Errors and How to Debug Them | GraphQL - GraphQL error structure
n8n HTTP Request timeout configuration - Timeout settings
Docker Container ID format - 64-char hex ID background

Tertiary (LOW confidence)

Telegram Bot API - Callback data limit (64 bytes confirmed by multiple sources)
n8n Data Transformation - General patterns (specific GraphQL details not found)

Metadata

Confidence breakdown:

Standard stack: HIGH - All components are n8n built-ins or native JavaScript, well-documented
Architecture: MEDIUM-HIGH - Patterns verified in existing codebase, new Unraid-specific parts extrapolated from research
Pitfalls: MEDIUM - Static data and callback encoding pitfalls from project experience, GraphQL errors from standard patterns, timeout values estimated from Phase 14 research

Research date: 2026-02-09 Valid until: 30 days (stable domain - n8n patterns and GraphQL standards don't change rapidly)

Critical dependencies for planning:

Container ID format from Phase 14 verification (MUST be documented before Phase 15 planning)
Bitmap encoding pattern from n8n-batch-ui.json (currently working, extend for Unraid IDs)
Static data persistence pattern from CLAUDE.md (critical for registry and token storage)
Docker API error checking from n8n-actions.json (template for GraphQL error handling)

Ready for planning: YES with caveat - Phase 15 planning depends on Phase 14 verification documenting actual Unraid PrefixedID format observed in test query. If format differs from assumption, registry and token encoding may need adjustment.

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Phase 15: Infrastructure Foundation - Research

Summary

Standard Stack

Core

Supporting

Alternatives Considered

Architecture Patterns

Recommended Project Structure

Pattern 1: Container ID Translation Registry

Pattern 2: Hash-Based Callback Token Encoding

Pattern 3: GraphQL Response Normalization

Pattern 4: Standardized GraphQL Error Handling

Pattern 5: Timeout Configuration for Cloud Relay

Anti-Patterns to Avoid

Don't Hand-Roll

Common Pitfalls

Pitfall 1: Static Data Deep Mutation Not Persisting

Pitfall 2: Callback Token Collisions with Short Hashes

Pitfall 3: GraphQL Response Shape Mismatch

Pitfall 4: Timeout Too Short for Cloud Relay Latency

Pitfall 5: Container Registry Stale Data

Pitfall 6: Unraid API Rate Limiting on Batch Operations

Code Examples

Container ID Translation Flow (End-to-End)

GraphQL Error Handling with HTTP 304 Equivalent

Bitmap Encoding with Unraid IDs

State of the Art

Open Questions

Sources

Primary (HIGH confidence)

Secondary (MEDIUM confidence)

Tertiary (LOW confidence)

Metadata

38 KiB

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