feat(Node Elasticsearch): update authentication to support API Key and Basic Auth

[everettbu]

Mirror of n8n-io/n8n#21405
Original author: justincastilla

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Summary

Adds API Key authentication support to the Elasticsearch node, enabling modern authentication for Elastic Cloud, Elastic Serverless, as well as self-hosted Elastic instances.

• Added "API Key" authentication type (now the default for new credentials)
• Maintained "Basic Auth" for backwards compatibility with existing workflows
• Updated credential test endpoint from /_xpack to / for Serverless compatibility
• Fixed baseURL template string handling to properly remove trailing slashes
• Enhanced authenticate() method to preserve existing request headers
• Added unit tests covering both authentication methods

Testing

• Created 5 unit tests for credential authentication
  • API Key authentication header generation
  • Basic Auth credential handling
  • Preservation of existing request headers
  • Both authentication methods validated independently

Updated UI

API Key Authentication Option:

Review / Merge checklist

• PR title and summary are descriptive. (conventions)
• Docs updated: PR Created: Docs: update Elasticsearch credentials documentation n8n-io/n8n-docs#3851
• Tests included.
• PR Labeled with release/backport (if the PR is an urgent fix that needs to be backported)

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Note

Adds API Key authentication (default) alongside Basic Auth, updates credential test and baseURL handling, and introduces unit tests for auth flows.

• Credentials (credentials/ElasticsearchApi.credentials.ts):
  • Add authType with options apiKey (default) and basicAuth; introduce apiKey, username, password; keep required baseUrl.
  • Implement authenticate(...) to apply Basic Auth or Authorization: ApiKey ...; preserves existing headers; legacy fallback when authType missing; input validation with clear errors.
  • Update test request to GET / and normalize baseURL by trimming trailing slashes.
• Types (nodes/Elastic/Elasticsearch/types.ts):
  • Extend ElasticsearchApiCredentials to include authType, apiKey, and optional username/password.
• Tests (nodes/Elastic/Elasticsearch/tests/credentials/ElasticsearchApi.test.ts):
  • Add unit tests for API Key and Basic Auth, header preservation, backward compatibility, and validation errors.

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