feat: add UUID generation for events to ensure idempotency

[rafaeelaudibert]

This will help us improve our score on the SDK compliance harness

[github-actions]

posthog-elixir Compliance Report

Date: 2026-02-05 04:09:59 UTC
Duration: 105842ms

⚠️ Some Tests Failed

17/29 tests passed, 12 failed

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Capture Tests

⚠️ 17/29 tests passed, 12 failed

View Details

Test	Status	Duration
Format Validation.Event Has Required Fields	✅	609ms
Format Validation.Event Has Uuid	✅	609ms
Format Validation.Event Has Lib Properties	✅	610ms
Format Validation.Distinct Id Is String	✅	610ms
Format Validation.Token Is Present	✅	609ms
Format Validation.Custom Properties Preserved	✅	608ms
Format Validation.Event Has Timestamp	✅	609ms
Retry Behavior.Retries On 503	❌	5613ms
Retry Behavior.Does Not Retry On 400	✅	2611ms
Retry Behavior.Does Not Retry On 401	✅	2612ms
Retry Behavior.Respects Retry After Header	❌	5616ms
Retry Behavior.Implements Backoff	❌	15616ms
Retry Behavior.Retries On 500	❌	5614ms
Retry Behavior.Retries On 502	❌	5615ms
Retry Behavior.Retries On 504	❌	5614ms
Retry Behavior.Max Retries Respected	❌	15613ms
Deduplication.Generates Unique Uuids	✅	619ms
Deduplication.Preserves Uuid On Retry	❌	5614ms
Deduplication.Preserves Uuid And Timestamp On Retry	❌	10620ms
Deduplication.Preserves Uuid And Timestamp On Batch Retry	❌	5617ms
Deduplication.No Duplicate Events In Batch	✅	615ms
Deduplication.Different Events Have Different Uuids	✅	612ms
Compression.Sends Gzip When Enabled	❌	609ms
Batch Format.Uses Proper Batch Structure	✅	609ms
Batch Format.Flush With No Events Sends Nothing	✅	606ms
Batch Format.Multiple Events Batched Together	✅	614ms
Error Handling.Does Not Retry On 403	✅	2611ms
Error Handling.Does Not Retry On 413	✅	2613ms
Error Handling.Retries On 408	❌	5615ms

Failures

retry_behavior.retries_on_503

Expected at least 3 requests, got 1

retry_behavior.respects_retry_after_header

Expected at least 2 requests, got 1

retry_behavior.implements_backoff

Expected at least 3 requests, got 1

retry_behavior.retries_on_500

Expected at least 2 requests, got 1

retry_behavior.retries_on_502

Expected at least 2 requests, got 1

retry_behavior.retries_on_504

Expected at least 2 requests, got 1

retry_behavior.max_retries_respected

Expected 4 requests, got 1

deduplication.preserves_uuid_on_retry

Need at least 2 requests to check retry

deduplication.preserves_uuid_and_timestamp_on_retry

Expected at least 3 requests, got 1

deduplication.preserves_uuid_and_timestamp_on_batch_retry

Expected at least 2 requests, got 1

compression.sends_gzip_when_enabled

Header 'Content-Encoding' with value 'gzip' not found in requests

error_handling.retries_on_408

Expected at least 2 requests, got 1