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Logs endpoints

Retrieve logs for your Langflow flow.

Enable log retrieval​

The /logs endpoint requires log retrieval to be enabled in your Langflow instance.

  1. To enable log retrieval, include these values in your .env file:


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    LANGFLOW_ENABLE_LOG_RETRIEVAL=True
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    LANGFLOW_LOG_RETRIEVER_BUFFER_SIZE=10000
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    LANGFLOW_LOG_LEVEL=DEBUG

    Log retrieval requires that LANGFLOW_LOG_RETRIEVER_BUFFER_SIZE is greater than 0. The default value is 10000.

  2. Start Langflow with the updated .env:


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    uv run langflow run --env-file .env

Stream logs​

Stream logs in real-time using Server Sent Events (SSE).


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curl -X GET \
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"$LANGFLOW_URL/logs-stream" \
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-H "accept: text/event-stream" \
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-H "x-api-key: $LANGFLOW_API_KEY"

Result

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keepalive
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{"1736355791151": "2025-01-08T12:03:11.151218-0500 DEBUG Building Chat Input\n"}
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{"1736355791485": "2025-01-08T12:03:11.485380-0500 DEBUG consumed event add_message-153bcd5d-ef4d-4ece-8cc0-47c6b6a9ef92 (time in queue, 0.0000, client 0.0001)\n"}
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{"1736355791499": "2025-01-08T12:03:11.499704-0500 DEBUG consumed event end_vertex-3d7125cd-7b8a-44eb-9113-ed5b785e3cf3 (time in queue, 0.0056, client 0.0047)\n"}
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{"1736355791502": "2025-01-08T12:03:11.502510-0500 DEBUG consumed event end-40d0b363-5618-4a23-bbae-487cd0b9594d (time in queue, 0.0001, client 0.0004)\n"}
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{"1736355791513": "2025-01-08T12:03:11.513097-0500 DEBUG Logged vertex build: 729ff2f8-6b01-48c8-9ad0-3743c2af9e8a\n"}
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{"1736355791834": "2025-01-08T12:03:11.834982-0500 DEBUG Telemetry data sent successfully.\n"}
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{"1736355791941": "2025-01-08T12:03:11.941840-0500 DEBUG Telemetry data sent successfully.\n"}
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keepalive

Retrieve logs with optional parameters​

Retrieve logs with optional query parameters:

  • lines_before: The number of logs before the timestamp or the last log.
  • lines_after: The number of logs after the timestamp.
  • timestamp: The timestamp to start getting logs from.

The default values for all three parameters is 0. With default values, the endpoint returns the last 10 lines of logs.


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curl -X GET \
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"$LANGFLOW_URL/logs?lines_before=0&lines_after=0&timestamp=0" \
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-H "accept: application/json" \
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-H "x-api-key: $LANGFLOW_API_KEY"

Result

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{
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"1736354770500": "2025-01-08T11:46:10.500363-0500 DEBUG Creating starter project Document Q&A\n",
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"1736354770511": "2025-01-08T11:46:10.511146-0500 DEBUG Creating starter project Image Sentiment Analysis\n",
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"1736354770521": "2025-01-08T11:46:10.521018-0500 DEBUG Creating starter project SEO Keyword Generator\n",
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"1736354770532": "2025-01-08T11:46:10.532677-0500 DEBUG Creating starter project Sequential Tasks Agents\n",
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"1736354770544": "2025-01-08T11:46:10.544010-0500 DEBUG Creating starter project Custom Component Generator\n",
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"1736354770555": "2025-01-08T11:46:10.555513-0500 DEBUG Creating starter project Prompt Chaining\n",
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"1736354770588": "2025-01-08T11:46:10.588105-0500 DEBUG Create service ServiceType.CHAT_SERVICE\n",
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"1736354771021": "2025-01-08T11:46:11.021817-0500 DEBUG Telemetry data sent successfully.\n",
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"1736354775619": "2025-01-08T11:46:15.619545-0500 DEBUG Create service ServiceType.STORE_SERVICE\n",
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"1736354775699": "2025-01-08T11:46:15.699661-0500 DEBUG File 046-rocket.svg retrieved successfully from flow /Users/USER/Library/Caches/langflow/profile_pictures/Space.\n"
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}

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