File "packages/prefect/server/models/block_documents.py", line 406, in read_block_documents
root_block_document = await BlockDocument.from_orm_model(
                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "packages/prefect/server/schemas/core.py", line 819, in from_orm_model
data = await orm_block_document.decrypt_data(session=session)
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "packages/prefect/server/database/orm_models.py", line 1057, in decrypt_data
return await decrypt_fernet(session, self.data)
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "packages/prefect/server/utilities/encryption.py", line 49, in decrypt_fernet
return json.loads(fernet.decrypt(byte_blob).decode())
                  ^^^^^^^^^^^^^^^^^^^^^^^^^
File "packages/cryptography/fernet.py", line 89, in decrypt
return self._decrypt_data(data, timestamp, time_info)
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "packages/cryptography/fernet.py", line 148, in _decrypt_data
self._verify_signature(data)
File "packages/cryptography/fernet.py", line 132, in _verify_signature
raise InvalidToken
cryptography.fernet.InvalidToken

@Marvin in the middle of a run why does sometimes it stop being able to read the block? nothing has changed

The

InvalidToken

error you're encountering during the decryption process in Prefect can be quite frustrating. This error typically indicates that the token used for decryption is invalid, which could be due to several reasons: 1. Key Mismatch: The Fernet key used for encryption might differ from the one used for decryption. Ensure that the correct key is being used consistently across sessions. 2. Data Corruption: The data you're trying to decrypt might have been altered or corrupted. Check if there were any unintended changes to the encrypted data. 3. Version Mismatch: Ensure that you are running the latest version of Prefect, as issues might have been resolved in newer releases. Prefect Troubleshooting Guide If none of these seem to be the issue, you might want to review your flow's logs for any anomalies or reach out to Prefect support with detailed logs and environment information.

@Marvin when would the data be corruped? i’m just running a flow i’m serving locally so i dont think its a key mismatch since theres only one thing. theres no version issues either. like it worked earlier in the flow and then failed later in the same flow

Data corruption during a flow run can occur due to several possible reasons, even in a local execution environment. Here are a few scenarios that might lead to such issues: 1. Concurrency Issues: If multiple processes or threads are trying to access or modify the data simultaneously, it could lead to inconsistencies or corruption. Ensure that your flow doesn't have concurrent writes to the same data unless properly synchronized. 2. Intermediate State Changes: If the flow modifies the data in intermediate steps and those changes are not correctly handled or reverted, it could lead to corruption. 3. Resource Constraints: Running out of memory or disk space might lead to incomplete writes or corrupted data being saved. 4. External Dependencies: If your flow relies on external systems or files, any changes or failures in those systems during execution could result in data corruption. Unfortunately, without specific logs or a detailed view of the flow's operations, pinpointing the exact cause can be challenging. Reviewing the flow's logs for any anomalies or unexpected behavior around the time of failure might provide further insights. If the issue persists, consider isolating parts of the flow to identify the problematic section.

@Marvin ok, thats helpful. but what exactly is the data being corrupted?

The data being corrupted in your scenario likely pertains to the

BlockDocument

or

ORMBlockDocument

classes within Prefect's ORM models. These classes handle the storage and retrieval of block documents, which are used to store configuration or state information for different parts of a Prefect flow. Corruption in this context means that the data stored in these block documents might be altered or unreadable, leading to the

InvalidToken

error during decryption. This could affect how your flow accesses configuration data or other critical information it needs to execute correctly. For more details on these classes, you can explore the Prefect source code, particularly the orm_models module.

@Marvin how can i check if a block exists using the prefect python client

To check if a block exists in Prefect, you can use the Prefect CLI or API to list and inspect available block types and documents. Here's a concise way to do it: 1. Using the Prefect CLI: - To list all available block types, you can run:

bash
     prefect block type ls

- This will show all registered block types. You can then check for specific block documents related to these types in the Prefect UI or via the API. 2. Using the Prefect API: - You can programmatically retrieve block documents and check their existence by querying the API for block documents of a specific type or name. For more detailed management and interaction with blocks, refer to the Prefect Blocks Documentation. This will guide you through creating, updating, and managing block documents through both the UI and API.