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https://github.com/langchain-ai/langgraph.git
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bce4545021
- PR branch for testing w/ typescript (@benjamincburns ) - implementation needs better cache invalidation for the cassettes (@eyurtsev) --------- Co-authored-by: Ben Burns <803016+benjamincburns@users.noreply.github.com>
109 lines
4.2 KiB
Python
109 lines
4.2 KiB
Python
import base64
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import os
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import zlib
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from logging import getLogger
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from types import TracebackType
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from typing import Optional, Any, Type
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import msgpack
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import vcr
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logger = getLogger(__name__)
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os.environ.pop("LANGCHAIN_TRACING_V2", None)
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custom_vcr = vcr.VCR()
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def compress_data(data: Any, compression_level: int = 9) -> str:
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packed = msgpack.packb(data, use_bin_type=True)
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compressed = zlib.compress(packed, level=compression_level)
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return base64.b64encode(compressed).decode("utf-8")
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def decompress_data(compressed_string: str) -> Any:
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decoded = base64.b64decode(compressed_string)
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decompressed = zlib.decompress(decoded)
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return msgpack.unpackb(decompressed, raw=False)
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class AdvancedCompressedSerializer:
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def serialize(self, cassette_dict: Any) -> str:
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return compress_data(cassette_dict)
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def deserialize(self, cassette_string: str) -> Any:
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return decompress_data(cassette_string)
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custom_vcr.register_serializer("advanced_compressed", AdvancedCompressedSerializer())
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custom_vcr.serializer = "advanced_compressed"
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class HashedCassette:
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def __init__(self, cassette_path: str, hash_value: str) -> None:
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"""A context manager for using VCR cassettes with an embedded hash value.
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Args:
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cassette_path (str): The file path of the cassette (independent of hash).
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hash_value (str): The expected hash value (e.g. a uuid string).
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This class provides a context manager for using VCR cassettes with an embedded hash value.
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The hash value is used to ensure that the cassette matches the expected state, and if not,
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the cassette is removed or updated with the new hash value.
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"""
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self.cassette_path: str = cassette_path
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self.hash_value: str = hash_value
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self.vcr: vcr.VCR = custom_vcr
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self.cassette_context: Optional[Any] = None
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def __enter__(self) -> Any:
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# Get the serializer instance from the VCR instance.
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serializer = self.vcr.serializers[self.vcr.serializer]
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# If the cassette file exists, check its embedded hash.
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if os.path.exists(self.cassette_path):
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with open(self.cassette_path, "r") as f:
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content = f.read()
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try:
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cassette_data = serializer.deserialize(content)
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except Exception as e:
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print(f"Error deserializing cassette, removing file: {e}")
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os.remove(self.cassette_path)
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else:
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existing_hash = cassette_data.get("cassette_hash")
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if existing_hash != self.hash_value:
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print("Hash mismatch. Removing outdated cassette.")
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os.remove(self.cassette_path)
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# Now enter the VCR cassette context.
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self.cassette_context = custom_vcr.use_cassette(
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self.cassette_path,
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filter_headers=["x-api-key", "authorization"],
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record_mode="once",
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serializer="advanced_compressed",
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)
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return self.cassette_context.__enter__()
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def __exit__(
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self,
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exc_type: Optional[Type[BaseException]] = None,
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exc_val: Optional[BaseException] = None,
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exc_tb: Optional[TracebackType] = None,
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) -> Optional[bool]:
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# Exit the VCR cassette context.
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result = self.cassette_context.__exit__(exc_type, exc_val, exc_tb)
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serializer = self.vcr.serializers[self.vcr.serializer]
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# If a cassette was recorded (or updated), open and update its hash.
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if os.path.exists(self.cassette_path):
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with open(self.cassette_path, "r") as f:
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content = f.read()
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try:
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cassette_data = serializer.deserialize(content)
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except Exception as e:
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logger.error(f"Error deserializing cassette during exit: {e}")
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return result
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# Update the cassette data with the expected hash.
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if cassette_data.get("cassette_hash") != self.hash_value:
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cassette_data["cassette_hash"] = self.hash_value
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serialized_data = serializer.serialize(cassette_data)
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with open(self.cassette_path, "w") as f:
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f.write(serialized_data)
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return result
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