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Diffstat (limited to 'src/mlia/backend/output_consumer.py')
-rw-r--r-- | src/mlia/backend/output_consumer.py | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/src/mlia/backend/output_consumer.py b/src/mlia/backend/output_consumer.py new file mode 100644 index 0000000..bac4186 --- /dev/null +++ b/src/mlia/backend/output_consumer.py @@ -0,0 +1,66 @@ +# SPDX-FileCopyrightText: Copyright 2022, Arm Limited and/or its affiliates. +# SPDX-License-Identifier: Apache-2.0 +"""Output consumers module.""" +import base64 +import json +import re +from typing import List +from typing import Protocol +from typing import runtime_checkable + + +@runtime_checkable +class OutputConsumer(Protocol): + """Protocol to consume output.""" + + def feed(self, line: str) -> bool: + """ + Feed a new line to be parsed. + + Return True if the line should be removed from the output. + """ + + +class Base64OutputConsumer(OutputConsumer): + """ + Parser to extract base64-encoded JSON from tagged standard output. + + Example of the tagged output: + ``` + # Encoded JSON: {"test": 1234} + <metrics>eyJ0ZXN0IjogMTIzNH0</metrics> + ``` + """ + + TAG_NAME = "metrics" + + def __init__(self) -> None: + """Set up the regular expression to extract tagged strings.""" + self._regex = re.compile(rf"<{self.TAG_NAME}>(.*)</{self.TAG_NAME}>") + self.parsed_output: List = [] + + def feed(self, line: str) -> bool: + """ + Parse the output line and save the decoded output. + + Returns True if the line contains tagged output. + + Example: + Using the tagged output from the class docs the parser should collect + the following: + ``` + [ + {"test": 1234} + ] + ``` + """ + res_b64 = self._regex.search(line) + if res_b64: + res_json = base64.b64decode(res_b64.group(1), validate=True) + res = json.loads(res_json) + self.parsed_output.append(res) + # Remove this line from the output, i.e. consume it, as it + # does not contain any human readable content. + return True + + return False |