File size: 5,256 Bytes
d8ad0fd
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
import json
from datetime import datetime
from typing import List, Optional, Union

import boto3
from mypy_boto3_logs.client import CloudWatchLogsClient
from pydantic import BaseModel
from retry import retry


class Log(BaseModel, extra="allow"):
    level: str
    location: str
    message: Union[dict, str]
    timestamp: str
    service: str
    cold_start: Optional[bool] = None
    function_name: Optional[str] = None
    function_memory_size: Optional[str] = None
    function_arn: Optional[str] = None
    function_request_id: Optional[str] = None
    xray_trace_id: Optional[str] = None


class LogFetcher:
    def __init__(
        self,
        function_name: str,
        start_time: datetime,
        log_client: Optional[CloudWatchLogsClient] = None,
        filter_expression: Optional[str] = None,
        minimum_log_entries: int = 1,
    ):
        """Fetch and expose Powertools for AWS Lambda (Python) Logger logs from CloudWatch Logs

        Parameters
        ----------
        function_name : str
            Name of Lambda function to fetch logs for
        start_time : datetime
            Start date range to filter traces
        log_client : Optional[CloudWatchLogsClient], optional
            Amazon CloudWatch Logs Client, by default boto3.client('logs)
        filter_expression : Optional[str], optional
            CloudWatch Logs Filter Pattern expression, by default "message"
        minimum_log_entries: int
            Minimum number of log entries to be retrieved before exhausting retry attempts
        """
        self.function_name = function_name
        self.start_time = int(start_time.timestamp())
        self.log_client = log_client or boto3.client("logs")
        self.filter_expression = filter_expression or "message"  # Logger message key
        self.log_group = f"/aws/lambda/{self.function_name}"
        self.minimum_log_entries = minimum_log_entries
        self.logs: List[Log] = self._get_logs()

    def get_log(self, key: str, value: Optional[any] = None) -> List[Log]:
        """Get logs based on key or key and value

        Parameters
        ----------
        key : str
            Log key name
        value : Optional[any], optional
            Log value, by default None

        Returns
        -------
        List[Log]
            List of Log instances
        """
        logs = []
        for log in self.logs:
            log_value = getattr(log, key, None)
            if value is not None and log_value == value:
                logs.append(log)
            elif value is None and hasattr(log, key):
                logs.append(log)
        return logs

    def get_cold_start_log(self) -> List[Log]:
        """Get logs where cold start was true

        Returns
        -------
        List[Log]
            List of Log instances
        """
        return [log for log in self.logs if log.cold_start]

    def have_keys(self, *keys) -> bool:
        """Whether an arbitrary number of key names exist in each log event

        Returns
        -------
        bool
            Whether keys are present
        """
        return all(hasattr(log, key) for log in self.logs for key in keys)

    def _get_logs(self) -> List[Log]:
        ret = self.log_client.filter_log_events(
            logGroupName=self.log_group,
            startTime=self.start_time,
            filterPattern=self.filter_expression,
        )

        if not ret["events"]:
            raise ValueError("Empty response from Cloudwatch Logs. Repeating...")

        filtered_logs = []
        for event in ret["events"]:
            try:
                message = Log(**json.loads(event["message"]))
            except json.decoder.JSONDecodeError:
                continue
            filtered_logs.append(message)

        if len(filtered_logs) < self.minimum_log_entries:
            raise ValueError(
                f"Number of log entries found doesn't meet minimum required ({self.minimum_log_entries}). Repeating...",
            )

        return filtered_logs

    def __len__(self) -> int:
        return len(self.logs)


@retry(ValueError, delay=2, jitter=1.5, tries=10)
def get_logs(
    function_name: str,
    start_time: datetime,
    minimum_log_entries: int = 1,
    filter_expression: Optional[str] = None,
    log_client: Optional[CloudWatchLogsClient] = None,
) -> LogFetcher:
    """_summary_

    Parameters
    ----------
    function_name : str
        Name of Lambda function to fetch logs for
    start_time : datetime
        Start date range to filter traces
    minimum_log_entries : int
        Minimum number of log entries to be retrieved before exhausting retry attempts
    log_client : Optional[CloudWatchLogsClient], optional
        Amazon CloudWatch Logs Client, by default boto3.client('logs)
    filter_expression : Optional[str], optional
        CloudWatch Logs Filter Pattern expression, by default "message"

    Returns
    -------
    LogFetcher
        LogFetcher instance with logs available as properties and methods
    """
    return LogFetcher(
        function_name=function_name,
        start_time=start_time,
        filter_expression=filter_expression,
        log_client=log_client,
        minimum_log_entries=minimum_log_entries,
    )