CloudWatch Logs Insights で Lambda のログで検出されるフィールドの値を確認してみた

CloudWatch Logs Insightsで知らないフィールドがあったので、内容を確認してみました。

藤井元貴

2024.12.20

CloudWatch Logs Insightsでは、標準的なフィールドに加えて、各サービスに合わせたフィールドも利用できます。
サポートされるログと検出されるフィールド - Amazon CloudWatch ログ
本記事では、Lambdaのログで検出されるフィールドの値がどうなっているかを確認してみました。
@timestamp
@logStream
@log
@message
@requestId
@duration
@billedDuration
@type
@memorySize
@maxMemoryUsed
なお、X-RayのトレースIDがログに含まれている場合は、下記も利用できます。本記事では省略します。
@xrayTraceId
@xraySegmentId
 おすすめの方CloudWatch Logs Insights で Lambda のログで検出されるフィールドの値を知りたい方
 適当なLambdaを用意し、実行しておく関数名: manulaly-test-function
メモリ: 128 MB
def lambda_handler(event, context):
    print('botocore vertion is {0}'.format(botocore.__version__))
    print('boto3 vertion is {0}'.format(boto3.__version__))
    print('hello')
 CloudWatch Logs Insights でログを確認する CloudWatch Logsの内容
 クエリfields @timestamp, @message, @logStream, @log, @requestId, @duration, @billedDuration, @type, @memorySize, @maxMemoryUsed
| sort @timestamp asc
| limit 10
 クエリの実行結果（JSON）[
    {
        "@timestamp": "2024-12-19 09:07:09.842",
        "@message": "INIT_START Runtime Version: python:3.7.v63\tRuntime Version ARN: arn:aws:lambda:ap-northeast-1::runtime:0452c013930b7a2594d5a8c146cc40d115ed83e2398bb66f3049298c64c7a327\n",
        "@logStream": "2024/12/19/[$LATEST]b196eecb1aa640edbf655ec5cd35d295",
        "@log": "123456789123:/aws/lambda/manulaly-test-function",
        "@requestId": "",
        "@duration": "",
        "@billedDuration": "",
        "@type": "",
        "@memorySize": "",
        "@maxMemoryUsed": ""
    },
    {
        "@timestamp": "2024-12-19 09:07:10.293",
        "@message": "START RequestId: 62f15eee-b3bc-468a-a4a3-72d7caafdc50 Version: $LATEST\n",
        "@logStream": "2024/12/19/[$LATEST]b196eecb1aa640edbf655ec5cd35d295",
        "@log": "123456789123:/aws/lambda/manulaly-test-function",
        "@requestId": "62f15eee-b3bc-468a-a4a3-72d7caafdc50",
        "@duration": "",
        "@billedDuration": "",
        "@type": "START",
        "@memorySize": "",
        "@maxMemoryUsed": ""
    },
    {
        "@timestamp": "2024-12-19 09:07:10.294",
        "@message": "botocore vertion is 1.29.90\n",
        "@logStream": "2024/12/19/[$LATEST]b196eecb1aa640edbf655ec5cd35d295",
        "@log": "123456789123:/aws/lambda/manulaly-test-function",
        "@requestId": "",
        "@duration": "",
        "@billedDuration": "",
        "@type": "",
        "@memorySize": "",
        "@maxMemoryUsed": ""
    },
    {
        "@timestamp": "2024-12-19 09:07:10.294",
        "@message": "boto3 vertion is 1.26.90\n",
        "@logStream": "2024/12/19/[$LATEST]b196eecb1aa640edbf655ec5cd35d295",
        "@log": "123456789123:/aws/lambda/manulaly-test-function",
        "@requestId": "",
        "@duration": "",
        "@billedDuration": "",
        "@type": "",
        "@memorySize": "",
        "@maxMemoryUsed": ""
    },
    {
        "@timestamp": "2024-12-19 09:07:10.294",
        "@message": "hello\n",
        "@logStream": "2024/12/19/[$LATEST]b196eecb1aa640edbf655ec5cd35d295",
        "@log": "123456789123:/aws/lambda/manulaly-test-function",
        "@requestId": "",
        "@duration": "",
        "@billedDuration": "",
        "@type": "",
        "@memorySize": "",
        "@maxMemoryUsed": ""
    },
    {
        "@timestamp": "2024-12-19 09:07:10.310",
        "@message": "END RequestId: 62f15eee-b3bc-468a-a4a3-72d7caafdc50\n",
        "@logStream": "2024/12/19/[$LATEST]b196eecb1aa640edbf655ec5cd35d295",
        "@log": "123456789123:/aws/lambda/manulaly-test-function",
        "@requestId": "62f15eee-b3bc-468a-a4a3-72d7caafdc50",
        "@duration": "",
        "@billedDuration": "",
        "@type": "END",
        "@memorySize": "",
        "@maxMemoryUsed": ""
    },
    {
        "@timestamp": "2024-12-19 09:07:10.310",
        "@message": "REPORT RequestId: 62f15eee-b3bc-468a-a4a3-72d7caafdc50\tDuration: 14.17 ms\tBilled Duration: 15 ms\tMemory Size: 128 MB\tMax Memory Used: 71 MB\tInit Duration: 450.55 ms\t\n",
        "@logStream": "2024/12/19/[$LATEST]b196eecb1aa640edbf655ec5cd35d295",
        "@log": "123456789123:/aws/lambda/manulaly-test-function",
        "@requestId": "62f15eee-b3bc-468a-a4a3-72d7caafdc50",
        "@duration": "14.17",
        "@billedDuration": "15",
        "@type": "REPORT",
        "@memorySize": "128000000",
        "@maxMemoryUsed": "71000000"
    }
]
 ログフィールドの値を整理

名前
値
備考


timestamp
時刻（UTC）


message
ログの内容


logStream
ログストリーム名


log
ロググループ名 +α


requestId
リクエストID
START,END,REPORTのみ

duration
Duration (ms)
REPORTのみ

billedDuration
Billed Duration (ms)
REPORT のみ

type
START or END or REPORT
START,END,REPORTのみ

memorySize
Memory Size (Byte)
REPORTのみ

maxMemoryUsed
Max Memory Used (Byte)
REPORTのみ

 おまけ：LambdaのログフォーマットがJSONの場合 CloudWatch Logsの内容
 クエリの実行結果（JSON）「@message」の内容がJSONになっていますが、それ以外は同じです。
※一部、print()を利用してたせいで、JSONではないメッセージがあります。
[
    {
        "@timestamp": "2024-12-19 09:21:02.785",
        "@message": {
            "time": "2024-12-19T09:21:02.785Z",
            "type": "platform.initStart",
            "record": {
                "initializationType": "on-demand",
                "phase": "init",
                "runtimeVersion": "python:3.7.v63",
                "runtimeVersionArn": "arn:aws:lambda:ap-northeast-1::runtime:0452c013930b7a2594d5a8c146cc40d115ed83e2398bb66f3049298c64c7a327",
                "functionName": "manulaly-test-function",
                "functionVersion": "$LATEST"
            }
        },
        "@logStream": "2024/12/19/manulaly-test-function[$LATEST]dab4faee987c426bb21ba644bb0a97b6",
        "@log": "123456789123:/aws/lambda/manulaly-test-function",
        "@requestId": "",
        "@duration": "",
        "@billedDuration": "",
        "@type": "",
        "@memorySize": "",
        "@maxMemoryUsed": ""
    },
    {
        "@timestamp": "2024-12-19 09:21:03.236",
        "@message": {
            "time": "2024-12-19T09:21:03.236Z",
            "type": "platform.start",
            "record": {
                "requestId": "b12aeec0-cbd2-420c-a0f6-5753d5b3fd6e",
                "version": "$LATEST"
            }
        },
        "@logStream": "2024/12/19/manulaly-test-function[$LATEST]dab4faee987c426bb21ba644bb0a97b6",
        "@log": "123456789123:/aws/lambda/manulaly-test-function",
        "@requestId": "b12aeec0-cbd2-420c-a0f6-5753d5b3fd6e",
        "@duration": "",
        "@billedDuration": "",
        "@type": "START",
        "@memorySize": "",
        "@maxMemoryUsed": ""
    },
    {
        "@timestamp": "2024-12-19 09:21:03.237",
        "@message": "botocore vertion is 1.29.90\n",
        "@logStream": "2024/12/19/manulaly-test-function[$LATEST]dab4faee987c426bb21ba644bb0a97b6",
        "@log": "123456789123:/aws/lambda/manulaly-test-function",
        "@requestId": "",
        "@duration": "",
        "@billedDuration": "",
        "@type": "",
        "@memorySize": "",
        "@maxMemoryUsed": ""
    },
    {
        "@timestamp": "2024-12-19 09:21:03.237",
        "@message": "boto3 vertion is 1.26.90\n",
        "@logStream": "2024/12/19/manulaly-test-function[$LATEST]dab4faee987c426bb21ba644bb0a97b6",
        "@log": "123456789123:/aws/lambda/manulaly-test-function",
        "@requestId": "",
        "@duration": "",
        "@billedDuration": "",
        "@type": "",
        "@memorySize": "",
        "@maxMemoryUsed": ""
    },
    {
        "@timestamp": "2024-12-19 09:21:03.237",
        "@message": "hello\n",
        "@logStream": "2024/12/19/manulaly-test-function[$LATEST]dab4faee987c426bb21ba644bb0a97b6",
        "@log": "123456789123:/aws/lambda/manulaly-test-function",
        "@requestId": "",
        "@duration": "",
        "@billedDuration": "",
        "@type": "",
        "@memorySize": "",
        "@maxMemoryUsed": ""
    },
    {
        "@timestamp": "2024-12-19 09:21:03.259",
        "@message": {
            "time": "2024-12-19T09:21:03.259Z",
            "type": "platform.report",
            "record": {
                "requestId": "b12aeec0-cbd2-420c-a0f6-5753d5b3fd6e",
                "metrics": {
                    "durationMs": 20.421,
                    "billedDurationMs": 21,
                    "memorySizeMB": 128,
                    "maxMemoryUsedMB": 71,
                    "initDurationMs": 449.447
                },
                "status": "success"
            }
        },
        "@logStream": "2024/12/19/manulaly-test-function[$LATEST]dab4faee987c426bb21ba644bb0a97b6",
        "@log": "123456789123:/aws/lambda/manulaly-test-function",
        "@requestId": "b12aeec0-cbd2-420c-a0f6-5753d5b3fd6e",
        "@duration": "20.421",
        "@billedDuration": "21",
        "@type": "REPORT",
        "@memorySize": "128000000",
        "@maxMemoryUsed": "71000000"
    }
]
 さいごにREPORT行のみ調べたい場合などは、「@type」を使えば便利そうです。
 参考サポートされるログと検出されるフィールド - Amazon CloudWatch ログ

CloudWatch Logs Insights で Lambda のログで検出されるフィールドの値を確認してみた

おすすめの方

適当なLambdaを用意し、実行しておく

CloudWatch Logs Insights でログを確認する

CloudWatch Logsの内容

クエリ

クエリの実行結果（JSON）

ログフィールドの値を整理

おまけ：LambdaのログフォーマットがJSONの場合

CloudWatch Logsの内容

クエリの実行結果（JSON）

さいごに

参考

主なカテゴリ

AWS

おすすめ

プロダクト

コンテンツ

お問い合わせ

運営会社

名前	値	備考
timestamp	時刻（UTC）
message	ログの内容
logStream	ログストリーム名
log	ロググループ名 +α
requestId	リクエストID	START,END,REPORTのみ
duration	Duration (ms)	REPORTのみ
billedDuration	Billed Duration (ms)	REPORT のみ
type	START or END or REPORT	START,END,REPORTのみ
memorySize	Memory Size (Byte)	REPORTのみ
maxMemoryUsed	Max Memory Used (Byte)	REPORTのみ