download entire aws cloudwatch log

download-cloudwatch-logs.sh

#!/bin/bash

# THIS SCRIPT DEPENDS ON:
# aws cli: https://aws.amazon.com/cli/
# jq https://stedolan.github.io/jq/ | $ brew install jq

i=0
NEXT_ID=""
GROUP_NAME="/aws/lambda/prod-some-service"
STREAM_NAME="2022/08/03/[\$LATEST]some-id"

while [ true ]
do
    if [ "$NEXT_ID" != "" ]; then
        $(aws logs get-log-events \
            --log-group-name $GROUP_NAME \
            --log-stream-name $STREAM_NAME \
            --start-from-head \
            --next-token $NEXT_ID \
            > log-$i.json)
    else
        $(aws logs get-log-events \
            --log-group-name $GROUP_NAME \
            --log-stream-name $STREAM_NAME \
            --start-from-head \
            > log-$i.json)
    fi

    NEXT_ID=$(cat log-$i.json | jq -r '.nextForwardToken')
    EVENTS=$(cat log-$i.json | jq -r '.events | length')

    echo "batch #$(( $i + 1)) done!"
    echo "next_id: $NEXT_ID\n"

    # even when $EVENTS == 0, for some reason aws returns a $NEXT_ID
    if [ "$NEXT_ID" == "" ] | [ "$EVENTS" == "0" ]; then
        unlink log-$i.json
        break
    fi

    i=$((i + 1))
done

echo "done"