Terraform：如何合并三个列表以构建映射列表

原代码尝试将告警名称、对应阈值与每个SQS队列进行组合，但输出不符合预期：

locals {
    alarms = {
        names = ["NumberOfMessagesReceived", "NumberOfMessagesDeleted", "ApprNumberOfMessagesDelayed",
                 "NumberOfMessagesSent", "NumberOfEmptyReceives", "ApprNumberOfMessagesNotVisible"],

        thresholds = ["1000", "50", "100", "100", "100", "50"]
    }

    sqs_queues = {
        queues = ["default", "general"]
    }

    alarms2 = flatten([
        for name, threshold in local.alarms : [
            for sqs_queue in local.sqs_queues : {
                alarm_name = name
                threshold_value = threshold
                sqs_queue_name = sqs_queue
            }
        ]
    ])
}

预期输出要求每个告警名称与对应阈值绑定，再分别和每个SQS队列组合，示例：

alarm_name = "NumberOfMessagesReceived"
threshold_value = "1000"
sqs_queue_name = "default"

alarm_name = "NumberOfMessagesReceived"
threshold_value = "1000"
sqs_queue_name = "general"

原代码错误地遍历了local.alarms这个map的键值对，此时name会取到"names"和"thresholds"两个字符串，threshold则是对应的整个列表，无法实现名称与阈值的一一配对。

需要先将names和thresholds按索引配对成告警条目，再将每个条目与所有SQS队列组合：

locals {
    alarms = {
        names = ["NumberOfMessagesReceived", "NumberOfMessagesDeleted", "ApprNumberOfMessagesDelayed",
                 "NumberOfMessagesSent", "NumberOfEmptyReceives", "ApprNumberOfMessagesNotVisible"],

        thresholds = ["1000", "50", "100", "100", "100", "50"]
    }

    sqs_queues = {
        queues = ["default", "general"]
    }

    # 先将名称和阈值按索引配对成单个告警对象
    alarm_entries = [
        for idx, name in local.alarms.names : {
            name = name
            threshold = local.alarms.thresholds[idx]
        }
    ]

    # 遍历每个告警条目，再绑定每个SQS队列，最后展平结果
    alarms2 = flatten([
        for entry in local.alarm_entries : [
            for queue in local.sqs_queues.queues : {
                alarm_name = entry.name
                threshold_value = entry.threshold
                sqs_queue_name = queue
            }
        ]
    ])
}

修正后的local.alarms2会生成预期的结构，每个告警名称+阈值的组合都会分别与"default"和"general"队列关联，完全符合需求。

内容的提问来源于stack exchange，提问作者Rad4