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我是 rego 的新手，并试图编写一个策略来验证列表中的元素是否与另一个列表相对应。这是我要解决的问题：我有一个已批准的安全组列表，我需要根据我的输入检查安全组。如果我输入的 SG 不在批准列表中，我需要输出一条消息说“正在使用无效的 SG”。我找不到任何说明如何将一个列表与另一个列表进行比较的文档。这是 rego 游乐场的政策：https ://play.openpolicyagent.org/p/m09f2K1g0h

政策：

check_list = ["sg-1001a1d199tx8866a","sg-2002b2e200in9966b", "sg-3003c3f201dc0011c","sg-4004d4e202nj1122d", "sg-5003c3f201dc0011e","sg-6004d4e202nj1122f"]

aws_valid_sgs := {i: Reason |
    doc = input[i]; i="aws_launch_configuration.ecs-cluster-lc"
    key_ids := [k | doc[k]; startswith(k, "security_groups.")]
    resource := {
        doc[k] : doc[replace(k, ".key", ".value")] | key_ids[_] == k
    }
    
    sg_ids := [m | resource[m]; startswith(m, "sg-")]
    list := {x| x:=check_list[_]}

    not(list[sg_ids[i]])

    Reason := sprintf("Resource %v is not using an approved SG ", [doc.name])
}

输入：

{
    "aws_launch_configuration.ecs-cluster-lc": {
        "associate_public_ip_address": "false",
        "destroy": false,
        "destroy_tainted": false,
        "ebs_block_device.#": "",
        "ebs_optimized": "",
        "enable_monitoring": "true",
        "id": "",
        "instance_type": "t3.large",
        "key_name": "",
        "name": "test_r1-us-east-1",
        "security_groups.1122334455": "sg-1001a1d199tx8866a",
        "security_groups.2233445566": "sg-2002b2e200in9966b",
        "security_groups.3344556677": "sg-3003c3f201dc0011c",
        "security_groups.4455667788": "sg-4004d4e202nj1122d"
    },
    "destroy": false
}

任何帮助表示赞赏。谢谢。

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1 回答 1

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TLDR；这最好使用集合操作来完成，例如{"foo", "bar", "baz"} - {"bar"} == {"foo", "baz"})。这是一个完整的例子：


# Define a SET of valid SGs to compare against.
valid_sgs := {"sg-1001a1d199tx8866a","sg-2002b2e200in9966b", "sg-3003c3f201dc0011c","sg-4004d4e202nj1122d", "sg-5003c3f201dc0011e","sg-6004d4e202nj1122f"}

# Compute the SET of SGs from the launch configuration in the input.
launch_config_sgs := {sg |
    some key
    launch_config := input["aws_launch_configuration.ecs-cluster-lc"]
    sg := launch_config[key]
    startswith(key, "security_groups.")
}

# Compute the SET of invalid SGs by taking the difference of the other two sets.
invalid_launch_config_sgs := launch_config_sgs - valid_sgs

# Generate a 'deny' message if there are any invalid SGs.
deny[msg] {
    launch_config := input["aws_launch_configuration.ecs-cluster-lc"]
    count(invalid_launch_config_sgs) > 0
    msg := sprintf("Resource %v is not using an approved SG", [launch_config.name])
}

游乐场链接

海报版本有几件事使问题变得比必要的更难：

  • check_list被定义为一个数组（不是一个集合）。数组按位置索引。要检查列表中是否包含值，您需要迭代. 构建集合并测试成员/交集/差异/等通常更容易。

  • 该aws_valid_sgs规则从输入中构造了一堆不必要的中间值（例如，, ,doc等）。所需要的只是输入中的一组 SG，可以在 2 个语句中计算：在启动配置中查找键开始的字段并为这些键构造一组字段值。key_idsresourcesecurity_group.

于 2020-08-12T13:16:54.850 回答