read_csv 不是逐行发生的

Question

我正在尝试读取一个 csv 文件。但是，在打印期间，它不是逐行读取，而是遍历一些内部循环并复制结果。

- name: read csv
  read_csv:
    path: /u00/app/monitor/newrelic_test.csv
    key: Application   
  register: newrelic

- name: Print newrelic var   
  ansible.builtin.debug:
    var: newrelic.list

输出如下所示：

  [testserver1] =>
"newrelic.list": 
        "Application": "Microsoft",
        "env": "Test",
        "Datacenter": "DC1",
        "Hostname": "testserver1",
    },
        "Application": "Apple",
        "env": "Test",
        "Datacenter": "DC2",
        "Hostname": "testserver2",
    }
[testserver2] => {
"newrelic.list": 
    {
        "Application": "Microsoft",
        "env": "Test",
        "Datacenter": "DC1",
        "Hostname": "testserver1",
    },
        "Application": "Apple",
        "env": "Test",
        "Datacenter": "DC2",
        "Hostname": "testserver2",
    }
]

.csv 文件：

Application,env,Datacenter,Hostname
Microsoft,Test,DC1,testserver1
Apple,Test,DC2,testserver2

预期结果应为：

[testserver1] =>
"newrelic.list": 
        "Application": "Microsoft",
        "env": "Test",
        "Datacenter": "DC1",
        "Hostname": "testserver1",
    }
[testserver2] => {
"newrelic.list": 
    {
        "Application": "Apple",
        "env": "Test",
        "Datacenter": "DC2",
        "Hostname": "testserver2",
    }
]

编辑：-下一个块

- name: copy template
  template:
    src: /u00/ansible/Playbooks/files/infra-config.yml_template
    dest: /u00/app/monitor/infra-config.yml
  loop: "{{ newrelic.list }}"
  loop_control:
    loop_var: item

问题：如果未使用newrelic.list，则会出现如下错误：

[testserver1]: FAILED! => {"msg": "Invalid data passed to 'loop', it requires a list, got this instead: {'dict': 

我尝试添加 dict2items 但随后模板无法读取项目。

Answer 1

read_csv 模块不会“逐行”读取 CSV 文件；来自the documentation：

读取 [s] 一个 CSV 文件并返回 [s] 一个列表或字典，每行包含一个字典。

所以当你运行这个任务时：

- name: read csv
  read_csv:
    path: data.csv
    key: Application
  register: newrelic

您得到一个变量 newrelic，它有一个空的 list 元素和一个 dict 元素，其中包含来自 CSV 文件的数据，由 Application 键入（因为这就是您要求的）。如果使用 debug 任务查看 newrelic 的值，我们会看到：

ok: [localhost] => {
    "newrelic": {
        "changed": false,
        "dict": {
            "Apple": {
                "Application": "Apple",
                "Datacenter": "DC2",
                "Hostname": "testserver2",
                "env": "Test"
            },
            "Microsoft": {
                "Application": "Microsoft",
                "Datacenter": "DC1",
                "Hostname": "testserver1",
                "env": "Test"
            }
        },
        "failed": false,
        "list": []
    }
}

目前尚不清楚您在这里究竟想做什么，但如果您想通过清单主机名从 CSV 文件中查找值，则需要将其键入 Hostname 而不是：

- name: read csv
  read_csv:
    path: data.csv
    key: Hostname
  register: newrelic

然后你可以写：

- name: Print newrelic var
  ansible.builtin.debug:
    var: newrelic.dict[inventory_hostname]

假设您的清单中有主机 testserver1 和 testserver2，则剧本如下：

- hosts: localhost
  gather_facts: false
  tasks:
    - name: read csv
      read_csv:
        path: data.csv
        key: Hostname
      register: newrelic

- hosts: all
  gather_facts: false
  tasks:
    - name: Print newrelic var
      ansible.builtin.debug:
        var: hostvars.localhost.newrelic.dict[inventory_hostname]

将导致此输出：

PLAY [localhost] ***************************************************************

TASK [read csv] ****************************************************************
ok: [localhost]

PLAY [all] *********************************************************************

TASK [Print newrelic var] ******************************************************
ok: [testserver1] => {
    "hostvars.localhost.newrelic.dict[inventory_hostname]": {
        "Application": "Microsoft",
        "Datacenter": "DC1",
        "Hostname": "testserver1",
        "env": "Test"
    }
}
ok: [testserver2] => {
    "hostvars.localhost.newrelic.dict[inventory_hostname]": {
        "Application": "Apple",
        "Datacenter": "DC2",
        "Hostname": "testserver2",
        "env": "Test"
    }
}

PLAY RECAP *********************************************************************
localhost                  : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   
testserver1                : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   
testserver2                : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0