Jinja - 如何将动态范围传递给表达式？答案

【问题标题】：Jinja - How to pass on dynamic range to an expression?Jinja - 如何将动态范围传递给表达式？
【发布时间】：2022-11-23 16:53:53
【问题描述】：

我有一个 csv 文件，我正在使用 Ansible read_csv 将其作为字典阅读

id,name,quantity,type
1,apple,10,fruit
2,orange,20,fruit
3,carrot,5,veg
4,beetroot,2,veg
5,onion,3,veg
6,tomato,4,both
7,pear,4,fruit
8,banana,6,fruit
9,persimon,4,fruit
10,guava,4,fruit
11,pepper,4,veg
12,potato,5,veg
13,cherry,5,fruit

等价的字典变成

"{'1': {'id': '1', 'name': 'apple', 'quantity': '10', 'type': 'fruit'}, '2': {'id': '2', 'name': 'orange', 'quantity': '20', 'type': 'fruit'}, '3': {'id': '3', 'name': 'carrot', 'quantity': '5', 'type': 'veg'}, '4': {'id': '4', 'name': 'beetroot', 'quantity': '2', 'type': 'veg'}, '5': {'id': '5', 'name': 'onion', 'quantity': '3', 'type': 'veg'}, '6': {'id': '6', 'name': 'tomato', 'quantity': '4', 'type': 'both'}, '7': {'id': '7', 'name': 'pear', 'quantity': '4', 'type': 'fruit'}, '8': {'id': '8', 'name': 'banana', 'quantity': '6', 'type': 'fruit'}, '9': {'id': '9', 'name': 'persimon', 'quantity': '4', 'type': 'fruit'}, '10': {'id': '10', 'name': 'guava', 'quantity': '4', 'type': 'fruit'}, '11': {'id': '11', 'name': 'pepper', 'quantity': '4', 'type': 'veg'}, '12': {'id': '12', 'name': 'potato', 'quantity': '5', 'type': 'veg'}, '13': {'id': '13', 'name': 'cherry', 'quantity': '5', 'type': 'fruit'}}"

我的逻辑是将列表分成批次，每次 2 个名称所以我要找的输出是["carrot", "beetroot"], ["onion", "pepper"]等等

当我在 jinja 表达式中对 [0:2] 范围进行硬编码时，以下逻辑完美运行

{% set my_fruit_list = [] %}
{%- for item in (fruits_dict.dict| dict2items | selectattr("value.type", "match", "^veg$"))[0:2]  -%}
{{ my_fruit_list.append(item.value.name) }}
{%- endfor -%}
my_list=["{{ my_fruit_list|join('", "') }}"]

但是当我尝试将其更改为动态变量时，它不起作用。我在下面试过

{% set input_range = "[0:2]" %}
{%- for item in (fruits_dict.dict| dict2items | selectattr("value.type", "match", "^veg$"))input_range  -%}

有什么办法可以将“input_range”作为动态参数传递给表达式吗？

还有没有更好的方法来获取 selectattr 而无需将 csv 转换为 dict 和 dict2items ？

【问题讨论】：

"it doesn't work" is not an accurate description of the problem you're facing

标签： ansible jinja2

【解决方案1】：

简而言之：

{% set my_fruit_list = [] %}
{% set fruit_start = 0 %}
{% set fruit_end = 1 %}
{%- for item in (fruits_dict.dict| dict2items | selectattr("value.type", "match", "^veg$"))[fruit_start:fruit_end]  -%}
{{ my_fruit_list.append(item.value.name) }}
{%- endfor -%}
my_list=["{{ my_fruit_list|join('", "') }}"]

【讨论】：

【解决方案2】：

^{鉴于文件
shell> cat /tmp/fruits.csv
id,name,quantity,type
1,apple,10,fruit
2,orange,20,fruit
3,carrot,5,veg
4,beetroot,2,veg
5,onion,3,veg
6,tomato,4,both
7,pear,4,fruit
8,banana,6,fruit
9,persimon,4,fruit
10,guava,4,fruit
11,pepper,4,veg
12,potato,5,veg
13,cherry,5,fruit

读取文件并通过键创建字典ID
- read_csv:
path: /tmp/fruits.csv
key: id
register: fruits

给
fruits.dict:
'1': {id: '1', name: apple, quantity: '10', type: fruit}
'10': {id: '10', name: guava, quantity: '4', type: fruit}
'11': {id: '11', name: pepper, quantity: '4', type: veg}
'12': {id: '12', name: potato, quantity: '5', type: veg}
'13': {id: '13', name: cherry, quantity: '5', type: fruit}
'2': {id: '2', name: orange, quantity: '20', type: fruit}
'3': {id: '3', name: carrot, quantity: '5', type: veg}
'4': {id: '4', name: beetroot, quantity: '2', type: veg}
'5': {id: '5', name: onion, quantity: '3', type: veg}
'6': {id: '6', name: tomato, quantity: '4', type: both}
'7': {id: '7', name: pear, quantity: '4', type: fruit}
'8': {id: '8', name: banana, quantity: '6', type: fruit}
'9': {id: '9', name: persimon, quantity: '4', type: fruit}}

获取值并将它们分组类型

  by_type: "{{ fruits.dict.values()|groupby('type') }}"

给

  by_type:
    - - both
      - - {id: '6', name: tomato, quantity: '4', type: both}
    - - fruit
      - - {id: '1', name: apple, quantity: '10', type: fruit}
        - {id: '2', name: orange, quantity: '20', type: fruit}
        - {id: '7', name: pear, quantity: '4', type: fruit}
        - {id: '8', name: banana, quantity: '6', type: fruit}
        - {id: '9', name: persimon, quantity: '4', type: fruit}
        - {id: '10', name: guava, quantity: '4', type: fruit}
        - {id: '13', name: cherry, quantity: '5', type: fruit}
    - - veg
      - - {id: '3', name: carrot, quantity: '5', type: veg}
        - {id: '4', name: beetroot, quantity: '2', type: veg}
        - {id: '5', name: onion, quantity: '3', type: veg}
        - {id: '11', name: pepper, quantity: '4', type: veg}
        - {id: '12', name: potato, quantity: '5', type: veg}

创建字典

  my_dict: "{{ dict(by_type|map('first')|list|
                    zip(by_type|map('last')|
                                map('map', attribute='name')|list)) }}"

给

  my_dict:
    both: [tomato]
    fruit: [apple, orange, pear, banana, persimon, guava, cherry]
    veg: [carrot, beetroot, onion, pepper, potato]

创建项目的批次。在哪里类型和输入范围是参数

    my_list: |
      {% for batch in my_dict[type]|batch(input_range|int) %}
        - {{ batch }}
      {% endfor %}

例如下面的循环

    - debug:
        msg: "{{ my_list }}"
      loop: "{{ my_dict.keys()|list }}"
      vars:
        type: "{{ item }}"

对于input_range=2 给出

TASK [debug] **************************************************************
ok: [localhost] => (item=both) => 
  msg: |2-
      - ['tomato']
ok: [localhost] => (item=fruit) => 
  msg: |2-
      - ['apple', 'orange']
      - ['pear', 'banana']
      - ['persimon', 'guava']
      - ['cherry']
ok: [localhost] => (item=veg) => 
  msg: |2-
      - ['carrot', 'beetroot']
      - ['onion', 'pepper']
      - ['potato']

对于input_range=3 给出

TASK [debug] **************************************************************
ok: [localhost] => (item=both) => 
  msg: |2-
      - ['tomato']
ok: [localhost] => (item=fruit) => 
  msg: |2-
      - ['apple', 'orange', 'pear']
      - ['banana', 'persimon', 'guava']
      - ['cherry']
ok: [localhost] => (item=veg) => 
  msg: |2-
      - ['carrot', 'beetroot', 'onion']
      - ['pepper', 'potato']

创建特定列表

    - set_fact:
        my_list_veg: "{{ my_list }}"
      vars:
        type: veg
        input_range: 3
    - debug:
        var: my_list_veg

给

  my_list_veg:
      - ['carrot', 'beetroot', 'onion']
      - ['pepper', 'potato']

^{用于测试的完整剧本示例
shell> cat pb.yml
- hosts: localhost
vars:
input_range: 2
by_type: "{{ fruits.dict.values()|groupby('type') }}"
my_dict: "{{ dict(by_type|map('first')|list|
zip(by_type|map('last')|
map('map', attribute='name')|list)) }}"
my_list: |
{% for batch in my_dict[type]|batch(input_range|int) %}
- {{ batch }}
{% endfor %}

tasks:
- read_csv:
path: /tmp/fruits.csv
key: id
register: fruits
- debug:
var: fruits.dict|to_yaml
- debug:
var: by_type|to_yaml
- debug:
var: my_dict|to_yaml

- debug:
msg: "{{ my_list }}"
loop: "{{ my_dict.keys()|list }}"
vars:
type: "{{ item }}"

- set_fact:
my_list_veg: "{{ my_list }}"
vars:
type: veg
input_range: 3
- debug:
var: my_list_veg

你可以覆盖输入范围从命令行，例如
shell> ansible-playbook pb.yml -e input_range=3}

【讨论】：