Ansible 循环
一、简单介绍
在ansible2.5之前，大多数人使”with_XXX”类型的关键字来操作循环，但是从2.6版本开始，官方推荐是”loop”关键字代替” with_XXX”。
1.我们先看下一个小例子，使用loop关键字进行最简单的循环：
[root@localhost cycle]# cat cycle.1.yml --- - name: cycletest hosts: test gather_facts: no tasks: - name: debug cycle debug: msg: "{{ item }}" loop: - test1 - test2
结果：
[root@localhost cycle]# ansible-playbook cycle.1.yml PLAY [cycle test] *************************************************************************************** TASK [debug cycle] ************************************************************************************** ok: [192.168.15.10] => (item=test1) => { "msg": "test1" } ok: [192.168.15.10] => (item=test2) => { "msg": "test2" } PLAY RECAP ********************************************************************************************** 192.168.15.10 : ok=1 changed=0 unreachable=0 failed=0 skipped=0 debug cycle ------------------------------------------------------------- 0.17s Playbook finished: Mon Dec 24 17:57:25 2018, 1 total tasks. 0:00:00 elapsed.
实例中所以loop关键字，替换之前的with_XXX关键字，它们的效果是完全相同的。
2.我们可以使用loop关键字和dict插件代替”with_dict”关键字，示例如下：
[root@localhost cycle]# cat cycle.2.yml --- - name: cycle test2 hosts: test gather_facts: no vars: dicts: China: 1 America: 2 tasks: - name: debug cycle debug: msg: "{{ item.key }} is no.{{ item.value }}" loop: "{{ lookup('dict',dicts) }}"
结果：
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[root@localhost cycle]# ansible-playbook cycle.2.yml PLAY [cycle test2] ************************************************************************************** TASK [debug cycle] ************************************************************************************** ok: [192.168.15.10] => (item={'key': u'America', 'value': 2}) => { "msg": "America is no.2" } ok: [192.168.15.10] => (item={'key': u'China', 'value': 1}) => { "msg": "China is no.1" } PLAY RECAP ********************************************************************************************** 192.168.15.10 : ok=1 changed=0 unreachable=0 failed=0 skipped=0 debug cycle ------------------------------------------------------------- 0.18s Playbook finished: Mon Dec 24 17:59:58 2018, 1 total tasks. 0:00:00 elapsed
示例已经在上一个例子中讲述，再次不在讲述
3.上个例子中使用”loop+lookup”的方式完成循环，而在2.6版本的官网中推荐使用”loop+filter”方式老代替”loop+loopup”的方式，什么意思呢? 我们来看个小例子，如下:
--- - name: cycle test3 hosts: test gather_facts: no vars: dicts: China: 1 America: 2 tasks: - name: debug cycle debug: msg: "{{ item.key }} is no.{{ item.value }}" loop: "{{ dicts | dict2items }}"
结果：
[root@localhost cycle]# ansible-playbook cycle.3.yml PLAY [cycle test3] ************************************************************************************** TASK [debug cycle] ************************************************************************************** ok: [192.168.15.10] => (item={'key': u'America', 'value': 2}) => { "msg": "America is no.2" } ok: [192.168.15.10] => (item={'key': u'China', 'value': 1}) => { "msg": "China is no.1" } PLAY RECAP ********************************************************************************************** 192.168.15.10 : ok=1 changed=0 unreachable=0 failed=0 skipped=0 debug cycle ------------------------------------------------------------- 0.18s Playbook finished: Mon Dec 24 18:05:21 2018, 1 total tasks. 0:00:00 elapsed.
如上例所示，在使用loop关键字操作对于的字典变量users时，并没有借助dict插件，而是使用dict2items的过滤器。
二、具体示例
1.With_list
#loop可以替代with_list，当处理嵌套的列表时，列表不会被拉平
[root@localhost cycle]# cat cycle.4.yml --- - name: cycle test4 hosts: test gather_facts: no vars: dicts: - A - B - [c,D] tasks: - name: debug cycle debug: msg: "{{ item }}" loop: "{{ dicts }}"
结果：
[root@localhost cycle]# ansible-playbook cycle.4.yml
PLAY [cycle test4] **************************************************************************************
TASK [debug cycle] **************************************************************************************
ok: [192.168.15.10] => (item=A) => {
"msg": "A"
}
ok: [192.168.15.10] => (item=B) => {
"msg": "B"
}
ok: [192.168.15.10] => (item=[u'c', u'D']) => {
"msg": [
"c",
"D"
]
}
PLAY RECAP **********************************************************************************************
192.168.15.10 : ok=1 changed=0 unreachable=0 failed=0 skipped=0
debug cycle ------------------------------------------------------------- 0.19s
Playbook finished: Mon Dec 24 18:25:41 2018, 1 total tasks. 0:00:00 elapsed.
2.With_flattened
#flatten过滤器可以替代with_flattened，当处理多层嵌套的列表时，列表中所有的嵌套层级都会被拉平
[root@localhost cycle]# cat cycle.5.yml
---
- name: cycle test5
hosts: test
gather_facts: no
vars:
dicts:
- A
- B
- [c,D]
tasks:
- name: debug cycle
debug:
msg: "{{ item }}"
loop: "{{ dicts | flatten }}"
结果：
[root@localhost cycle]# ansible-playbook cycle.5.yml PLAY [cycle test5] ************************************************************************************** TASK [debug cycle] ************************************************************************************** ok: [192.168.15.10] => (item=A) => { "msg": "A" } ok: [192.168.15.10] => (item=B) => { "msg": "B" } ok: [192.168.15.10] => (item=c) => { "msg": "c" } ok: [192.168.15.10] => (item=D) => { "msg": "D" } PLAY RECAP ********************************************************************************************** 192.168.15.10 : ok=1 changed=0 unreachable=0 failed=0 skipped=0 debug cycle ------------------------------------------------------------- 0.19s Playbook finished: Mon Dec 24 18:31:47 2018, 1 total tasks. 0:00:00 elapsed.
3.With_items
#flatten过滤器（加参数）可以替代with_items，当处理多层嵌套的列表时，只有列表中的第一层会被拉平
[root@localhost cycle]# cat cycle.6.yml --- - name: cycle test6 hosts: test gather_facts: no vars: dicts: - A - B - [c,D] tasks: - name: debug cycle debug: msg: "{{ item }}" loop: "{{ dicts | flatten(levels=1) }}"
结果：
[root@localhost cycle]# ansible-playbook cycle.6.yml PLAY [cycle test6] ************************************************************************************** TASK [debug cycle] ************************************************************************************** ok: [192.168.15.10] => (item=A) => { "msg": "A" } ok: [192.168.15.10] => (item=B) => { "msg": "B" } ok: [192.168.15.10] => (item=c) => { "msg": "c" } ok: [192.168.15.10] => (item=D) => { "msg": "D" } PLAY RECAP ********************************************************************************************** 192.168.15.10 : ok=1 changed=0 unreachable=0 failed=0 skipped=0 debug cycle ------------------------------------------------------------- 0.29s Playbook finished: Mon Dec 24 18:34:31 2018, 1 total tasks. 0:00:00 elapsed.
#PS 嗯 处理下客户问题先。Weblogic真毒~
4.With_indexed_items
#flatten过滤器（加参数），再配合loop_control关键字，可以替代with_indexed_items
#当处理多层嵌套的列表时，只有列表中的第一层会被拉平，flatten过滤器的bug暂且忽略
[root@localhost cycle]# cat cycle.7.yml --- - name: cycle test7 hosts: test gather_facts: no vars: dicts: - A - B - [c,D] tasks: - name: debug cycle debug: msg: " {{ index}}--{{ item }}" loop: "{{ dicts | flatten(levels=1) }}" loop_control: index_var: index
结果：
[root@localhost cycle]# ansible-playbook cycle.7.yml PLAY [cycle test7] ************************************************************************************** TASK [debug cycle] ************************************************************************************** ok: [192.168.15.10] => (item=A) => { "msg": " 0--A" } ok: [192.168.15.10] => (item=B) => { "msg": " 1--B" } ok: [192.168.15.10] => (item=c) => { "msg": " 2--c" } ok: [192.168.15.10] => (item=D) => { "msg": " 3--D" } PLAY RECAP ********************************************************************************************** 192.168.15.10 : ok=1 changed=0 unreachable=0 failed=0 skipped=0 debug cycle ------------------------------------------------------------- 0.21s Playbook finished: Mon Dec 24 20:29:57 2018, 1 total tasks. 0:00:00 elapsed.
“loop_control”关键字可以用于控制循环的行为，比如在循环是获取元素的索引。
“index_var “是”loop_control”的一个设置选项，”index_var”可以让我们指定变量,”loop_control”会将元素索引值存放在指定变量中
5.With_togeher
[root@localhost cycle]# cat cycle.8.yml --- - name: cycle test8 hosts: test gather_facts: no vars: testlist1: [ A,B,C,D ] testlist2: [ 110,120,911 ] testlist3: [ x,y ] tasks: - name: debug cycle with_together debug: msg: " {{ item.0 }} - {{ item.1 }} - {{ item.2 }}" with_together: - "{{ testlist1 }}" - "{{ testlist2 }}" - "{{ testlist3 }}" - name: debug cycle loop+zip_logest debug: msg: " {{ item.0 }} - {{ item.1 }} - {{ item.2 }}" loop: "{{ testlist1 | zip_longest(testlist2,testlist3) | list }}
结果：
[root@localhost cycle]# ansible-playbook cycle.8.yml PLAY [cycle test8] ************************************************************************************** TASK [debug cycle with_together] ************************************************************************ ok: [192.168.15.10] => (item=[u'A', 110, u'x']) => { "msg": " A - 110 - x" } ok: [192.168.15.10] => (item=[u'B', 120, u'y']) => { "msg": " B - 120 - y" } ok: [192.168.15.10] => (item=[u'C', 911, None]) => { "msg": " C - 911 - " } ok: [192.168.15.10] => (item=[u'D', None, None]) => { "msg": " D - - " } TASK [debug cycle loop+zip_logest] ********************************************************************** ok: [192.168.15.10] => (item=[u'A', 110, u'x']) => { "msg": " A - 110 - x" } ok: [192.168.15.10] => (item=[u'B', 120, u'y']) => { "msg": " B - 120 - y" } ok: [192.168.15.10] => (item=[u'C', 911, None]) => { "msg": " C - 911 - " } ok: [192.168.15.10] => (item=[u'D', None, None]) => { "msg": " D - - " } PLAY RECAP ********************************************************************************************** 192.168.15.10 : ok=2 changed=0 unreachable=0 failed=0 skipped=0 debug cycle with_together ----------------------------------------------- 0.25s debug cycle loop+zip_logest --------------------------------------------- 0.21s Playbook finished: Mon Dec 24 20:44:42 2018, 2 total tasks. 0:00:00 elapsed.
示例中同时写出2中方法方便进行比较。
但多个列表使用”with_together”进行对比合并时，如果列表长度不同，这使用最长的列表长度进行对其，由于短列表中元素不足，所以使用空值与长列表中元素进行对齐，zip_longest过滤器也和”with_together”一样，对列表进行组合，但是还需要借助list过滤器，将组合的数据列表化。
可以指定字符代替空值
- debug: msg: "{{ item.0 }} - {{ item.1 }} - {{item.2}}" loop: "{{ testlist1 | zip_longest(testlist2,testlist3,fillvalue='None') | list }}" 和最短的列表进行对齐 - debug: msg: "{{ item.0 }} - {{ item.1 }} - {{item.2}}" loop: "{{ testlist1 | zip(testlist2,testlist3) | list }}" 6.With_nested/With_cartesian #product过滤器配合list过滤器，可以替代with_nested和with_cartesian [root@localhost cycle]# cat cycle.9.yml --- - name: cycle test4 hosts: test gather_facts: no vars: list1: [ 1,2,3 ] list2: [ a,b,c,d ] tasks: - name: debug cycle debug: msg: "{{ item.0 }} ---- {{ item.1 }}" loop: "{{ list1 | product(list2) | list }}"
结果：
[root@localhost cycle]# ansible-playbook cycle.9.yml PLAY [cycle test4] ************************************************************************************** TASK [debug cycle] ************************************************************************************** ok: [192.168.15.10] => (item=[1, u'a']) => { "msg": "1 ---- a" } ok: [192.168.15.10] => (item=[1, u'b']) => { "msg": "1 ---- b" } ok: [192.168.15.10] => (item=[1, u'c']) => { "msg": "1 ---- c" } ok: [192.168.15.10] => (item=[1, u'd']) => { "msg": "1 ---- d" } ok: [192.168.15.10] => (item=[2, u'a']) => { "msg": "2 ---- a" } ok: [192.168.15.10] => (item=[2, u'b']) => { "msg": "2 ---- b" } ok: [192.168.15.10] => (item=[2, u'c']) => { "msg": "2 ---- c" } ok: [192.168.15.10] => (item=[2, u'd']) => { "msg": "2 ---- d" } ok: [192.168.15.10] => (item=[3, u'a']) => { "msg": "3 ---- a" } ok: [192.168.15.10] => (item=[3, u'b']) => { "msg": "3 ---- b" } ok: [192.168.15.10] => (item=[3, u'c']) => { "msg": "3 ---- c" } ok: [192.168.15.10] => (item=[3, u'd']) => { "msg": "3 ---- d" } PLAY RECAP ********************************************************************************************** 192.168.15.10 : ok=1 changed=0 unreachable=0 failed=0 skipped=0 debug cycle ------------------------------------------------------------- 0.31s Playbook finished: Mon Dec 24 20:55:19 2018, 1 total tasks. 0:00:00 elapsed.
7.With_random_choice
#使用random函数可以替代with_random_choice，由于random函数是随机取出列表中的一个值，并不涉及循环操作，所以并不用使用loop关键字。
[root@localhost cycle]# cat cycle.10.yml --- - name: cycle test hosts: test gather_facts: no vars: list: [a,b,c] tasks: - name: debug cycle debug: msg: "{{ list | random }}" - debug: msg: "{{ list | random }}" - debug: msg: "{{ list | random }}
结果：
[root@localhost cycle]# ansible-playbook cycle.10.yml PLAY [cycle test] *************************************************************************************** TASK [debug cycle] ************************************************************************************** ok: [192.168.15.10] => { "msg": "a" } TASK [debug] ******************************************************************************************** ok: [192.168.15.10] => { "msg": "a" } TASK [debug] ******************************************************************************************** ok: [192.168.15.10] => { "msg": "c" } PLAY RECAP ********************************************************************************************** 192.168.15.10 : ok=3 changed=0 unreachable=0 failed=0 skipped=0 debug cycle ------------------------------------------------------------- 0.18s ------------------------------------------------------------------------ 0.16s Playbook finished: Mon Dec 24 21:06:32 2018, 2 total tasks. 0:00:00 elapsed.
8.with_dict
#除了上文总结的dict2items过滤器，dictsort过滤器也可以替代with_dict
[root@localhost cycle]# cat cycle.11.yml --- - name: cycle test2 hosts: test gather_facts: no vars: dicts: China: 1 America: 2 aaa: 3 bbb: 4 ccc: 5 tasks: - name: debug cycle dict2items debug: msg: "{{ item.key }} is no.{{ item.value }}" loop: "{{ dicts | dict2items }}" - name: debug cycle debug: msg: "{{ item.0 }} is no.{{ item.1 }}" loop: "{{ dicts | dictsort }}"
结果：
[root@localhost cycle]# ansible-playbook cycle.11.yml PLAY [cycle test2] ************************************************************************************** TASK [debug cycle dict2items] *************************************************************************** ok: [192.168.15.10] => (item={'key': u'China', 'value': 1}) => { "msg": "China is no.1" } ok: [192.168.15.10] => (item={'key': u'America', 'value': 2}) => { "msg": "America is no.2" } ok: [192.168.15.10] => (item={'key': u'aaa', 'value': 3}) => { "msg": "aaa is no.3" } ok: [192.168.15.10] => (item={'key': u'bbb', 'value': 4}) => { "msg": "bbb is no.4" } ok: [192.168.15.10] => (item={'key': u'ccc', 'value': 5}) => { "msg": "ccc is no.5" } TASK [debug cycle] ************************************************************************************** ok: [192.168.15.10] => (item=[u'aaa', 3]) => { "msg": "aaa is no.3" } ok: [192.168.15.10] => (item=[u'America', 2]) => { "msg": "America is no.2" } ok: [192.168.15.10] => (item=[u'bbb', 4]) => { "msg": "bbb is no.4" } ok: [192.168.15.10] => (item=[u'ccc', 5]) => { "msg": "ccc is no.5" } ok: [192.168.15.10] => (item=[u'China', 1]) => { "msg": "China is no.1" } PLAY RECAP ********************************************************************************************** 192.168.15.10 : ok=2 changed=0 unreachable=0 failed=0 skipped=0 debug cycle dict2items -------------------------------------------------- 0.26s debug cycle ------------------------------------------------------------- 0.22s Playbook finished: Mon Dec 24 21:10:40 2018, 2 total tasks. 0:00:00 elapsed.