if key exist,then replace value ,if not exist ,do not create key

[pycgo]

[root@test ~]# yq e test.yaml 
spring:
  dataSource:
    username: zxx
    password: 123456
    url: jdbc:mysql://test.bd.com:3306
if key exist,then replace value  that is ok 

[root@test ~]# yq e '.spring.dataSource.username="aaa"' test.yaml
spring:
dataSource:
username: aaa
password: 123456
url: jdbc:mysql://test.bd.com:3306

but i want first judge the key "uername111" is exist in orign file ,then repalce it ；if not exist，then do not create new key "username111"

[root@test ~]# yq e '.spring.dataSource.username111="aaa"' test.yaml
spring:
dataSource:
username: zxx
password: 123456
url: jdbc:mysql://test.bd.com:3306
username111: aaa
[root@test ~]#

[pycgo]

how can i judge the key "uername111" is exist? then replace?

[pycgo]

if yq e '.spring[] | has "username"' test.yaml;then yq -i e '.spring.dataSource.username="fffff"' test.yaml ; fi

this way is too complex ,there is a simple way can do it ??

[mikefarah]

I'm getting a little confused with your examples, because they are formatted poorly. I think what you need is something like this:

yq e '(.spring.dataSource | select(has("username")) | .username) = "fred"' examples/data1.yaml

[mikefarah]

The key bit is the select, if spring.dataSource does not have that key, then the context piped into '.username' will be empty...

[pycgo]

oh thankyou i just need it . great!!!

[mueslo]

@mikefarah At least in yq 4 this is not quite correct.

If I use your proposed command, then it will set ".spring.dataSource" to "null" if it doesn't yet exist. IMO the correct way would be

yq e 'select(.spring.dataSource.username) | .spring.dataSource.username = "fred"' examples/data1.yaml

and if you want to use the exit code for whether the field exists:

yq e 'select(.spring.dataSource.username) | .spring.dataSource.username = "fred"' -e examples/data1.yaml