join multiple arrays in complex data structure with jmespath - ansible

Question

I'm trying to transform NFS exports, described in complex data structure, to config option accepted by nfs-server daemon which later be used in ansible.
I have:
nfs_exports:
- path: /export/home
state: present
options:
- clients: "192.168.0.0/24"
permissions:
- "rw"
- "sync"
- "no_root_squash"
- "fsid=0"
- path: /export/public
state: present
options:
- clients: "192.168.0.0/24"
permissions:
- "rw"
- "sync"
- "root_squash"
- "fsid=0"
- clients: "*"
permissions:
- "ro"
- "async"
- "all_squash"
- "fsid=1"
which must become:
[
{
"options": "192.168.0.0/24(rw,sync,no_root_squash,fsid=0)",
"path": "/export/home",
"state": "present"
},
{
"options": "192.168.0.0/24(rw,sync,root_squash,fsid=0) *(ro,async,all_squash,fsid=1)",
"path": "/export/public",
"state": "present"
}
]
So far I was able, using {{ nfs_exports | json_query(query) }}
query: "[].{path:path,state:state,options:options.join(` `,[].join(``,[clients,`(`,join(`,`,permissions),`)`]))}"
get
{
"options": "192.168.0.0/24(rw,sync,no_root_squash,fsid=0)",
"path": "/export/home",
"state": "present"
},
{
"options": "192.168.0.0/24(rw,sync,root_squash,fsid=0)*(ro,async,all_squash,fsid=1)",
"path": "/export/public",
"state": "present"
}
It's probably simple but I can't get pass that last options join, space ' ' gets removed.
So if someone knows the correct query additional explanation will be much appreciated.

Answer 1

Given the query:
[].{ path: path, state: state, options: join(' ', options[].join('', [clients, '(', join(',', permissions), ')'])) }
On the JSON
{
"nfs_exports": [
{
"path": "/export/home",
"state": "present",
"options": [
{
"clients": "192.168.0.0/24",
"permissions": [
"rw",
"sync",
"no_root_squash",
"fsid=0"
]
}
]
},
{
"path": "/export/public",
"state": "present",
"options": [
{
"clients": "192.168.0.0/24",
"permissions": [
"rw",
"sync",
"root_squash",
"fsid=0"
]
},
{
"clients": "*",
"permissions": [
"ro",
"async",
"all_squash",
"fsid=1"
]
}
]
}
]
}
It would give you your expected output:
[
{
"path": "/export/home",
"state": "present",
"options": "192.168.0.0/24(rw,sync,no_root_squash,fsid=0)"
},
{
"path": "/export/public",
"state": "present",
"options": "192.168.0.0/24(rw,sync,root_squash,fsid=0) *(ro,async,all_squash,fsid=1)"
}
]
Please mind: the string litteral `` wont work on a space character string, because, as pointed in the documentation, it will be parsed as JSON:
A literal expression is an expression that allows arbitrary JSON objects to be specified
Source: https://jmespath.org/specification.html#literal-expressions
This is quite easy when you get to the point of:
[].{ path: path, state: state, options: options[].join('', [clients, '(', join(',', permissions), ')']) }
Which is something you seems to have achived, that gives
[
{
"path": "/export/home",
"state": "present",
"options": [
"192.168.0.0/24(rw,sync,no_root_squash,fsid=0)"
]
},
{
"path": "/export/public",
"state": "present",
"options": [
"192.168.0.0/24(rw,sync,root_squash,fsid=0)",
"*(ro,async,all_squash,fsid=1)"
]
}
]
Because you are just left with joining the whole array in options with a space as glue character.