Update a value in a list of dictionaries

I have the following list of dictionaries:

"errorlist": [
    {
        "error": "Not found",
        "path": "/tmp/working/directory1/file1"
    },
    {
        "error": "Not found",
        "path": "/tmp/working/directory2/file1"
    },
    {
        "error": "Not found",
        "path": "/tmp/working/directory1/file2"
    },
    {
        "error": "Not found",
        "path": "/tmp/working/directory2/file2"
    }
]

I'd like to remove the "/tmp/working/" part of the path values, i.e. convert the absolute paths to relative ones.

I've been through similar questions while searching online but haven't found a solution. It should be rather simple but I can't wrap my head around it.

The expected result should be either the original list with updated values or a new list with the same structure.

Solution

Filter the basenames and create a list of dictionaries

  paths: "{{ errorlist | map(attribute='path') | map('basename') |
                         map('community.general.dict_kv', 'path') }}"

gives

  paths:
    - {path: file1}
    - {path: file1}
    - {path: file2}
    - {path: file2}

zip the lists and combine the items

  result: "{{ errorlist | zip(paths) | map('combine') }}"

gives

  result:
    - {error: Not found, path: file1}
    - {error: Not found, path: file1}
    - {error: Not found, path: file2}
    - {error: Not found, path: file2}

Fit the pipes to your needs.

^{Example of a complete playbook for testing

- hosts: localhost

vars:

errorlist:
- {error: Not found, path: /tmp/working/directory1/file1}
- {error: Not found, path: /tmp/working/directory2/file1}
- {error: Not found, path: /tmp/working/directory1/file2}
- {error: Not found, path: /tmp/working/directory2/file2}

paths: "{{ errorlist | map(attribute='path') | map('basename') |
map('community.general.dict_kv', 'path') }}"
result: "{{ errorlist | zip(paths) | map('combine') }}"

tasks:

- debug:
var: paths | to_yaml
- debug:
var: result | to_yaml

Fit the filters to your needs. For example, to remove any part of the string use the filter regex_replace

paths: "{{ errorlist | map(attribute='path') |
map('regex_replace', '/tmp/working/(.*)', '\\1') |
map('community.general.dict_kv', 'path') }}"

gives
paths:
- {path: directory1/file1}
- {path: directory2/file1}
- {path: directory1/file2}
- {path: directory2/file2}

This will result in
result:
- {error: Not found, path: directory1/file1}
- {error: Not found, path: directory2/file1}
- {error: Not found, path: directory1/file2}
- {error: Not found, path: directory2/file2}}

Q: "How can I achieve the same result without community.general.dict_kv?"

A: Use json_query. The below declaration gives the same result

  paths: "{{ errorlist | map(attribute='path') |
                         map('regex_replace', '/tmp/working/(.*)', '\\1') |
                         json_query('[].{path: @}') }}"

In Ansible 2.9 and lower try to add the filter list

  paths: "{{ errorlist | map(attribute='path') | list |
                         map('regex_replace', '/tmp/working/(.*)', '\\1') | list |
                         json_query('[].{path: @}') | list }}"

^{Debugging
Decompose the pipe
path1: "{{ errorlist | map(attribute='path') }}"
path2: "{{ errorlist | map(attribute='path') |
map('regex_replace', '/tmp/working/(.*)', '\\1') }}"
path3: "{{ errorlist | map(attribute='path') |
map('regex_replace', '/tmp/working/(.*)', '\\1') |
json_query('[].{path: @}') }}"

and display the types of intermediary results
- debug:
msg: "{{ path1 | type_debug }}"
- debug:
msg: "{{ path2 | type_debug }}"
- debug:
msg: "{{ path3 | type_debug }}"}