Ansible - passing JSON string in environment to shell module - json

Question

I am trying to pass JSON string in environment.
- name: Start {{service_name}}
shell: "<<starting springboot jar>> --server.port={{service_port}}\""
environment:
- SPRING_APPLICATION_JSON: '{"test-host.1":"{{test_host_1}}","test-host.2":"{{test_host_2}}"}'
test_host_1 is 172.31.00.00
test_host_2 is 172.31.00.00
But in spring logs, I get JSON parse exception where it prints
Caused by: com.fasterxml.jackson.core.JsonParseException: Unexpected character (''' (code 39)): was expecting double-quote to start field name
at [Source: {'test-host.1': '172.31.00.00', 'test-host.2': '172.31.00.00'}; line: 1, column: 3]
As seen, double quotes are converted to single quotes !!!
I tried escaping double quotes but with no luck.
Any idea why it happens, or any work around?

Answer 1

There is a thing about Ansible template engine.
If a string seems like an object (starts with { or [) Ansible converts it into object. See code.
To prevent this, you may use one of STRING_TYPE_FILTERS:
- SPRING_APPLICATION_JSON: "{{ {'test-host.1':test_host_1,'test-host.2':test_host_2} | to_json }}"
P.S. this is why hack with space character from #techraf's answer works: Ansible misses startswith("{") comparison and don't convert string to object.

Answer 2

Quick hack: add a space to the variable definition (after the first single quote) - a single space doesn't influence the actual variable value (space will be ignored):
- name: Start {{service_name}}
shell: "<<starting springboot jar>> --server.port={{service_port}}\""
environment:
- SPRING_APPLICATION_JSON: ' {"test-host.1":"{{test_host_1}}","test-host.2":"{{test_host_2}}"}'
With the space Ansible passes to shell (test1, test2 are values I set):
SPRING_APPLICATION_JSON='"'"' {"test-host.1":"test1","test-host.2":"test2"}'"'"'
Without the space:
SPRING_APPLICATION_JSON='"'"'{'"'"'"'"'"'"'"'"'test-host.2'"'"'"'"'"'"'"'"': '"'"'"'"'"'"'"'"'test2'"'"'"'"'"'"'"'"', '"'"'"'"'"'"'"'"'test-host.1'"'"'"'"'"'"'"'"': '"'"'"'"'"'"'"'"'test1'"'"'"'"'"'"'"'"'}'"'"'
Order is reversed too. Seems like without a space it interprets the JSON, with the space as string.
I don't really get why it happens so...