Multiple json_query in Ansible? - ansible

Question

I have the following yaml file.
resources:
- apiVersion: v1
kind: Deployment
metadata:
labels:
app: test
name: test-cluster-operator
namespace: destiny001
spec:
selector:
matchLabels:
name: test-cluster-operator
test.io/kind: cluster-operator
strategy:
type: Recreate
template:
metadata:
labels:
name: test-cluster-operator
test.io/kind: cluster-operator
spec:
containers:
- args:
- /path/test/bin/cluster_operator_run.sh
env:
- name: MY_NAMESPACE
valueFrom:
fieldRef:
apiVersion: v1
fieldPath: metadata.namespace
imagePullPolicy: IfNotPresent
livenessProbe:
failureThreshold: 3
httpGet:
path: /healthy
port: 8080
scheme: HTTP
initialDelaySeconds: 10
periodSeconds: 30
successThreshold: 1
timeoutSeconds: 1
name: test-cluster-operator
readinessProbe:
failureThreshold: 3
httpGet:
path: /ready
port: 8080
scheme: HTTP
initialDelaySeconds: 10
periodSeconds: 30
successThreshold: 1
timeoutSeconds: 1
resources:
limits:
cpu: '1'
memory: 256Mi
requests:
cpu: 200m
memory: 256Mi
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
volumeMounts:
- mountPath: /var/data
name: data-cluster-operator
dnsPolicy: ClusterFirst
restartPolicy: Always
schedulerName: default-scheduler
securityContext: {}
serviceAccount: test-cluster-operator
serviceAccountName: test-cluster-operator
terminationGracePeriodSeconds: 30
volumes:
- name: data-cluster-operator
persistentVolumeClaim:
claimName: data-cluster-operator
I am trying to get the the value of env variable called MY_NAMESPACE.
This is what I tried in Ansible to get to the env tree path.
- name: "set test fact"
set_fact:
myresult: "{{ yaml_file_variable | json_query(\"resources[?metadata.name=='test-cluster-operator'].spec.template.spec\") | json_query(\"containers[?name=='test-cluster-operator'].env\") }}"
- name: "debug"
debug:
msg: "{{ myresult }}"
This produces an empty list, however the first json_query works well.
How do I use json_query correctly in this case?
Can I achieve this with just one json_query?
EDIT:
I seem to be closer to a solution but the result ist a list and not string, which I find annoying.
- name: "set test fact"
set_fact:
myresult: "{{ yaml_file_variable | json_query(\"resources[?metadata.name=='test-cluster-operator'].spec.template.spec\") | json_query(\"[].containers[?name=='test-cluster-operator']\") | json_query(\"[].env[?name=='MY_NAMESPACE'].name\") }}"
This prints - - MY_NAMESPACE instead of just MY_NAMESPACE.
Do I have to use first filter every time after json_query? I know for sure that there is only one containers element. I don't understand why json_query returns a list.
This is finally working but no idea whether it's correct way to do it.
- name: "set test fact"
set_fact:
myresult: "{{ yaml_file_variable | json_query(\"resources[?metadata.name=='test-cluster-operator'].spec.template.spec\") | first | json_query(\"containers[?name=='test-cluster-operator']\") | first | json_query(\"env[?name=='MY_NAMESPACE'].valueFrom \") | first }}"

Answer 1

json_query uses jmespath and jmespath always returns a list. This is why your first example isn't working. The first query returns a list but the second is trying to query a key. You've corrected that in the second with [].
You're also missing the jmespath pipe expression: | which is used pretty much as you might expect - the result of the first query can be piped into a new one. Note that this is separate from ansible filters using the same character.
This query:
resources[?metadata.name=='test-cluster-operator'].spec.template.spec | [].containers[?name=='test-cluster-operator'][].env[].valueFrom
Should give you the following output:
[
{
"fieldRef": {
"apiVersion": "v1",
"fieldPath": "metadata.namespace"
}
}
]
Your task should look like this:
- name: "set test fact"
set_fact:
myresult: "{{ yaml_file_variable | json_query(\"resources[?metadata.name=='test-cluster-operator'].spec.template.spec | [].containers[?name=='test-cluster-operator'][].env[].valueFrom\") | first }}"
To answer your other question, yes you'll need to the first filter. As mentioned jmespath will always return a list, so if you just want the value of a key you'll need to pull it out.