输出json对象的个数

Question

我使用Ansible的vmware_cluster_info给出以下json。我需要能够计算集群中的主机数量。群集名称将更改。

                                          {
"ansible_facts": {
"discovered_interpreter_python": "/usr/bin/python"
},
"changed": false,
"clusters": {
"Cluster1": {
"drs_default_vm_behavior": "fullyAutomated",
"ha_restart_priority": [
"medium"
],
"ha_vm_failure_interval": [
50
],
"ha_vm_max_failure_window": [
0
],
"ha_vm_max_failures": [
10
],
"ha_vm_min_up_time": [
90
],
"ha_vm_monitoring": "vmMonitoringOnly",
"ha_vm_tools_monitoring": [
"vmAndAppMonitoring"
],
"hosts": [
{
"folder": "/Datacenter/host/Cluster1",
"name": "host1"
},
{
"folder": "/Datacenter/host/Cluster1",
"name": "host2"
},
{
"folder": "/Datacenter/host/Cluster1",
"name": "host3"
},
{
"folder": "/Datacenter/host/Cluster1",
"name": "host4"
}
],
"resource_summary": {
"cpuCapacityMHz": 144000,
},
"tags": [],
"vsan_auto_claim_storage": false
}
},
"invocation": {
"module_args": {
"cluster_name": "Cluster1",
}
}

}

I have try:

- debug:
msg: "{{ cluster_info.clusters.[].hosts.name | length }}"
- debug:
msg: "{{ cluster_info.clusters.*.hosts.name | length }}"

都给我模板错误，而模板字符串…此外，任何关于教程的建议，等等，学习如何解析json将不胜感激。这对我来说似乎是一个很难的话题。什么好主意吗?

Answer 1

与您尝试的方法类似的一种方法是使用json_query。我理解您想要打印主机的数量，所以您的代码中不需要.name:

- name: print count of hosts
debug:
var: cluster_info.clusters | json_query('*.hosts') | first | length

json_query返回一个列表，这就是为什么我们在length之前将它传递给first。