PowerShell JSON

json.ps1

$json = '[{
    "certname": "foo.domain.com",
    "environment": "production",
    "name": "keystores",
    "value": {
        "/usr/local/cert/foo.jks:foo": {
            "days_remaining": 396,
            "issuer": "C=COM O=Foo Co. CN=Foo Type 3 CA v1",
            "owner": "C=COM L=Rome O=Vatican CN=pope.domain.com"
        }
    }
},
{
    "certname": "bar.domain.com",
    "environment": "production",
    "name": "keystores",
    "value": {
        "/usr/local/cert/bar.jks:bar": {
            "days_remaining": 396,
            "issuer": "C=COM O=Foo Co. CN=Foo Type 3 CA v1",
            "owner": "C=COM L=Washington D.C. O=White House CN=trump.domain.com"
        },
        "/usr/local/cert/poo.jks:poo": {
            "days_remaining": 396,
            "issuer": "C=COM O=Foo Co. CN=Foo Type 3 CA v1",
            "owner": "C=COM L=London O=Buckingham Palace CN=elizabeth.domain.com"
        }
    }
}]'

foreach ($i in $($json | convertfrom-json).value) { 
    foreach ($n in $($i.psobject.properties).name) {
        [PSCustomObject]@{
            name = $n;
            days_remaining = $i.${n}.days_remaining
        }
    }
}