Unmarshaling nested xml golang

I want to unmarshall a nested xml to a golang struct. The xml that I want to unmarshall is shown below.

<?xml version="1.0" encoding="UTF-8"?>
<status>
	<authorized>true</authorized>
	<plan>Basic</plan>
	<usage_reports>
		<usage_report metric="hits" period="day">
			<period_start>2021-07-20 00:00:00 +0000</period_start>
			<period_end>2021-07-21 00:00:00 +0000</period_end>
			<max_value>1000000</max_value>
			<current_value>0</current_value>
		</usage_report>
		<usage_report metric="hits.82343" period="day">
			<period_start>2021-07-20 00:00:00 +0000</period_start>
			<period_end>2021-07-21 00:00:00 +0000</period_end>
			<max_value>1000000</max_value>
			<current_value>0</current_value>
		</usage_report>
	</usage_reports>
</status>

To unmarshall I have defined two go structs as follows.

// UsageReport represents the usage report of a particular metric.
type UsageReport struct {
	Usage   string `xml:"usage_report,chardata"`
	Metric  string `xml:"metric,attr"`
	Period  string `xml:"period,attr"`
	Start   string `xml:"period_start"`
	End     string `xml:"period_end"`
	Max     int64  `xml:"max_value"`
	Current int64  `xml:"current_value"`
}

// AuthResponse represents the structure of the response from authorize calls.
type AuthResponse struct {
	Status     xml.Name      `xml:"status"`
	Authorized bool          `xml:"authorized"`
	Plan       string        `xml:"plan"`
	Usages     []UsageReport `xml:"usage_reports"`
}

But when I try to unmarshall using xml.Unmarshal, only Plan and Authorized values gets unmarshalled. The result of unmarshalling is shown below.

XML: {{ } true Basic []}

Try this go playground. I use this tool to cheat and help me generate Go types from XML data.

package main

import (
	"encoding/xml"
	"fmt"
)

type Status struct {
	XMLName      xml.Name `xml:"status"`
	Text         string   `xml:",chardata"`
	Authorized   string   `xml:"authorized"`
	Plan         string   `xml:"plan"`
	UsageReports struct {
		Text        string `xml:",chardata"`
		UsageReport []struct {
			Text         string `xml:",chardata"`
			Metric       string `xml:"metric,attr"`
			Period       string `xml:"period,attr"`
			PeriodStart  string `xml:"period_start"`
			PeriodEnd    string `xml:"period_end"`
			MaxValue     string `xml:"max_value"`
			CurrentValue string `xml:"current_value"`
		} `xml:"usage_report"`
	} `xml:"usage_reports"`
}

func main() {
	status := Status{}
	err := xml.Unmarshal([]byte(xmlStr), &status)
	if err != nil {
		panic(err)
	}
	fmt.Println(status.UsageReports.UsageReport[0].MaxValue)
}

const xmlStr = `<?xml version="1.0" encoding="UTF-8"?><status><authorized>true</authorized><plan>Basic</plan><usage_reports><usage_report metric="hits" period="day"><period_start>2021-07-20 00:00:00 +0000</period_start><period_end>2021-07-21 00:00:00 +0000</period_end><max_value>1000000</max_value><current_value>0</current_value></usage_report><usage_report metric="hits.82343" period="day"><period_start>2021-07-20 00:00:00 +0000</period_start><period_end>2021-07-21 00:00:00 +0000</period_end><max_value>1000000</max_value><current_value>0</current_value></usage_report></usage_reports></status>`

In order to get the value of Usages field modify xml:"usage_reports" to xml:"usage_reports>usage_report" as per the suggestions of mkopriva.

package main

import (
	"encoding/xml"
	"fmt"
)

type UsageReport struct {
	Metric  string `xml:"metric,attr"`
	Period  string `xml:"period,attr"`
	Start   string `xml:"period_start"`
	End     string `xml:"period_end"`
	Max     int64  `xml:"max_value"`
	Current int64  `xml:"current_value"`
}

type AuthResponse struct {
	Status     xml.Name      `xml:"status"`
	Authorized bool          `xml:"authorized"`
	Plan       string        `xml:"plan"`
	Usages     []UsageReport `xml:"usage_reports>usage_report"`
}

var data = []byte(`<?xml version="1.0" encoding="UTF-8"?>
<status>
    <authorized>true</authorized>
    <plan>Basic</plan>
    <usage_reports>
        <usage_report metric="hits" period="day">
            <period_start>2021-07-20 00:00:00 +0000</period_start>
            <period_end>2021-07-21 00:00:00 +0000</period_end>
            <max_value>1000000</max_value>
            <current_value>0</current_value>
        </usage_report>
        <usage_report metric="hits.82343" period="day">
            <period_start>2021-07-20 00:00:00 +0000</period_start>
            <period_end>2021-07-21 00:00:00 +0000</period_end>
            <max_value>1000000</max_value>
            <current_value>0</current_value>
        </usage_report>
    </usage_reports>
</status>
`)

func main() {
	r := AuthResponse{}
	if err := xml.Unmarshal(data, &r); err != nil {
		panic(err)
	}
	fmt.Println(r)
}

Output:

{{ } true Basic [{hits day 2021-07-20 00:00:00 +0000 2021-07-21 00:00:00 +0000 1000000 0} {hits.82343 day 2021-07-20 00:00:00 +0000 2021-07-21 00:00:00 +0000 1000000 0}]}