86 lines
2.0 KiB
Go
86 lines
2.0 KiB
Go
package core
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import (
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"errors"
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"fmt"
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"strings"
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"github.com/miekg/dns"
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)
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var (
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// ErrDNSWithNoQueryName is the error with which gatus will panic if a dns is configured without query name
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ErrDNSWithNoQueryName = errors.New("you must specify a query name for DNS")
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// ErrDNSWithInvalidQueryType is the error with which gatus will panic if a dns is configured with invalid query type
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ErrDNSWithInvalidQueryType = errors.New("invalid query type")
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)
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const (
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dnsPort = 53
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)
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// DNS is the configuration for a Service of type DNS
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type DNS struct {
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// QueryType is the type for the DNS records like A, AAAA, CNAME...
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QueryType string `yaml:"query-type"`
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// QueryName is the query for DNS
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QueryName string `yaml:"query-name"`
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}
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func (d *DNS) validateAndSetDefault() {
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if len(d.QueryName) == 0 {
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panic(ErrDNSWithNoQueryName)
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}
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if !strings.HasSuffix(d.QueryName, ".") {
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d.QueryName += "."
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}
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if _, ok := dns.StringToType[d.QueryType]; !ok {
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panic(ErrDNSWithInvalidQueryType)
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}
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}
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func (d *DNS) query(url string, result *Result) {
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if !strings.Contains(url, ":") {
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url = fmt.Sprintf("%s:%d", url, dnsPort)
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}
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queryType := dns.StringToType[d.QueryType]
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c := new(dns.Client)
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m := new(dns.Msg)
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m.SetQuestion(d.QueryName, queryType)
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r, _, err := c.Exchange(m, url)
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if err != nil {
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result.Errors = append(result.Errors, err.Error())
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return
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}
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result.Connected = true
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result.DNSRCode = dns.RcodeToString[r.Rcode]
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for _, rr := range r.Answer {
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switch rr.Header().Rrtype {
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case dns.TypeA:
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if a, ok := rr.(*dns.A); ok {
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result.Body = []byte(a.A.String())
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}
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case dns.TypeAAAA:
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if aaaa, ok := rr.(*dns.AAAA); ok {
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result.Body = []byte(aaaa.AAAA.String())
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}
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case dns.TypeCNAME:
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if cname, ok := rr.(*dns.CNAME); ok {
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result.Body = []byte(cname.Target)
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}
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case dns.TypeMX:
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if mx, ok := rr.(*dns.MX); ok {
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result.Body = []byte(mx.Mx)
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}
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case dns.TypeNS:
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if ns, ok := rr.(*dns.NS); ok {
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result.Body = []byte(ns.Ns)
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}
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default:
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result.Body = []byte("query type is not supported yet")
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}
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}
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}
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