refactor: Break core package into multiple packages under config/endpoint (#759)

* refactor: Partially break core package into dns, result and ssh packages

* refactor: Move core package to config/endpoint

* refactor: Fix warning about overlapping imported package name with endpoint variable

* refactor: Rename EndpointStatus to Status

* refactor: Merge result pkg back into endpoint pkg, because it makes more sense

* refactor: Rename parameter r to result in Condition.evaluate

* refactor: Rename parameter r to result

* refactor: Revert accidental change to endpoint.TypeDNS

* refactor: Rename parameter r to result

* refactor: Merge util package into endpoint package

* refactor: Rename parameter r to result

config/endpoint/result.go

@@ -0,0 +1,64 @@
+package endpoint
+
+import (
+	"time"
+)
+
+// Result of the evaluation of a Endpoint
+type Result struct {
+	// HTTPStatus is the HTTP response status code
+	HTTPStatus int `json:"status,omitempty"`
+
+	// DNSRCode is the response code of a DNS query in a human-readable format
+	//
+	// Possible values: NOERROR, FORMERR, SERVFAIL, NXDOMAIN, NOTIMP, REFUSED
+	DNSRCode string `json:"-"`
+
+	// Hostname extracted from Endpoint.URL
+	Hostname string `json:"hostname,omitempty"`
+
+	// IP resolved from the Endpoint URL
+	IP string `json:"-"`
+
+	// Connected whether a connection to the host was established successfully
+	Connected bool `json:"-"`
+
+	// Duration time that the request took
+	Duration time.Duration `json:"duration"`
+
+	// Errors encountered during the evaluation of the Endpoint's health
+	Errors []string `json:"errors,omitempty"`
+
+	// ConditionResults are the results of each of the Endpoint's Condition
+	ConditionResults []*ConditionResult `json:"conditionResults,omitempty"`
+
+	// Success whether the result signifies a success or not
+	Success bool `json:"success"`
+
+	// Timestamp when the request was sent
+	Timestamp time.Time `json:"timestamp"`
+
+	// CertificateExpiration is the duration before the certificate expires
+	CertificateExpiration time.Duration `json:"-"`
+
+	// DomainExpiration is the duration before the domain expires
+	DomainExpiration time.Duration `json:"-"`
+
+	// Body is the response body
+	//
+	// Note that this field is not persisted in the storage.
+	// It is used for health evaluation as well as debugging purposes.
+	Body []byte `json:"-"`
+}
+
+// AddError adds an error to the result's list of errors.
+// It also ensures that there are no duplicates.
+func (r *Result) AddError(error string) {
+	for _, resultError := range r.Errors {
+		if resultError == error {
+			// If the error already exists, don't add it
+			return
+		}
+	}
+	r.Errors = append(r.Errors, error)
+}