NEW PROVIDER: MSDNS (#1005)

* New provider
* Add support for SRV records
* Modify ACTIVEDIRECTORY_PS provider to warn that it is deprecated.

providers/msdns/corrections.go

@@ -0,0 +1,72 @@
+package msdns
+
+import (
+	"fmt"
+
+	"github.com/StackExchange/dnscontrol/v3/models"
+	"github.com/StackExchange/dnscontrol/v3/pkg/diff"
+)
+
+// GetDomainCorrections gets existing records, diffs them against existing, and returns corrections.
+func (c *msdnsProvider) GenerateDomainCorrections(dc *models.DomainConfig, existing models.Records) ([]*models.Correction, error) {
+
+	// Read foundRecords:
+	foundRecords, err := c.GetZoneRecords(dc.Name)
+	if err != nil {
+		return nil, fmt.Errorf("c.GetDNSZoneRecords(%v) failed: %v", dc.Name, err)
+	}
+
+	// Normalize
+	models.PostProcessRecords(foundRecords)
+
+	differ := diff.New(dc)
+	_, creates, dels, modifications, err := differ.IncrementalDiff(foundRecords)
+	if err != nil {
+		return nil, err
+	}
+
+	// Generate changes.
+	corrections := []*models.Correction{}
+	for _, del := range dels {
+		corrections = append(corrections, c.deleteRec(c.dnsserver, dc.Name, del))
+	}
+	for _, cre := range creates {
+		corrections = append(corrections, c.createRec(c.dnsserver, dc.Name, cre)...)
+	}
+	for _, m := range modifications {
+		corrections = append(corrections, c.modifyRec(c.dnsserver, dc.Name, m))
+	}
+	return corrections, nil
+
+}
+
+func (c *msdnsProvider) deleteRec(dnsserver, domainname string, cor diff.Correlation) *models.Correction {
+	rec := cor.Existing
+	return &models.Correction{
+		Msg: cor.String(),
+		F: func() error {
+			return c.shell.RecordDelete(dnsserver, domainname, rec)
+		},
+	}
+}
+
+func (c *msdnsProvider) createRec(dnsserver, domainname string, cre diff.Correlation) []*models.Correction {
+	rec := cre.Desired
+	arr := []*models.Correction{{
+		Msg: cre.String(),
+		F: func() error {
+			return c.shell.RecordCreate(dnsserver, domainname, rec)
+		},
+	}}
+	return arr
+}
+
+func (c *msdnsProvider) modifyRec(dnsserver, domainname string, m diff.Correlation) *models.Correction {
+	old, rec := m.Existing, m.Desired
+	return &models.Correction{
+		Msg: m.String(),
+		F: func() error {
+			return c.shell.RecordModify(dnsserver, domainname, old, rec)
+		},
+	}
+}