Extend configuration validation (#28)

Add configuration validation to report any issues on earlier stages,
right at start actually.

Signed-off-by: Igor Shishkin <me@teran.dev>

config/config.go

@@ -6,10 +6,24 @@ import (
 	"path/filepath"
 	"strings"
 
+	"github.com/asaskevich/govalidator"
+	validation "github.com/go-ozzo/ozzo-validation/v4"
+	"github.com/go-ozzo/ozzo-validation/v4/is"
 	"github.com/pkg/errors"
 	yaml "gopkg.in/yaml.v3"
 )
 
+var isCIDR = validation.NewStringRuleWithError(govalidator.IsCIDR, validation.NewError("validation_is_cidr", "must be a valid CIDR"))
+
+var (
+	_ validation.Validatable = (*Config)(nil)
+	_ validation.Validatable = (*Announcer)(nil)
+	_ validation.Validatable = (*Service)(nil)
+	_ validation.Validatable = (*Metrics)(nil)
+	_ validation.Validatable = (*Check)(nil)
+	_ validation.Validatable = (*Peer)(nil)
+)
+
 type Announcer struct {
 	RouterID     string   `json:"router_id"`
 	LocalAddress string   `json:"local_address"`
@@ -18,35 +32,82 @@ type Announcer struct {
 	Peers        []Peer   `json:"peers"`
 }
 
+func (a Announcer) Validate() error {
+	return validation.ValidateStruct(&a,
+		validation.Field(&a.RouterID, validation.Required, is.IPv4),
+		validation.Field(&a.LocalAddress, validation.Required, is.IPv4),
+		validation.Field(&a.LocalASN, validation.Required),
+		validation.Field(&a.Routes, validation.Required, validation.Each(isCIDR)),
+		validation.Field(&a.Peers, validation.Required),
+	)
+}
+
 type Check struct {
 	Kind string          `json:"kind"`
 	Spec json.RawMessage `json:"spec"`
 }
 
+func (c Check) Validate() error {
+	return validation.ValidateStruct(&c,
+		validation.Field(&c.Kind, validation.Required),
+		validation.Field(&c.Spec, validation.Required),
+	)
+}
+
 type Peer struct {
 	Name          string `json:"name"`
 	RemoteAddress string `json:"remote_address"`
 	RemoteASN     uint32 `json:"remote_asn"`
 }
 
+func (p Peer) Validate() error {
+	return validation.ValidateStruct(&p,
+		validation.Field(&p.Name, validation.Required),
+		validation.Field(&p.RemoteAddress, validation.Required, is.IPv4),
+		validation.Field(&p.RemoteASN, validation.Required),
+	)
+}
+
 type Service struct {
 	Name          string   `json:"name"`
-	CheckOperator string   `json:"check_operator"`
 	CheckInterval Duration `json:"check_interval"`
 	Checks        []Check  `json:"checks"`
 }
 
+func (s Service) Validate() error {
+	return validation.ValidateStruct(&s,
+		validation.Field(&s.Name, validation.Required),
+		validation.Field(&s.CheckInterval, validation.Required),
+		validation.Field(&s.Checks, validation.Required),
+	)
+}
+
 type Metrics struct {
 	Enabled bool   `json:"enabled"`
 	Address string `json:"address"`
 }
 
+func (m Metrics) Validate() error {
+	return validation.ValidateStruct(&m,
+		validation.Field(&m.Enabled, validation.Required),
+		validation.Field(&m.Address, validation.Required),
+	)
+}
+
 type Config struct {
 	Announcer Announcer `json:"announcer"`
 	Services  []Service `json:"services"`
 	Metrics   Metrics   `json:"metrics"`
 }
 
+func (c *Config) Validate() error {
+	return validation.ValidateStruct(c,
+		validation.Field(&c.Announcer, validation.Required),
+		validation.Field(&c.Services, validation.Required),
+		validation.Field(&c.Metrics, validation.Required),
+	)
+}
+
 func NewFromFile(filename string) (*Config, error) {
 	cfg := &Config{}
 
@@ -86,5 +147,5 @@ func NewFromFile(filename string) (*Config, error) {
 		return nil, errors.Wrap(err, "error unmarshaling config")
 	}
 
-	return cfg, nil
+	return cfg, cfg.Validate()
 }

config/config_test.go

@@ -39,7 +39,6 @@ func TestConfig(t *testing.T) {
 		Services: []Service{
 			{
 				Name:          "http",
-				CheckOperator: "and",
 				CheckInterval: Duration(time.Duration(10 * time.Second)),
 				Checks: []Check{
 					{
@@ -92,7 +91,6 @@ func TestConfig(t *testing.T) {
 				for i := range tc.expOut.Services {
 					r.Equalf(tc.expOut.Services[i].Name, cfg.Services[i].Name, "svc#%d", i)
 					r.Equalf(tc.expOut.Services[i].CheckInterval, cfg.Services[i].CheckInterval, "svc#%d", i)
-					r.Equalf(tc.expOut.Services[i].CheckOperator, cfg.Services[i].CheckOperator, "svc#%d", i)
 					for j := range tc.expOut.Services[i].Checks {
 						r.Equalf(tc.expOut.Services[i].Checks[j].Kind, cfg.Services[i].Checks[j].Kind, "svc#%d check#%d", i, j)
 						r.JSONEqf(string(tc.expOut.Services[i].Checks[j].Spec), string(cfg.Services[i].Checks[j].Spec), "svc#%d check#%d", i, j)
@@ -106,3 +104,22 @@ func TestConfig(t *testing.T) {
 		})
 	}
 }
+
+func TestEmptyConfig(t *testing.T) {
+	r := require.New(t)
+
+	_, err := NewFromFile("testdata/empty.yaml")
+	r.Error(err)
+	r.Equal(
+		"announcer: (local_address: cannot be blank; local_asn: cannot be blank; peers: cannot be blank; router_id: cannot be blank; routes: cannot be blank.); metrics: (address: cannot be blank; enabled: cannot be blank.); services: cannot be blank.",
+		err.Error(),
+	)
+}
+
+func TestEmptyAnnouncerOnlyConfig(t *testing.T) {
+	r := require.New(t)
+
+	// Actually there are no semantics checks so it should pass
+	_, err := NewFromFile("testdata/empty_with_announcer.yaml")
+	r.NoError(err)
+}

config/testdata/empty.yaml

@@ -0,0 +1 @@
+---

config/testdata/empty_with_announcer.yaml

@@ -0,0 +1,23 @@
+---
+announcer:
+  router_id: 10.3.3.3
+  local_address: 10.0.0.1
+  local_asn: 65999
+  routes:
+    - 10.0.0.128/32
+  peers:
+    - name: some_router_1
+      remote_address: 10.0.0.252
+      remote_asn: 65000
+    - name: some_router_2
+      remote_address: 10.0.0.253
+      remote_asn: 65000
+services:
+  - name: http
+    check_interval: 10s
+    checks:
+      - kind: dns_lookup
+        spec: {}
+metrics:
+  enabled: true
+  address: address

config/testdata/sample.json

@@ -22,7 +22,6 @@
   "services": [
     {
       "name": "http",
-      "check_operator": "and",
       "check_interval": "10s",
       "checks": [
         {

config/testdata/sample.yaml

@@ -14,7 +14,6 @@ announcer:
       remote_asn: 65000
 services:
   - name: http
-    check_operator: and
     check_interval: 10s
     checks:
       - kind: dns_lookup