Merge pull request 'Major enhancements' (#6) from enhancements into devel

Reviewed-on: #6

README.md

@@ -10,19 +10,23 @@ go get -u pkg.icikowski.pl/kubeprobes
 
 ## Usage
 
-The package provides `kubeprobes.New` function which returns a probes handler compliant with `http.Handler` interface.
+The package provides `kubeprobes.New` function which returns a probes handler of type `kubeprobes.Kubeprobes`, which is compliant with `http.Handler` interface.
 
 The handler serves two endpoints, which are used to implement liveness and readiness probes by returning either `200` (healthy) or `503` (unhealthy) status:
 
 - `/live` - endpoint for liveness probe;
 - `/ready` - endpoint for readiness probe.
 
-Accessing any other endpoint will return `404` status. In order to provide maximum performance, no body is ever returned.
+Default paths can be overriden with options described below. Accessing any other endpoint will return `404` status. In order to provide maximum performance, no body is ever returned.
 
-The `kubeprobes.New` function accepts following options-applying functions as arguments:
+The `kubeprobes.New` function accepts following options as arguments:
 
-- `kubeprobes.WithLivenessProbes(/* ... */)` - adds particular [probes](#probes) to the list of liveness probes;
+- `kubeprobes.WithLivenessProbes(...)` - adds particular [probe functions](#probe-functions) to the list of liveness probes;
-- `kubeprobes.WithReadinessProbes(/* ... */)` - adds particular [probes](#probes) to the list of readiness probes.
+- `kubeprobes.WithLivenessStatefulProbes(...)` - adds particular [`StatefulProbe`s](#stateful-probes) to the list of liveness probes;
+- `kubeprobes.WithLivenessPath("/some/liveness/path")` - sets liveness probe path to given path (default is `/live`);
+- `kubeprobes.WithReadinessProbes(...)` - adds particular [probe functions](#probe-functions) to the list of readiness probes;
+- `kubeprobes.WithReadinessStatefulProbes(...)` - adds particular [`StatefulProbe`s](#stateful-probes) to the list of readiness probes;
+- `kubeprobes.WithReadinessPath("/some/readiness/path")` - sets readiness probe path to given path (default is `/ready`).
 
 ## Probes
 
@@ -47,7 +51,7 @@ someOtherProbe := func() error {
 } 
 
 // Use functions in probes handler
-kp := kubeprobes.New(
+kp, _ := kubeprobes.New(
     kubeprobes.WithLivenessProbes(someOtherProbe),
     kubeprobes.WithReadinessProbes(someProbe),
 )
@@ -63,24 +67,52 @@ someProbe := kubeprobes.NewStatefulProbe()
 someOtherProbe := kubeprobes.NewStatefulProbe()
 
 // Use it in probes handler
-kp := kubeprobes.New(
+kp, _ := kubeprobes.New(
-    kubeprobes.WithLivenessProbes(someProbe.GetProbeFunction()),
+    kubeprobes.WithLivenessStatefulProbes(someProbe),
-    kubeprobes.WithReadinessProbes(someOtherProbe.GetProbeFunction()),
+    kubeprobes.WithReadinessStatefulProbes(someOtherProbe),
 )
 ```
 
+## Direct handler access
+
+It is possible to fetch `http.Handler`s for liveness & readiness probes from `kubeprobes.Kubeprobes` instance as follows:
+
+```go
+kp, _ := kubeprobes.New(
+    // ...
+)
+
+livenessHandler := kp.GetLivenessHandler()
+readinessHandler := kp.GetReadinessHandler()
+```
+
+Those handler can be used for manually mounting them on other servers/routers/muxes (eg. `go-chi/chi`, `gorilla/mux`, `http`'s `ServeMux` etc.). 
+
 ## Example usage
 
 ```go
+// Create probe functions
+appProbe := func() error {
+    // Some logic for checking app status
+    return nil
+}
+
 // Create stateful probes
 live := kubeprobes.NewStatefulProbe() 
 ready := kubeprobes.NewStatefulProbe()
 
 // Prepare handler
-kp := kubeprobes.New(
+kp, err := kubeprobes.New(
-    kubeprobes.WithLivenessProbes(live.GetProbeFunction()),
+    kubeprobes.WithLivenessStatefulProbes(live),
-    kubeprobes.WithReadinessProbes(ready.GetProbeFunction()),
+    kubeprobes.WithReadinessStatefulProbes(ready),
+    kubeprobes.WithReadinessProbes(appProbe),
+    kubeprobes.WithLivenessPath("/livez"),
+    kubeprobes.WithReadinessPath("/readyz"),
 )
+if err != nil {
+    // Kubeprobes object is validated for invalid or conflicting paths! ;)
+    panic(err)
+}
 
 // Start the probes server
 probes := &http.Server{

costants.go

@@ -0,0 +1,7 @@
+package kubeprobes
+
+const (
+	defaultLivenessPath  string = "/live"
+	defaultReadinessPath string = "/ready"
+	verboseOutputFlag    string = "v"
+)

options.go

@@ -0,0 +1,67 @@
+package kubeprobes
+
+type option struct {
+	fn func(*kubeprobes)
+}
+
+func (o *option) apply(kp *kubeprobes) {
+	o.fn(kp)
+}
+
+// WithLivenessProbes adds given probe functions to the set of liveness probes.
+func WithLivenessProbes(probes ...ProbeFunction) Option {
+	return &option{
+		fn: func(kp *kubeprobes) {
+			kp.livenessProbes = append(kp.livenessProbes, probes...)
+		},
+	}
+}
+
+// WithLivenessStatefulProbes adds given [StatefulProbe]s to the set of liveness probes.
+func WithLivenessStatefulProbes(probes ...*StatefulProbe) Option {
+	return &option{
+		fn: func(kp *kubeprobes) {
+			for _, p := range probes {
+				kp.livenessProbes = append(kp.livenessProbes, p.GetProbeFunction())
+			}
+		},
+	}
+}
+
+// WithLivenessPath sets custom path for liveness probe (default is "/live").
+func WithLivenessPath(path string) Option {
+	return &option{
+		fn: func(kp *kubeprobes) {
+			kp.pathLive = path
+		},
+	}
+}
+
+// WithReadinessProbes adds given probe functions to the set of readiness probes.
+func WithReadinessProbes(probes ...ProbeFunction) Option {
+	return &option{
+		fn: func(kp *kubeprobes) {
+			kp.readinessProbes = append(kp.readinessProbes, probes...)
+		},
+	}
+}
+
+// WithReadinessProbes adds given [StatefulProbe]s to the set of readiness probes.
+func WithReadinessStatefulProbes(probes ...*StatefulProbe) Option {
+	return &option{
+		fn: func(kp *kubeprobes) {
+			for _, p := range probes {
+				kp.readinessProbes = append(kp.readinessProbes, p.GetProbeFunction())
+			}
+		},
+	}
+}
+
+// WithReadinessPath sets custom path for readiness probe (default is "/ready").
+func WithReadinessPath(path string) Option {
+	return &option{
+		fn: func(kp *kubeprobes) {
+			kp.pathReady = path
+		},
+	}
+}

probes.go

@@ -1,6 +1,8 @@
 package kubeprobes
 
 import (
+	"errors"
+	"fmt"
 	"net/http"
 	"strings"
 )
@@ -8,57 +10,107 @@ import (
 type kubeprobes struct {
 	livenessProbes  []ProbeFunction
 	readinessProbes []ProbeFunction
+
+	pathLive  string
+	pathReady string
 }
 
-// ServeHTTP implements http.Handler interface
+// New returns a new instance of a Kubernetes probes with given options.
-func (kp *kubeprobes) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+func New(options ...Option) (Kubeprobes, error) {
-	subs := strings.Split(strings.TrimSuffix(r.URL.Path, "/"), "/")
+	kp := &kubeprobes{
-	switch subs[len(subs)-1] {
+		livenessProbes:  []ProbeFunction{},
-	case "live":
+		readinessProbes: []ProbeFunction{},
+		pathLive:        "/live",
+		pathReady:       "/ready",
+	}
+
+	for _, option := range options {
+		option.apply(kp)
+	}
+
+	if err := kp.validate(); err != nil {
+		return nil, err
+	}
+	return kp, nil
+}
+
+func (kp *kubeprobes) validate() error {
+	errs := []error{}
+
+	if kp.pathLive == "" {
+		errs = append(
+			errs,
+			fmt.Errorf("liveness probe path must not be empty"),
+		)
+	}
+
+	if kp.pathReady == "" {
+		errs = append(
+			errs,
+			fmt.Errorf("readiness probe path must not be empty"),
+		)
+	}
+
+	if !strings.HasPrefix(kp.pathLive, "/") {
+		errs = append(
+			errs,
+			fmt.Errorf("liveness probe path must start with slash (current: %q)", kp.pathLive),
+		)
+	}
+
+	if !strings.HasPrefix(kp.pathReady, "/") {
+		errs = append(
+			errs,
+			fmt.Errorf("readiness probe path must start with slash (current: %q)", kp.pathReady),
+		)
+	}
+
+	if kp.pathLive == kp.pathReady {
+		errs = append(
+			errs,
+			fmt.Errorf("liveness and readiness probes have the same values (both %q)", kp.pathLive),
+		)
+	}
+
+	return errors.Join(errs...)
+}
+
+func (kp *kubeprobes) handleLiveness(w http.ResponseWriter, _ *http.Request) {
 	sq := newStatusQuery(kp.livenessProbes)
 	if sq.isAllGreen() {
 		w.WriteHeader(http.StatusOK)
 	} else {
 		w.WriteHeader(http.StatusServiceUnavailable)
 	}
-	case "ready":
+}
+
+func (kp *kubeprobes) handleReadiness(w http.ResponseWriter, _ *http.Request) {
 	sq := newStatusQuery(append(kp.livenessProbes, kp.readinessProbes...))
 	if sq.isAllGreen() {
 		w.WriteHeader(http.StatusOK)
 	} else {
 		w.WriteHeader(http.StatusServiceUnavailable)
 	}
+}
+
+// GetLivenessHandler implements Kubeprobes.
+func (kp *kubeprobes) GetLivenessHandler() http.Handler {
+	return http.HandlerFunc(kp.handleLiveness)
+}
+
+// GetReadinessHandler implements Kubeprobes.
+func (kp *kubeprobes) GetReadinessHandler() http.Handler {
+	return http.HandlerFunc(kp.handleReadiness)
+}
+
+// ServeHTTP implements Kubeprobes.
+func (kp *kubeprobes) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	switch r.URL.Path {
+	case kp.pathLive:
+		kp.handleLiveness(w, r)
+	case kp.pathReady:
+		kp.handleReadiness(w, r)
 	default:
 		w.WriteHeader(http.StatusNotFound)
 	}
 }
-
-type option func(*kubeprobes)
-
-// New returns a new instance of a Kubernetes probes
-func New(options ...option) *kubeprobes {
-	kp := &kubeprobes{
-		livenessProbes:  []ProbeFunction{},
-		readinessProbes: []ProbeFunction{},
-	}
-
-	for _, option := range options {
-		option(kp)
-	}
-
-	return kp
-}
-
-// WithLivenessProbes adds given liveness probes to the set of probes
-func WithLivenessProbes(probes ...ProbeFunction) option {
-	return func(kp *kubeprobes) {
-		kp.livenessProbes = append(kp.livenessProbes, probes...)
-	}
-}
-
-// WithReadinessProbes adds given readiness probes to the set of probes
-func WithReadinessProbes(probes ...ProbeFunction) option {
-	return func(kp *kubeprobes) {
-		kp.readinessProbes = append(kp.readinessProbes, probes...)
-	}
-}

probes_test.go

@@ -50,9 +50,9 @@ func TestKubeprobes(t *testing.T) {
 		},
 	}
 
-	kp := New(
+	kp, _ := New(
-		WithLivenessProbes(live.GetProbeFunction()),
+		WithLivenessStatefulProbes(live),
-		WithReadinessProbes(ready.GetProbeFunction()),
+		WithReadinessStatefulProbes(ready),
 	)
 
 	srv := httptest.NewServer(kp)
@@ -65,8 +65,8 @@ func TestKubeprobes(t *testing.T) {
 			test.livenessProbeTransformation(t, live)
 			test.readinessProbeTransformation(t, ready)
 
-			liveStatus := getStatusFromEndpoint(t, client, srv.URL+"/live")
+			liveStatus := getStatusFromEndpoint(t, client, srv.URL+defaultLivenessPath)
-			readyStatus := getStatusFromEndpoint(t, client, srv.URL+"/ready")
+			readyStatus := getStatusFromEndpoint(t, client, srv.URL+defaultReadinessPath)
 			otherStatus := getStatusFromEndpoint(t, client, srv.URL+"/something")
 
 			if liveStatus != test.expectedLiveStatus {

query.go

@@ -2,11 +2,6 @@ package kubeprobes
 
 import "sync"
 
-// ProbeFunction is a function that determines whether
-// the given metric may be marked as correctly functioning.
-// It not, the error should be returned.
-type ProbeFunction func() error
-
 type statusQuery struct {
 	allGreen bool
 	mux      sync.Mutex

stateful_probe.go

@@ -5,13 +5,13 @@ import (
 	"sync"
 )
 
-var errProbeDown = errors.New("DOWN")
+var errProbeDown = errors.New("probe is down")
 
 // StatefulProbe represents the simple probe that can be either
 // marked as "up" (healthy) or "down" (unhealthy).
 type StatefulProbe struct {
-	status bool
 	mux    sync.Mutex
+	status bool
 }
 
 // NewStatefulProbe returns a new instance of a stateful probe
@@ -19,19 +19,19 @@ type StatefulProbe struct {
 // The probe is initially marked as "down".
 func NewStatefulProbe() *StatefulProbe {
 	return &StatefulProbe{
-		status: false,
 		mux:    sync.Mutex{},
+		status: false,
 	}
 }
 
-// MarkAsUp marks the probe as healthy
+// MarkAsUp marks the probe as healthy.
 func (sp *StatefulProbe) MarkAsUp() {
 	sp.mux.Lock()
 	defer sp.mux.Unlock()
 	sp.status = true
 }
 
-// MarkAsDown marks the probe as unhealthy
+// MarkAsDown marks the probe as unhealthy.
 func (sp *StatefulProbe) MarkAsDown() {
 	sp.mux.Lock()
 	defer sp.mux.Unlock()

types.go

@@ -0,0 +1,23 @@
+package kubeprobes
+
+import "net/http"
+
+// Kubeprobes represents liveness & readiness probes handler.
+type Kubeprobes interface {
+	http.Handler
+
+	// GetLivenessHandler returns [http.Handler] for liveness probes.
+	GetLivenessHandler() http.Handler
+	// GetReadinessHandler returns [http.Handler] for readiness probes.
+	GetReadinessHandler() http.Handler
+}
+
+// Option represents a [Kubeprobes] constructor option.
+type Option interface {
+	apply(kp *kubeprobes)
+}
+
+// ProbeFunction is a function that determines whether
+// the given metric may be marked as correctly functioning.
+// It not, the error should be returned.
+type ProbeFunction func() error