Merge pull request #257 from alinrosca97/126-detailed-health-endpoint…

…-with-json-output

detailed json health check endpoint

http/router.go

@@ -62,6 +62,7 @@ func Router() *mux.Router {
 
 	r.Handle("/health", servicehealthcheck.HealthHandler())
 	r.Handle("/health/check", servicehealthcheck.ReadableHealthHandler())
+	r.Handle("/health/check.json", servicehealthcheck.JSONHealthHandler())
 
 	// for debugging purposes (e.g. deadlock, ...)
 	p := r.PathPrefix("/debug/pprof").Subrouter()

maintenance/health/servicehealthcheck/healthchecker.go

@@ -200,3 +200,10 @@ func HealthHandler() http.Handler {
 func ReadableHealthHandler() http.Handler {
 	return &readableHealthHandler{}
 }
+
+// JSONHealthHandler return health endpoint with all details about service health. This handler checks
+// all health checks. The response body contains a JSON formatted array with every service (required or optional)
+// and the detailed health checks about them.
+func JSONHealthHandler() http.Handler {
+	return &jsonHealthHandler{}
+}

maintenance/health/servicehealthcheck/healthchecker_test.go

@@ -5,6 +5,7 @@ package servicehealthcheck
 
 import (
 	"context"
+	"encoding/json"
 	"errors"
 	"io/ioutil"
 	"net/http"
@@ -247,6 +248,109 @@ func TestHandlerReadableHealthCheck(t *testing.T) {
 	}
 }
 
+func TestHandlerJSONHealthCheck(t *testing.T) {
+	warn := &testHealthChecker{name: "WithWarning", healthCheckWarn: true}
+	err := &testHealthChecker{name: "WithErr", healthCheckErr: true}
+	initErr := &testHealthChecker{name: "WithInitErr", initErr: true}
+
+	testcases := []struct {
+		title   string
+		req     []*testHealthChecker
+		opt     []*testHealthChecker
+		expCode int
+		expReq  []jsonHealthHandler
+	}{
+		{
+			title:   "Test health check json all required",
+			req:     []*testHealthChecker{warn, err, initErr},
+			opt:     []*testHealthChecker{},
+			expCode: http.StatusServiceUnavailable,
+			expReq: []jsonHealthHandler{
+				jsonHealthHandler{
+					Name:     err.name,
+					Status:   Err,
+					Required: true,
+					Error:    "healthCheckErr",
+				},
+				jsonHealthHandler{
+					Name:     initErr.name,
+					Status:   Err,
+					Required: true,
+					Error:    "initError",
+				},
+				jsonHealthHandler{
+					Name:     warn.name,
+					Status:   Ok,
+					Required: true,
+					Error:    "",
+				},
+			},
+		},
+		{
+			title:   "Test health check json some required, some optional",
+			req:     []*testHealthChecker{warn, err},
+			opt:     []*testHealthChecker{initErr},
+			expCode: http.StatusServiceUnavailable,
+			expReq: []jsonHealthHandler{
+				jsonHealthHandler{
+					Name:     err.name,
+					Status:   Err,
+					Required: true,
+					Error:    "healthCheckErr",
+				},
+				jsonHealthHandler{
+					Name:     initErr.name,
+					Status:   Err,
+					Required: false,
+					Error:    "initError",
+				},
+				jsonHealthHandler{
+					Name:     warn.name,
+					Status:   Ok,
+					Required: true,
+					Error:    "",
+				},
+			},
+		},
+	}
+	for _, tc := range testcases {
+		t.Run(tc.title, func(t *testing.T) {
+			resetHealthChecks()
+
+			rec := httptest.NewRecorder()
+			for _, hc := range tc.req {
+				RegisterHealthCheck(hc.name, hc)
+			}
+			for _, hc := range tc.opt {
+				RegisterOptionalHealthCheck(hc, hc.name)
+			}
+			req := httptest.NewRequest("GET", "/health/check", nil)
+			JSONHealthHandler().ServeHTTP(rec, req)
+			resp := rec.Result()
+
+			require.Equal(t, tc.expCode, resp.StatusCode)
+
+			var data []jsonHealthHandler
+			err := json.NewDecoder(resp.Body).Decode(&data)
+			require.NoError(t, err)
+
+			sort.Slice(data, func(i, j int) bool {
+				return data[i].Name < data[j].Name
+			})
+			sort.Slice(tc.expReq, func(i, j int) bool {
+				return tc.expReq[i].Name < tc.expReq[j].Name
+			})
+
+			for i := range tc.expReq {
+				require.Equal(t, tc.expReq[i].Name, data[i].Name)
+				require.Equal(t, tc.expReq[i].Status, data[i].Status)
+				require.Equal(t, tc.expReq[i].Required, data[i].Required)
+				require.Equal(t, tc.expReq[i].Error, data[i].Error)
+			}
+		})
+	}
+}
+
 func testListHealthChecks(expected []string, checkResult []string, t *testing.T) {
 	// checkResult contains a empty string because of the splitting
 	require.Equal(t, len(expected), len(checkResult)-1, "The amount of health check results in the response body needs to be equal to the amount of expected health check results.")

maintenance/health/servicehealthcheck/json_health_handler.go

@@ -0,0 +1,62 @@
+package servicehealthcheck
+
+import (
+	"encoding/json"
+	"net/http"
+
+	"github.com/pace/bricks/maintenance/log"
+)
+
+type jsonHealthHandler struct {
+	Name     string      `json: "name"`
+	Status   HealthState `json: "status"`
+	Required bool        `json: "required"`
+	Error    string      `json: "error"`
+}
+
+func (h *jsonHealthHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	log.Debug("JSON HTTP handler")
+	s := log.Sink{Silent: true}
+	ctx := log.ContextWithSink(r.Context(), &s)
+
+	reqChecks := check(ctx, &requiredChecks)
+	optChecks := check(ctx, &optionalChecks)
+
+	checkResponse := make([]jsonHealthHandler, len(reqChecks)+len(optChecks))
+	index := 0
+
+	status := http.StatusOK
+	for name, res := range reqChecks {
+		scr := jsonHealthHandler{
+			Name:     name,
+			Status:   res.State,
+			Required: true,
+			Error:    "",
+		}
+		if res.State == Err {
+			scr.Error = res.Msg
+			status = http.StatusServiceUnavailable
+		}
+		checkResponse[index] = scr
+		index++
+	}
+
+	for name, res := range optChecks {
+		scr := jsonHealthHandler{
+			Name:     name,
+			Status:   res.State,
+			Required: false,
+			Error:    "",
+		}
+		if res.State == Err {
+			scr.Error = res.Msg
+			status = http.StatusServiceUnavailable
+		}
+		checkResponse[index] = scr
+		index++
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	json.NewEncoder(w).Encode(checkResponse)
+}