Add GET /_health endpoint

Return 500 if not ok and 200 if ok.
The response will contains a map of string/string for each checks.
The value is 'OK' if the check passed, otherwise, is is the error.

cmd/container_test.go

@@ -2,7 +2,7 @@ package cmd
 
 import (
 	"context"
-	"github.com/numary/ledger/pkg/ledgertesting"
+	"github.com/numary/ledger/internal/pgtesting"
 	"github.com/numary/ledger/pkg/opentelemetry/opentelemetrytraces"
 	"github.com/numary/ledger/pkg/storage"
 	"github.com/numary/ledger/pkg/storage/sqlstorage"
@@ -19,7 +19,7 @@ import (
 
 func TestContainers(t *testing.T) {
 
-	pgServer, err := ledgertesting.PostgresServer()
+	pgServer, err := pgtesting.PostgresServer()
 	assert.NoError(t, err)
 	defer pgServer.Close()
 

cmd/root_test.go

@@ -3,7 +3,7 @@ package cmd
 import (
 	"bytes"
 	"context"
-	"github.com/numary/ledger/pkg/ledgertesting"
+	"github.com/numary/ledger/internal/pgtesting"
 	"github.com/pborman/uuid"
 	"github.com/sirupsen/logrus"
 	"github.com/stretchr/testify/assert"
@@ -19,7 +19,7 @@ func TestServer(t *testing.T) {
 		logrus.SetLevel(logrus.DebugLevel)
 	}
 
-	pgServer, err := ledgertesting.PostgresServer()
+	pgServer, err := pgtesting.PostgresServer()
 	assert.NoError(t, err)
 	defer pgServer.Close()
 

pkg/ledgertesting/testing.go → internal/pgtesting/testing.go

@@ -1,4 +1,4 @@
-package ledgertesting
+package pgtesting
 
 import (
 	"context"

pkg/api/controllers/controllers.go

@@ -1,40 +1,44 @@
 package controllers
 
 import (
+	"github.com/numary/ledger/pkg/health"
 	"go.uber.org/fx"
 )
 
 const (
-	VersionKey       = `name:"_apiVersion"`
-	StorageDriverKey = `name:"_apiStorageDriver"`
-	LedgerListerKey  = `name:"_apiLedgerLister"`
+	versionKey       = `name:"_apiVersion"`
+	storageDriverKey = `name:"_apiStorageDriver"`
+	ledgerListerKey  = `name:"_apiLedgerLister"`
 )
 
 func ProvideVersion(provider interface{}) fx.Option {
 	return fx.Provide(
-		fx.Annotate(provider, fx.ResultTags(VersionKey)),
+		fx.Annotate(provider, fx.ResultTags(versionKey)),
 	)
 }
 
 func ProvideStorageDriver(provider interface{}) fx.Option {
 	return fx.Provide(
-		fx.Annotate(provider, fx.ResultTags(StorageDriverKey)),
+		fx.Annotate(provider, fx.ResultTags(storageDriverKey)),
 	)
 }
 
 func ProvideLedgerLister(provider interface{}) fx.Option {
 	return fx.Provide(
-		fx.Annotate(provider, fx.ResultTags(LedgerListerKey)),
+		fx.Annotate(provider, fx.ResultTags(ledgerListerKey)),
 	)
 }
 
 var Module = fx.Options(
 	fx.Provide(
-		fx.Annotate(NewConfigController, fx.ParamTags(VersionKey, StorageDriverKey, LedgerListerKey)),
+		fx.Annotate(NewConfigController, fx.ParamTags(versionKey, storageDriverKey, ledgerListerKey)),
 	),
 	fx.Provide(NewLedgerController),
 	fx.Provide(NewScriptController),
 	fx.Provide(NewAccountController),
 	fx.Provide(NewTransactionController),
 	fx.Provide(NewMappingController),
+	fx.Provide(
+		fx.Annotate(NewHealthController, fx.ParamTags(health.HealthCheckKey)),
+	),
 )

pkg/api/controllers/health_controller.go

@@ -0,0 +1,58 @@
+package controllers
+
+import (
+	"github.com/gin-gonic/gin"
+	"github.com/numary/ledger/pkg/health"
+	"net/http"
+	"sync"
+)
+
+type HealthController struct {
+	Checks []health.NamedCheck
+}
+
+func (ctrl *HealthController) Check(c *gin.Context) {
+	w := sync.WaitGroup{}
+	w.Add(len(ctrl.Checks))
+	type R struct {
+		Check health.NamedCheck
+		Err   error
+	}
+	results := make(chan R, len(ctrl.Checks))
+	for _, ch := range ctrl.Checks {
+		go func(ch health.NamedCheck) {
+			defer w.Done()
+			select {
+			case <-c.Request.Context().Done():
+				return
+			case results <- R{
+				Check: ch,
+				Err:   ch.Do(c.Request.Context()),
+			}:
+			}
+		}(ch)
+	}
+	w.Wait()
+	close(results)
+	response := map[string]string{}
+	hasError := false
+	for r := range results {
+		if r.Err != nil {
+			hasError = true
+			response[r.Check.Name()] = r.Err.Error()
+		} else {
+			response[r.Check.Name()] = "OK"
+		}
+	}
+	status := http.StatusOK
+	if hasError {
+		status = http.StatusInternalServerError
+	}
+	c.JSON(status, response)
+}
+
+func NewHealthController(checks []health.NamedCheck) HealthController {
+	return HealthController{
+		Checks: checks,
+	}
+}

pkg/api/controllers/health_controller_test.go

@@ -0,0 +1,96 @@
+package controllers_test
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"github.com/numary/ledger/pkg/api"
+	"github.com/numary/ledger/pkg/api/internal"
+	"github.com/numary/ledger/pkg/health"
+	"github.com/stretchr/testify/assert"
+	"go.uber.org/fx"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestHealthController(t *testing.T) {
+
+	type testCase struct {
+		name                 string
+		healthChecksProvider []interface{}
+		expectedStatus       int
+		expectedResult       map[string]string
+	}
+
+	var tests = []testCase{
+		{
+			name: "all-ok",
+			healthChecksProvider: []interface{}{
+				func() health.NamedCheck {
+					return health.NewNamedCheck("test1", health.CheckFn(func(ctx context.Context) error {
+						return nil
+					}))
+				},
+				func() health.NamedCheck {
+					return health.NewNamedCheck("test2", health.CheckFn(func(ctx context.Context) error {
+						return nil
+					}))
+				},
+			},
+			expectedStatus: http.StatusOK,
+			expectedResult: map[string]string{
+				"test1": "OK",
+				"test2": "OK",
+			},
+		},
+		{
+			name: "one-failing",
+			healthChecksProvider: []interface{}{
+				func() health.NamedCheck {
+					return health.NewNamedCheck("test1", health.CheckFn(func(ctx context.Context) error {
+						return nil
+					}))
+				},
+				func() health.NamedCheck {
+					return health.NewNamedCheck("test2", health.CheckFn(func(ctx context.Context) error {
+						return errors.New("failure")
+					}))
+				},
+			},
+			expectedStatus: http.StatusInternalServerError,
+			expectedResult: map[string]string{
+				"test1": "OK",
+				"test2": "failure",
+			},
+		},
+	}
+
+	for _, tc := range tests {
+
+		options := make([]fx.Option, 0)
+		for _, p := range tc.healthChecksProvider {
+			options = append(options, health.ProvideHealthCheck(p))
+		}
+
+		internal.RunSubTest(t, tc.name, func(h *api.API) {
+			rec := httptest.NewRecorder()
+			req := httptest.NewRequest("GET", "/_health", nil)
+
+			h.ServeHTTP(rec, req)
+
+			if !assert.Equal(t, tc.expectedStatus, rec.Result().StatusCode) {
+				return
+			}
+			ret := make(map[string]string)
+			err := json.NewDecoder(rec.Result().Body).Decode(&ret)
+			if !assert.NoError(t, err) {
+				return
+			}
+			if !assert.Equal(t, tc.expectedResult, ret) {
+				return
+			}
+		}, options...)
+	}
+
+}

pkg/api/controllers/transaction_controller_test.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"database/sql"
 	"encoding/json"
+	"github.com/numary/ledger/internal/pgtesting"
 	"github.com/numary/ledger/pkg/api"
 	"github.com/numary/ledger/pkg/api/controllers"
 	"github.com/numary/ledger/pkg/api/internal"
@@ -311,7 +312,7 @@ func TestTooManyClient(t *testing.T) {
 		assert.NoError(t, err)
 
 		// Grab all potential connections
-		for i := 0; i < ledgertesting.MaxConnections; i++ {
+		for i := 0; i < pgtesting.MaxConnections; i++ {
 			tx, err := store.(*sqlstorage.Store).DB().BeginTx(context.Background(), &sql.TxOptions{})
 			assert.NoError(t, err)
 			defer tx.Rollback()

pkg/api/internal/testing.go

@@ -183,12 +183,12 @@ func WithNewModule(t *testing.T, options ...fx.Option) {
 	}
 }
 
-func RunSubTest(t *testing.T, name string, fn interface{}) {
+func RunSubTest(t *testing.T, name string, fn interface{}, opts ...fx.Option) {
 	t.Run(name, func(t *testing.T) {
-		RunTest(t, fn)
+		RunTest(t, fn, opts...)
 	})
 }
 
-func RunTest(t *testing.T, fn interface{}) {
-	WithNewModule(t, fx.Invoke(fn))
+func RunTest(t *testing.T, fn interface{}, opts ...fx.Option) {
+	WithNewModule(t, append(opts, fx.Invoke(fn))...)
 }

pkg/api/routes/routes.go

@@ -35,6 +35,7 @@ func ProvidePerLedgerMiddleware(provider interface{}, additionalAnnotations ...f
 type Routes struct {
 	resolver              *ledger.Resolver
 	ledgerMiddleware      middlewares.LedgerMiddleware
+	healthController      controllers.HealthController
 	configController      controllers.ConfigController
 	ledgerController      controllers.LedgerController
 	scriptController      controllers.ScriptController
@@ -57,6 +58,7 @@ func NewRoutes(
 	accountController controllers.AccountController,
 	transactionController controllers.TransactionController,
 	mappingController controllers.MappingController,
+	healthController controllers.HealthController,
 ) *Routes {
 	return &Routes{
 		globalMiddlewares:     globalMiddlewares,
@@ -69,6 +71,7 @@ func NewRoutes(
 		accountController:     accountController,
 		transactionController: transactionController,
 		mappingController:     mappingController,
+		healthController:      healthController,
 	}
 }
 
@@ -79,6 +82,7 @@ func (r *Routes) Engine() *gin.Engine {
 	// Default Middlewares
 	engine.Use(r.globalMiddlewares...)
 
+	engine.GET("/_health", r.healthController.Check)
 	engine.GET("/swagger.yaml", r.configController.GetDocsAsYaml)
 	engine.GET("/swagger.json", r.configController.GetDocsAsJSON)
 

pkg/health/health.go

@@ -0,0 +1,33 @@
+package health
+
+import "context"
+
+type Check interface {
+	Do(ctx context.Context) error
+}
+type CheckFn func(ctx context.Context) error
+
+func (fn CheckFn) Do(ctx context.Context) error {
+	return fn(ctx)
+}
+
+type NamedCheck interface {
+	Check
+	Name() string
+}
+
+type simpleNamedCheck struct {
+	Check
+	name string
+}
+
+func (c *simpleNamedCheck) Name() string {
+	return c.name
+}
+
+func NewNamedCheck(name string, check Check) *simpleNamedCheck {
+	return &simpleNamedCheck{
+		Check: check,
+		name:  name,
+	}
+}

pkg/health/module.go

@@ -0,0 +1,11 @@
+package health
+
+import "go.uber.org/fx"
+
+const HealthCheckKey = `group:"_healthCheck"`
+
+func ProvideHealthCheck(provider interface{}) fx.Option {
+	return fx.Provide(
+		fx.Annotate(provider, fx.ResultTags(HealthCheckKey)),
+	)
+}

pkg/ledger/resolver.go

@@ -3,7 +3,6 @@ package ledger
 import (
 	"context"
 	"github.com/numary/ledger/pkg/storage"
-	"github.com/numary/ledger/pkg/storage/sqlstorage"
 	"github.com/pkg/errors"
 	"go.uber.org/fx"
 	"sync"
@@ -33,7 +32,6 @@ func WithLocker(locker Locker) ResolveOptionFn {
 }
 
 var DefaultResolverOptions = []ResolverOption{
-	WithStorageFactory(storage.NewDefaultFactory(sqlstorage.NewInMemorySQLiteDriver())),
 	WithLocker(NewInMemoryLocker()),
 }
 
@@ -44,7 +42,7 @@ type Resolver struct {
 	initializedStores map[string]struct{}
 }
 
-func NewResolver(options ...ResolverOption) *Resolver {
+func NewResolver(storageFactory storage.Factory, options ...ResolverOption) *Resolver {
 	options = append(DefaultResolverOptions, options...)
 	r := &Resolver{
 		initializedStores: map[string]struct{}{},
@@ -100,7 +98,7 @@ func ProvideResolverOption(provider interface{}) fx.Option {
 func ResolveModule() fx.Option {
 	return fx.Options(
 		fx.Provide(
-			fx.Annotate(NewResolver, fx.ParamTags(ResolverOptionsKey)),
+			fx.Annotate(NewResolver, fx.ParamTags("", ResolverOptionsKey)),
 		),
 		ProvideResolverOption(WithStorageFactory),
 	)