refactor: mv api and metrics to dedicated packages

pkg/api/api.go

@@ -0,0 +1,203 @@
+// sparrow
+// (C) 2023, Deutsche Telekom IT GmbH
+//
+// Deutsche Telekom IT GmbH and all other contributors /
+// copyright owners license this file to you under the Apache
+// License, Version 2.0 (the "License"); you may not use this
+// file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+package api
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"net/http"
+	"time"
+
+	"github.com/caas-team/sparrow/internal/logger"
+	"github.com/caas-team/sparrow/pkg/api/router"
+	"github.com/caas-team/sparrow/pkg/checks"
+	"github.com/caas-team/sparrow/pkg/config"
+	"github.com/getkin/kin-openapi/openapi3"
+	"github.com/go-chi/chi/v5"
+)
+
+type API struct {
+	server      *http.Server
+	RoutingTree *router.RoutingTree
+	router      chi.Router
+}
+
+const (
+	readHeaderTimeout = time.Second * 5
+	shutdownTimeout   = 30 * time.Second
+)
+
+var ErrCreateOpenapiSchema = errors.New("failed to get schema for check")
+
+func New(config *config.ApiConfig) *API {
+	r := chi.NewRouter()
+	return &API{
+		server:      &http.Server{Addr: config.ListeningAddress, Handler: r, ReadHeaderTimeout: readHeaderTimeout},
+		RoutingTree: router.NewRoutingTree(),
+		router:      r,
+	}
+}
+
+// Run serves the data api
+// Blocks until context is done
+func (a *API) Run(ctx context.Context) error {
+	log := logger.FromContext(ctx)
+	cErr := make(chan error, 1)
+
+	// run http server in goroutine
+	go func(cErr chan error) {
+		defer close(cErr)
+		log.Info("Serving Api", "addr", a.server.Addr)
+		if err := a.server.ListenAndServe(); err != nil {
+			log.Error("Failed to serve api", "error", err)
+			cErr <- err
+		}
+	}(cErr)
+
+	select {
+	case <-ctx.Done():
+		return fmt.Errorf("failed serving API: %w", ctx.Err())
+	case err := <-cErr:
+		if errors.Is(err, http.ErrServerClosed) || err == nil {
+			log.Info("Api server closed")
+			return nil
+		}
+		log.Error("failed serving API", "error", err)
+		return fmt.Errorf("failed serving API: %w", err)
+	}
+}
+
+// Shutdown gracefully shuts down the api server
+// Returns an error if an error is present in the context
+// or if the server cannot be shut down
+func (a *API) Shutdown(ctx context.Context) error {
+	errC := ctx.Err()
+	log := logger.FromContext(ctx)
+	shutdownCtx, cancel := context.WithTimeout(context.Background(), shutdownTimeout)
+	defer cancel()
+	err := a.server.Shutdown(shutdownCtx)
+	if err != nil {
+		log.Error("Failed to shutdown api server", "error", err)
+		return fmt.Errorf("failed shutting down API: %w", errors.Join(errC, err))
+	}
+	return errC
+}
+
+type Route struct {
+	Path    string
+	Method  string
+	Handler http.HandlerFunc
+}
+
+func (a *API) RegisterRoutes(ctx context.Context, routes ...Route) error {
+	a.router.Use(logger.Middleware(ctx))
+	for _, route := range routes {
+		switch route.Method {
+		case http.MethodGet:
+			a.router.Get(route.Path, route.Handler)
+		case http.MethodPost:
+			a.router.Post(route.Path, route.Handler)
+		case http.MethodPut:
+			a.router.Put(route.Path, route.Handler)
+		case http.MethodDelete:
+			a.router.Delete(route.Path, route.Handler)
+		case http.MethodPatch:
+			a.router.Patch(route.Path, route.Handler)
+		case "Handle":
+			a.router.Handle(route.Path, route.Handler)
+		case "HandleFunc":
+			a.router.HandleFunc(route.Path, route.Handler)
+		default:
+			return fmt.Errorf("unsupported method: %s", route.Method)
+		}
+	}
+
+	// Handles requests with simple http ok
+	// Required for global tarMan in checks
+	a.router.Handle("/", okHandler(ctx))
+
+	return nil
+
+}
+
+// okHandler returns a handler that will serve status ok
+func okHandler(ctx context.Context) http.Handler {
+	log := logger.FromContext(ctx)
+
+	return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
+		w.WriteHeader(http.StatusOK)
+		_, err := w.Write([]byte("ok"))
+		if err != nil {
+			log.Error("Could not write response", "error", err.Error())
+		}
+	})
+}
+
+var oapiBoilerplate = openapi3.T{
+	// this object should probably be user defined
+	OpenAPI: "3.0.0",
+	Info: &openapi3.Info{
+		Title:       "Sparrow Metrics API",
+		Description: "Serves metrics collected by sparrows checks",
+		Contact: &openapi3.Contact{
+			URL:   "https://caas.telekom.de",
+			Email: "[email protected]",
+			Name:  "CaaS Team",
+		},
+	},
+	Paths:      make(openapi3.Paths),
+	Extensions: make(map[string]any),
+	Components: &openapi3.Components{
+		Schemas: make(openapi3.Schemas),
+	},
+	Servers: openapi3.Servers{},
+}
+
+func OpenAPI(ctx context.Context, checks map[string]checks.Check) (openapi3.T, error) {
+	log := logger.FromContext(ctx)
+	doc := oapiBoilerplate
+	for name, c := range checks {
+		ref, err := c.Schema()
+		if err != nil {
+			log.Error("failed to get schema for check", "error", err)
+			return openapi3.T{}, fmt.Errorf("%w %s: %w", ErrCreateOpenapiSchema, name, err)
+		}
+
+		routeDesc := fmt.Sprintf("Returns the performance data for check %s", name)
+		bodyDesc := fmt.Sprintf("Metrics for check %s", name)
+		doc.Paths["/v1/metrics/"+name] = &openapi3.PathItem{
+			Description: name,
+			Get: &openapi3.Operation{
+				Description: routeDesc,
+				Tags:        []string{"Metrics", name},
+				Responses: openapi3.Responses{
+					"200": &openapi3.ResponseRef{
+						Value: &openapi3.Response{
+							Description: &bodyDesc,
+							Content:     openapi3.NewContentWithSchemaRef(ref, []string{"application/json"}),
+						},
+					},
+				},
+			},
+		}
+	}
+
+	return doc, nil
+}

pkg/api/routingtree.go → pkg/api/router/routingtree.go

@@ -16,7 +16,7 @@
 // specific language governing permissions and limitations
 // under the License.
 
-package api
+package router
 
 import (
 	"net/http"

pkg/api/routingtree_test.go → pkg/api/router/routingtree_test.go

@@ -16,7 +16,7 @@
 // specific language governing permissions and limitations
 // under the License.
 
-package api
+package router
 
 import (
 	"net/http"

pkg/sparrow/metrics.go → pkg/metrics/metrics.go

@@ -16,7 +16,7 @@
 // specific language governing permissions and limitations
 // under the License.
 
-package sparrow
+package metrics
 
 import (
 	"github.com/prometheus/client_golang/prometheus"

pkg/sparrow/metrics_test.go → pkg/metrics/metrics_test.go

@@ -16,7 +16,7 @@
 // specific language governing permissions and limitations
 // under the License.
 
-package sparrow
+package metrics
 
 import (
 	"reflect"