context_test.go

// Copyright 2015 Matthew Holt and The Caddy Authors
//
// Licensed 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 caddy

import (
	"context"
	"encoding/json"
	"io"
	"testing"
)

func TestContextWithValuePreservesMetricsRegistry(t *testing.T) {
	ctx, cancel := NewContext(Context{Context: context.Background()})
	t.Cleanup(cancel)

	reg := ctx.GetMetricsRegistry()
	if reg == nil {
		t.Fatal("expected a metrics registry on the base context")
	}

	type testKey struct{}
	derived := ctx.WithValue(testKey{}, "value")
	if got := derived.GetMetricsRegistry(); got != reg {
		t.Fatalf("WithValue must preserve the metrics registry: got %p, want %p", got, reg)
	}
}

func ExampleContext_LoadModule() {
	// this whole first part is just setting up for the example;
	// note the struct tags - very important; we specify inline_key
	// because that is the only way to know the module name
	var ctx Context
	myStruct := &struct {
		// This godoc comment will appear in module documentation.
		GuestModuleRaw json.RawMessage `json:"guest_module,omitempty" caddy:"namespace=example inline_key=name"`

		// this is where the decoded module will be stored; in this
		// example, we pretend we need an io.Writer but it can be
		// any interface type that is useful to you
		guestModule io.Writer
	}{
		GuestModuleRaw: json.RawMessage(`{"name":"module_name","foo":"bar"}`),
	}

	// if a guest module is provided, we can load it easily
	if myStruct.GuestModuleRaw != nil {
		mod, err := ctx.LoadModule(myStruct, "GuestModuleRaw")
		if err != nil {
			// you'd want to actually handle the error here
			// return fmt.Errorf("loading guest module: %v", err)
		}
		// mod contains the loaded and provisioned module,
		// it is now ready for us to use
		myStruct.guestModule = mod.(io.Writer)
	}

	// use myStruct.guestModule from now on
}

func ExampleContext_LoadModule_array() {
	// this whole first part is just setting up for the example;
	// note the struct tags - very important; we specify inline_key
	// because that is the only way to know the module name
	var ctx Context
	myStruct := &struct {
		// This godoc comment will appear in module documentation.
		GuestModulesRaw []json.RawMessage `json:"guest_modules,omitempty" caddy:"namespace=example inline_key=name"`

		// this is where the decoded module will be stored; in this
		// example, we pretend we need an io.Writer but it can be
		// any interface type that is useful to you
		guestModules []io.Writer
	}{
		GuestModulesRaw: []json.RawMessage{
			json.RawMessage(`{"name":"module1_name","foo":"bar1"}`),
			json.RawMessage(`{"name":"module2_name","foo":"bar2"}`),
		},
	}

	// since our input is []json.RawMessage, the output will be []any
	mods, err := ctx.LoadModule(myStruct, "GuestModulesRaw")
	if err != nil {
		// you'd want to actually handle the error here
		// return fmt.Errorf("loading guest modules: %v", err)
	}
	for _, mod := range mods.([]any) {
		myStruct.guestModules = append(myStruct.guestModules, mod.(io.Writer))
	}

	// use myStruct.guestModules from now on
}

func ExampleContext_LoadModule_map() {
	// this whole first part is just setting up for the example;
	// note the struct tags - very important; we don't specify
	// inline_key because the map key is the module name
	var ctx Context
	myStruct := &struct {
		// This godoc comment will appear in module documentation.
		GuestModulesRaw ModuleMap `json:"guest_modules,omitempty" caddy:"namespace=example"`

		// this is where the decoded module will be stored; in this
		// example, we pretend we need an io.Writer but it can be
		// any interface type that is useful to you
		guestModules map[string]io.Writer
	}{
		GuestModulesRaw: ModuleMap{
			"module1_name": json.RawMessage(`{"foo":"bar1"}`),
			"module2_name": json.RawMessage(`{"foo":"bar2"}`),
		},
	}

	// since our input is map[string]json.RawMessage, the output will be map[string]any
	mods, err := ctx.LoadModule(myStruct, "GuestModulesRaw")
	if err != nil {
		// you'd want to actually handle the error here
		// return fmt.Errorf("loading guest modules: %v", err)
	}
	for modName, mod := range mods.(map[string]any) {
		myStruct.guestModules[modName] = mod.(io.Writer)
	}

	// use myStruct.guestModules from now on
}