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authorMatthew Holt <[email protected]>2019-12-10 14:06:35 -0700
committerMatthew Holt <[email protected]>2019-12-10 14:06:35 -0700
commitfab5e4372a941ee4259adea9295f49dcadca26a4 (patch)
treef86b3f0d5da925ca1df9b641dcc9f6727c15ee4a
parent3c90e370a49cafe7f58c7195187822ddc86ced4a (diff)
downloadcaddy-fab5e4372a941ee4259adea9295f49dcadca26a4.tar.gz
caddy-fab5e4372a941ee4259adea9295f49dcadca26a4.zip
core: Add godoc examples for LoadModule
-rw-r--r--context.go4
-rw-r--r--context_test.go118
2 files changed, 121 insertions, 1 deletions
diff --git a/context.go b/context.go
index c95b08f51..e515cb975 100644
--- a/context.go
+++ b/context.go
@@ -124,7 +124,9 @@ func (ctx *Context) OnCancel(f func()) {
// and store them on the same struct. Storing them on the same struct makes for
// easy garbage collection when your host module is no longer needed.
//
-// Loaded modules have already been provisioned and validated.
+// Loaded modules have already been provisioned and validated. Upon returning
+// successfully, this method clears the json.RawMessage(s) in the field since
+// the raw JSON is no longer needed, and this allows the GC to free up memory.
func (ctx Context) LoadModule(structPointer interface{}, fieldName string) (interface{}, error) {
val := reflect.ValueOf(structPointer).Elem().FieldByName(fieldName)
typ := val.Type()
diff --git a/context_test.go b/context_test.go
new file mode 100644
index 000000000..afa10dbd0
--- /dev/null
+++ b/context_test.go
@@ -0,0 +1,118 @@
+// 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 (
+ "encoding/json"
+ "io"
+)
+
+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 []interface{}
+ 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.([]interface{}) {
+ 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]interface{}
+ 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]interface{}) {
+ myStruct.guestModules[modName] = mod.(io.Writer)
+ }
+
+ // use myStruct.guestModules from now on
+}