| // Copyright (c) 2016 Uber Technologies, Inc. |
| // |
| // Permission is hereby granted, free of charge, to any person obtaining a copy |
| // of this software and associated documentation files (the "Software"), to deal |
| // in the Software without restriction, including without limitation the rights |
| // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| // copies of the Software, and to permit persons to whom the Software is |
| // furnished to do so, subject to the following conditions: |
| // |
| // The above copyright notice and this permission notice shall be included in |
| // all copies or substantial portions of the Software. |
| // |
| // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
| // THE SOFTWARE. |
| |
| package zapcore |
| |
| import "go.uber.org/multierr" |
| |
| type hooked struct { |
| Core |
| funcs []func(Entry) error |
| } |
| |
| // RegisterHooks wraps a Core and runs a collection of user-defined callback |
| // hooks each time a message is logged. Execution of the callbacks is blocking. |
| // |
| // This offers users an easy way to register simple callbacks (e.g., metrics |
| // collection) without implementing the full Core interface. |
| func RegisterHooks(core Core, hooks ...func(Entry) error) Core { |
| funcs := append([]func(Entry) error{}, hooks...) |
| return &hooked{ |
| Core: core, |
| funcs: funcs, |
| } |
| } |
| |
| func (h *hooked) Check(ent Entry, ce *CheckedEntry) *CheckedEntry { |
| // Let the wrapped Core decide whether to log this message or not. This |
| // also gives the downstream a chance to register itself directly with the |
| // CheckedEntry. |
| if downstream := h.Core.Check(ent, ce); downstream != nil { |
| return downstream.AddCore(ent, h) |
| } |
| return ce |
| } |
| |
| func (h *hooked) With(fields []Field) Core { |
| return &hooked{ |
| Core: h.Core.With(fields), |
| funcs: h.funcs, |
| } |
| } |
| |
| func (h *hooked) Write(ent Entry, _ []Field) error { |
| // Since our downstream had a chance to register itself directly with the |
| // CheckedMessage, we don't need to call it here. |
| var err error |
| for i := range h.funcs { |
| err = multierr.Append(err, h.funcs[i](ent)) |
| } |
| return err |
| } |