divyadesai | 1900913 | 2020-03-04 12:58:08 +0000 | [diff] [blame] | 1 | // Copyright (c) 2016 Uber Technologies, Inc. |
| 2 | // |
| 3 | // Permission is hereby granted, free of charge, to any person obtaining a copy |
| 4 | // of this software and associated documentation files (the "Software"), to deal |
| 5 | // in the Software without restriction, including without limitation the rights |
| 6 | // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| 7 | // copies of the Software, and to permit persons to whom the Software is |
| 8 | // furnished to do so, subject to the following conditions: |
| 9 | // |
| 10 | // The above copyright notice and this permission notice shall be included in |
| 11 | // all copies or substantial portions of the Software. |
| 12 | // |
| 13 | // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| 14 | // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| 15 | // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| 16 | // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| 17 | // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| 18 | // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
| 19 | // THE SOFTWARE. |
| 20 | |
| 21 | package zapcore |
| 22 | |
| 23 | import "go.uber.org/multierr" |
| 24 | |
| 25 | type hooked struct { |
| 26 | Core |
| 27 | funcs []func(Entry) error |
| 28 | } |
| 29 | |
| 30 | // RegisterHooks wraps a Core and runs a collection of user-defined callback |
| 31 | // hooks each time a message is logged. Execution of the callbacks is blocking. |
| 32 | // |
| 33 | // This offers users an easy way to register simple callbacks (e.g., metrics |
| 34 | // collection) without implementing the full Core interface. |
| 35 | func RegisterHooks(core Core, hooks ...func(Entry) error) Core { |
| 36 | funcs := append([]func(Entry) error{}, hooks...) |
| 37 | return &hooked{ |
| 38 | Core: core, |
| 39 | funcs: funcs, |
| 40 | } |
| 41 | } |
| 42 | |
| 43 | func (h *hooked) Check(ent Entry, ce *CheckedEntry) *CheckedEntry { |
| 44 | // Let the wrapped Core decide whether to log this message or not. This |
| 45 | // also gives the downstream a chance to register itself directly with the |
| 46 | // CheckedEntry. |
| 47 | if downstream := h.Core.Check(ent, ce); downstream != nil { |
| 48 | return downstream.AddCore(ent, h) |
| 49 | } |
| 50 | return ce |
| 51 | } |
| 52 | |
| 53 | func (h *hooked) With(fields []Field) Core { |
| 54 | return &hooked{ |
| 55 | Core: h.Core.With(fields), |
| 56 | funcs: h.funcs, |
| 57 | } |
| 58 | } |
| 59 | |
| 60 | func (h *hooked) Write(ent Entry, _ []Field) error { |
| 61 | // Since our downstream had a chance to register itself directly with the |
| 62 | // CheckedMessage, we don't need to call it here. |
| 63 | var err error |
| 64 | for i := range h.funcs { |
| 65 | err = multierr.Append(err, h.funcs[i](ent)) |
| 66 | } |
| 67 | return err |
| 68 | } |