github.com/facebookincubator/go-belt@v0.0.0-20230703220935-39cd348f1a38/tool/logger/types/hook.go (about)

     1  // Copyright 2022 Meta Platforms, Inc. and affiliates.
     2  //
     3  // Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
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     5  // 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
     6  //
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     9  // 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
    10  //
    11  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
    12  
    13  package types
    14  
    15  import (
    16  	"github.com/facebookincubator/go-belt"
    17  	"github.com/facebookincubator/go-belt/pkg/field"
    18  )
    19  
    20  // Hook is a pre-processor for log entries.
    21  // It may for example modify them or cancel them.
    22  type Hook interface {
    23  	// ProcessLogEntry is called right before sending the Entry to a Emitter.
    24  	//
    25  	// If the returned value is false, then the sending and processing by other hooks
    26  	// are cancelled.
    27  	//
    28  	// It is allowed to modify the entry.
    29  	ProcessLogEntry(*Entry) bool
    30  
    31  	// Flush gracefully empties any buffers the hook may have.
    32  	Flush()
    33  }
    34  
    35  // Hooks is a collection of Hook-s.
    36  type Hooks []Hook
    37  
    38  var _ Hook = (Hooks)(nil)
    39  
    40  // ProcessLogEntry implements Hook.
    41  func (s Hooks) ProcessLogEntry(e *Entry) bool {
    42  	for _, hook := range s {
    43  		if !hook.ProcessLogEntry(e) {
    44  			return false
    45  		}
    46  	}
    47  	return true
    48  }
    49  
    50  // Flush implements Hook.
    51  func (s Hooks) Flush() {
    52  	for _, hook := range s {
    53  		hook.Flush()
    54  	}
    55  }
    56  
    57  // PreHookResult is a result of computations returned by a PreHook.
    58  type PreHookResult struct {
    59  	// Skip forces a Logger to do not log this Entry.
    60  	Skip bool
    61  
    62  	// ExtraFields adds additional fields to the Entry.
    63  	ExtraFields field.AbstractFields
    64  
    65  	// ExtraEntryProperties adds additional Entry.Properties.
    66  	ExtraEntryProperties EntryProperties
    67  }
    68  
    69  // PreHook is executed very early in a Logger, allowing to discard or change
    70  // an Entry before any essential computations are done.
    71  //
    72  // For example it may be useful for samplers.
    73  type PreHook interface {
    74  	// ProcessInput is executed when functions Log, Trace, Debug, Info, Warn, Error, Panic and Fatal are called.
    75  	//
    76  	// TraceIDs are provided by Logger/CompactLogger and the rest arguments are just passed-through.
    77  	ProcessInput(belt.TraceIDs, Level, ...any) PreHookResult
    78  
    79  	// ProcessInputf is executed when functions Logf, Tracef, Debugf, Infof, Warnf, Errorf, Panicf and Fatalf are called.
    80  	//
    81  	// TraceIDs are provided by Logger/CompactLogger and the rest arguments are just passed-through.
    82  	ProcessInputf(belt.TraceIDs, Level, string, ...any) PreHookResult
    83  
    84  	// ProcessInputf is executed when functions LogFields, TraceFields, DebugFields, InfoFields, WarnFields, ErrorFields, PanicFields and FatalFields are called.
    85  	//
    86  	// TraceIDs are provided by Logger/CompactLogger and the rest arguments are just passed-through.
    87  	ProcessInputFields(belt.TraceIDs, Level, string, field.AbstractFields) PreHookResult
    88  }
    89  
    90  // PreHooks is a collection of PreHook-s.
    91  type PreHooks []PreHook
    92  
    93  var _ PreHook = (PreHooks)(nil)
    94  
    95  // ProcessInput implements PreHook.
    96  func (s PreHooks) ProcessInput(traceIDs belt.TraceIDs, level Level, values ...any) PreHookResult {
    97  	var result PreHookResult
    98  	for _, hook := range s {
    99  		oneResult := hook.ProcessInput(traceIDs, level, values...)
   100  		result.Skip = oneResult.Skip
   101  		if result.Skip {
   102  			return result
   103  		}
   104  		result.ExtraEntryProperties = append(result.ExtraEntryProperties, oneResult.ExtraEntryProperties)
   105  		result.ExtraFields = field.Add(result.ExtraFields, oneResult.ExtraFields)
   106  	}
   107  
   108  	return result
   109  }
   110  
   111  // ProcessInputf implements PreHook.
   112  func (s PreHooks) ProcessInputf(traceIDs belt.TraceIDs, level Level, format string, args ...any) PreHookResult {
   113  	var result PreHookResult
   114  	for _, hook := range s {
   115  		oneResult := hook.ProcessInputf(traceIDs, level, format, args...)
   116  		result.Skip = oneResult.Skip
   117  		if result.Skip {
   118  			return result
   119  		}
   120  		result.ExtraEntryProperties = append(result.ExtraEntryProperties, oneResult.ExtraEntryProperties)
   121  		result.ExtraFields = field.Add(result.ExtraFields, oneResult.ExtraFields)
   122  	}
   123  
   124  	return result
   125  }
   126  
   127  // ProcessInputFields implements PreHook.
   128  func (s PreHooks) ProcessInputFields(traceIDs belt.TraceIDs, level Level, message string, addFields field.AbstractFields) PreHookResult {
   129  	var result PreHookResult
   130  	for _, hook := range s {
   131  		oneResult := hook.ProcessInputFields(traceIDs, level, message, addFields)
   132  		result.Skip = oneResult.Skip
   133  		if result.Skip {
   134  			return result
   135  		}
   136  		result.ExtraEntryProperties = append(result.ExtraEntryProperties, oneResult.ExtraEntryProperties)
   137  		result.ExtraFields = field.Add(result.ExtraFields, oneResult.ExtraFields)
   138  	}
   139  
   140  	return result
   141  }