stdout_logger.go

Documentation: google.golang.org/grpc/authz/audit/stdout

     1  /*
     2   *
     3   * Copyright 2023 gRPC authors.
     4   *
     5   * Licensed under the Apache License, Version 2.0 (the "License");
     6   * you may not use this file except in compliance with the License.
     7   * You may obtain a copy of the License at
     8   *
     9   *     http://www.apache.org/licenses/LICENSE-2.0
    10   *
    11   * Unless required by applicable law or agreed to in writing, software
    12   * distributed under the License is distributed on an "AS IS" BASIS,
    13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14   * See the License for the specific language governing permissions and
    15   * limitations under the License.
    16   *
    17   */
    18  
    19  // Package stdout defines an stdout audit logger.
    20  package stdout
    21  
    22  import (
    23  	"encoding/json"
    24  	"log"
    25  	"os"
    26  	"time"
    27  
    28  	"google.golang.org/grpc/authz/audit"
    29  	"google.golang.org/grpc/grpclog"
    30  )
    31  
    32  var grpcLogger = grpclog.Component("authz-audit")
    33  
    34  // Name is the string to identify this logger type in the registry
    35  const Name = "stdout_logger"
    36  
    37  func init() {
    38  	audit.RegisterLoggerBuilder(&loggerBuilder{
    39  		goLogger: log.New(os.Stdout, "", 0),
    40  	})
    41  }
    42  
    43  type event struct {
    44  	FullMethodName string `json:"rpc_method"`
    45  	Principal      string `json:"principal"`
    46  	PolicyName     string `json:"policy_name"`
    47  	MatchedRule    string `json:"matched_rule"`
    48  	Authorized     bool   `json:"authorized"`
    49  	Timestamp      string `json:"timestamp"` // Time when the audit event is logged via Log method
    50  }
    51  
    52  // logger implements the audit.logger interface by logging to standard output.
    53  type logger struct {
    54  	goLogger *log.Logger
    55  }
    56  
    57  // Log marshals the audit.Event to json and prints it to standard output.
    58  func (l *logger) Log(event *audit.Event) {
    59  	jsonContainer := map[string]any{
    60  		"grpc_audit_log": convertEvent(event),
    61  	}
    62  	jsonBytes, err := json.Marshal(jsonContainer)
    63  	if err != nil {
    64  		grpcLogger.Errorf("failed to marshal AuditEvent data to JSON: %v", err)
    65  		return
    66  	}
    67  	l.goLogger.Println(string(jsonBytes))
    68  }
    69  
    70  // loggerConfig represents the configuration for the stdout logger.
    71  // It is currently empty and implements the audit.Logger interface by embedding it.
    72  type loggerConfig struct {
    73  	audit.LoggerConfig
    74  }
    75  
    76  type loggerBuilder struct {
    77  	goLogger *log.Logger
    78  }
    79  
    80  func (loggerBuilder) Name() string {
    81  	return Name
    82  }
    83  
    84  // Build returns a new instance of the stdout logger.
    85  // Passed in configuration is ignored as the stdout logger does not
    86  // expect any configuration to be provided.
    87  func (lb *loggerBuilder) Build(audit.LoggerConfig) audit.Logger {
    88  	return &logger{
    89  		goLogger: lb.goLogger,
    90  	}
    91  }
    92  
    93  // ParseLoggerConfig is a no-op since the stdout logger does not accept any configuration.
    94  func (*loggerBuilder) ParseLoggerConfig(config json.RawMessage) (audit.LoggerConfig, error) {
    95  	if len(config) != 0 && string(config) != "{}" {
    96  		grpcLogger.Warningf("Stdout logger doesn't support custom configs. Ignoring:\n%s", string(config))
    97  	}
    98  	return &loggerConfig{}, nil
    99  }
   100  
   101  func convertEvent(auditEvent *audit.Event) *event {
   102  	return &event{
   103  		FullMethodName: auditEvent.FullMethodName,
   104  		Principal:      auditEvent.Principal,
   105  		PolicyName:     auditEvent.PolicyName,
   106  		MatchedRule:    auditEvent.MatchedRule,
   107  		Authorized:     auditEvent.Authorized,
   108  		Timestamp:      time.Now().Format(time.RFC3339Nano),
   109  	}
   110  }
   111
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