go.temporal.io/server@v1.23.0/common/dynamicconfig/client.go (about)

     1  // The MIT License
     2  //
     3  // Copyright (c) 2020 Temporal Technologies Inc.  All rights reserved.
     4  //
     5  // Copyright (c) 2020 Uber Technologies, Inc.
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     7  // Permission is hereby granted, free of charge, to any person obtaining a copy
     8  // of this software and associated documentation files (the "Software"), to deal
     9  // in the Software without restriction, including without limitation the rights
    10  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    11  // copies of the Software, and to permit persons to whom the Software is
    12  // furnished to do so, subject to the following conditions:
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    14  // The above copyright notice and this permission notice shall be included in
    15  // all copies or substantial portions of the Software.
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    17  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    18  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    19  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    20  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    21  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    22  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    23  // THE SOFTWARE.
    24  
    25  package dynamicconfig
    26  
    27  import (
    28  	enumspb "go.temporal.io/api/enums/v1"
    29  
    30  	enumsspb "go.temporal.io/server/api/enums/v1"
    31  )
    32  
    33  type (
    34  	// Client is a source of dynamic configuration. The default Client, fileBasedClient, reads
    35  	// from a file in the filesystem, and refreshes it periodically. You can extend the server
    36  	// with an alternate Client using ServerOptions.
    37  	Client interface {
    38  		// GetValue returns a set of values and associated constraints for a key. Not all
    39  		// constraints are valid for all keys.
    40  		//
    41  		// The returned slice of ConstrainedValues is treated as a set, and order does not
    42  		// matter. The effective order of constraints is determined by server logic. See the
    43  		// comment on Constraints below.
    44  		//
    45  		// If none of the ConstrainedValues match the constraints being used for the key, then
    46  		// the server default value will be used.
    47  		//
    48  		// Note that GetValue is called very often! You should not synchronously call out to an
    49  		// external system. Instead you should keep a set of all configured values, refresh it
    50  		// periodically or when notified, and only do in-memory lookups inside of GetValue.
    51  		GetValue(key Key) []ConstrainedValue
    52  	}
    53  
    54  	// Key is a key/property stored in dynamic config. For convenience, it is recommended that
    55  	// you treat keys as case-insensitive.
    56  	Key string
    57  
    58  	// ConstrainedValue is a value plus associated constraints.
    59  	//
    60  	// The type of the Value field depends on the key. Acceptable types will be one of:
    61  	//   int, float64, bool, string, map[string]any, time.Duration
    62  	//
    63  	// If time.Duration is expected, a string is also accepted, which will be converted using
    64  	// timestamp.ParseDurationDefaultDays. If float64 is expected, int is also accepted. In
    65  	// other cases, the exact type must be used. If a Value is returned with an unexpected
    66  	// type, it will be ignored.
    67  	ConstrainedValue struct {
    68  		Constraints Constraints
    69  		Value       any
    70  	}
    71  
    72  	// Constraints describe under what conditions a ConstrainedValue should be used.
    73  	// There are few standard "constraint precedence orders" that the server uses:
    74  	//   global precedence:
    75  	//     no constraints
    76  	//   namespace precedence:
    77  	//     Namespace
    78  	//     no constraints
    79  	//   task queue precedence
    80  	//     Namespace+TaskQueueName+TaskQueueType
    81  	//     Namespace+TaskQueueName
    82  	//     TaskQueueName
    83  	//     Namespace
    84  	//     no constraints
    85  	//   shard id precedence:
    86  	//     ShardID
    87  	//     no constraints
    88  	// In each case, the constraints that the server is checking and the constraints that apply
    89  	// to the value must match exactly, including the fields that are not set (zero values).
    90  	// That is, for keys that use namespace precedence, you must either return a
    91  	// ConstrainedValue with only Namespace set, or with no fields set. (Or return one of
    92  	// each.) If you return a ConstrainedValue with Namespace and ShardID set, for example,
    93  	// that value will never be used, even if the Namespace matches.
    94  	Constraints struct {
    95  		Namespace     string
    96  		NamespaceID   string
    97  		TaskQueueName string
    98  		TaskQueueType enumspb.TaskQueueType
    99  		ShardID       int32
   100  		TaskType      enumsspb.TaskType
   101  	}
   102  )