MM-16822 - Implement KVSetWithOptions (#11818)

* Add SetWithOptions

* Avoid passing two structs to the functions

* Rename ExpiryInSeconds -> ExpireInSeconds

* Use t.Run for the tests

* Fix build

* Address feedback

* Update log message

* Update docs and use KVSetWithOptions in KVCompareAndSetJSON

* Improve code style

* Use struct instead of pointer to struct

* Fix minimum server versions

* Update documentation

* Address feedback

* Revert new implemention of kv helpers

* Adress feedback

model/plugin_kvset_options.go

@@ -0,0 +1,77 @@
+// Copyright (c) 2017-present Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package model
+
+import (
+	"encoding/json"
+	"net/http"
+)
+
+// PluginKVSetOptions contains information on how to store a value in the plugin KV store.
+type PluginKVSetOptions struct {
+	EncodeJSON      bool        // If true, store the JSON encoding of newValue
+	Atomic          bool        // Only store the value if the current value matches the oldValue
+	OldValue        interface{} // The value to compare with the current value. Only used when Atomic is true
+	ExpireInSeconds int64       // Set an expire counter
+}
+
+// IsValid returns nil if the chosen options are valid.
+func (opt *PluginKVSetOptions) IsValid() *AppError {
+	if !opt.Atomic && opt.OldValue != nil {
+		return NewAppError(
+			"PluginKVSetOptions.IsValid",
+			"model.plugin_kvset_options.is_valid.old_value.app_error",
+			nil,
+			"",
+			http.StatusBadRequest,
+		)
+	}
+
+	return nil
+}
+
+// GetOldValueSerialized returns the serialized old value either as directly
+// or encoded as JSON depending on the chosen options.
+func (opt *PluginKVSetOptions) GetOldValueSerialized() ([]byte, *AppError) {
+	return opt.serializeValue(opt.OldValue)
+}
+
+func (opt *PluginKVSetOptions) serializeValue(value interface{}) ([]byte, *AppError) {
+	if opt.EncodeJSON {
+		data, err := json.Marshal(value)
+		if err != nil {
+			return nil, NewAppError("PluginKVSetOptions.serializeValue", "model.plugin_kvset_options.serialize_value.app_error", map[string]interface{}{"EncodeJSON": opt.EncodeJSON}, "Could not serialize JSON value", http.StatusBadRequest)
+		}
+		return data, nil
+	}
+
+	castResult, ok := value.([]byte)
+	if !ok {
+		return nil, NewAppError("PluginKVSetOptions.SerializeValue", "model.plugin_kvset_options.serialize_value.app_error", map[string]interface{}{"EncodeJSON": opt.EncodeJSON}, "Could not cast value to []byte", http.StatusBadRequest)
+	}
+
+	return castResult, nil
+}
+
+// NewPluginKeyValueFromOptions return a PluginKeyValue given a pluginID, a KV pair and options.
+func NewPluginKeyValueFromOptions(pluginId, key string, value interface{}, opt PluginKVSetOptions) (*PluginKeyValue, *AppError) {
+	serializedValue, err := opt.serializeValue(value)
+	if err != nil {
+		return nil, err
+	}
+
+	expireAt := int64(0)
+	if opt.ExpireInSeconds > 0 {
+		expireAt = GetMillis() + (opt.ExpireInSeconds * 1000)
+	}
+
+	kv := &PluginKeyValue{
+		PluginId: pluginId,
+		Key:      key,
+		Value:    serializedValue,
+		ExpireAt: expireAt,
+	}
+
+	return kv, nil
+}