klevy-toast opened a new issue, #1429:
URL: https://github.com/apache/pulsar-client-go/issues/1429
When using the client to check a value on the namespace / topic that may be
either _unset_ or _set to 0_, there is no way to distinguish the two states,
which is misleading and incorrect. By contrast, the java pulsar admin client
shows `null` for an unset value and `0` for a value that is set to 0. This is
consequential because most of these settings appear on multiple layers - they
can be applied at the broker level, or namespace level, or topic level. Setting
them to `0` explicitly disables them and is different from an unset value,
which will then default to whatever is set at a higher level.
As far as I can tell, this applies to the following methods:
1. **GetNamespaceMessageTTL** / **GetNamespaceMessageTTLWithContext**
2. **GetMaxConsumersPerTopic** / **GetMaxConsumersPerTopicWithContext**
3. **GetMaxProducersPerTopic** / **GetMaxProducersPerTopicWithContext**
4. **GetMaxConsumersPerSubscription** /
**GetMaxConsumersPerSubscriptionWithContext**
5. **GetMaxTopicsPerNamespace** / **GetMaxTopicsPerNamespaceWithContext**
6. **GetOffloadThreshold** / **GetOffloadThresholdWithContext**
7. **GetOffloadThresholdInSeconds** /
**GetOffloadThresholdInSecondsWithContext**
8. **GetOffloadDeleteLag** / **GetOffloadDeleteLagWithContext**
9. **GetCompactionThreshold** / **GetCompactionThresholdWithContext**
#### Topic Admin Methods (18 methods)
1. **GetMessageTTL** / **GetMessageTTLWithContext**
2. **GetMaxProducers** / **GetMaxProducersWithContext**
3. **GetMaxConsumers** / **GetMaxConsumersWithContext**
4. **GetMaxUnackMessagesPerConsumer** /
**GetMaxUnackMessagesPerConsumerWithContext**
5. **GetMaxUnackMessagesPerSubscription** /
**GetMaxUnackMessagesPerSubscriptionWithContext**
6. **GetCompactionThreshold** / **GetCompactionThresholdWithContext**
7. **GetMaxConsumersPerSubscription** /
**GetMaxConsumersPerSubscriptionWithContext**
8. **GetMaxMessageSize** / **GetMaxMessageSizeWithContext**
9. **GetMaxSubscriptionsPerTopic** /
**GetMaxSubscriptionsPerTopicWithContext**
10. **GetDeduplicationSnapshotInterval** /
**GetDeduplicationSnapshotIntervalWithContext**
#### Expected behavior
Since the `int` type is used, we should use a sentinel value of -1 to
signify that the value is not actually set.
#### Actual behavior
An empty response is unmarshalled as 0.
#### Steps to reproduce
Example for topics - getMaxConsumers
```
package main
import (
"fmt"
"log"
"os"
"github.com/apache/pulsar-client-go/pulsaradmin"
"github.com/apache/pulsar-client-go/pulsaradmin/pkg/utils"
)
func main() {
topic := "persistent://public/default/test-topic"
if len(os.Args) > 1 {
topic = os.Args[1]
}
webServiceURL := os.Getenv("PULSAR_WEB_SERVICE_URL")
if webServiceURL == "" {
webServiceURL = "http://localhost:8080";
}
cfg := &pulsaradmin.Config{
WebServiceURL: webServiceURL,
}
if token := os.Getenv("PULSAR_AUTH_TOKEN"); token != "" {
cfg.Token = token
}
client, err := pulsaradmin.NewClient(cfg)
if err != nil {
log.Fatalf("Failed to create client: %v", err)
}
topicName, err := utils.GetTopicName(topic)
if err != nil {
log.Fatalf("Failed to parse topic: %v", err)
}
fmt.Printf("Topic: %s\n\n", topic)
// Create topic
client.Topics().Create(*topicName, 0)
// Initial value
val, _ := client.Topics().GetMaxConsumers(*topicName)
fmt.Printf("Initial: %d\n", val)
// Set to 0
err = client.Topics().SetMaxConsumers(*topicName, 0)
if err != nil {
log.Fatalf("Set failed: %v", err)
}
val, _ = client.Topics().GetMaxConsumers(*topicName)
fmt.Printf("After set to 0: %d\n", val)
// Remove
err = client.Topics().RemoveMaxConsumers(*topicName)
if err != nil {
log.Fatalf("Remove failed: %v", err)
}
val, _ = client.Topics().GetMaxConsumers(*topicName)
fmt.Printf("After remove: %d\n", val)
fmt.Println("\nResult: Topic API always returns 0, cannot distinguish
between unset/0/removed")
}
```
#### System configuration
**Pulsar version**: 4.x but applies to all
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