pick: #38489
Usage:
1. `curl http://be_ip:be_host/api/compaction_score?top_n=10` Returns a
json object contains compaction score for top n, n=top_n.
```
[
{
"compaction_score": "5",
"tablet_id": "42595"
},
{
"compaction_score": "5",
"tablet_id": "42587"
},
{
"compaction_score": "5",
"tablet_id": "42593"
},
{
"compaction_score": "5",
"tablet_id": "42597"
},
{
"compaction_score": "5",
"tablet_id": "42589"
},
{
"compaction_score": "5",
"tablet_id": "42599"
},
{
"compaction_score": "5",
"tablet_id": "42601"
},
{
"compaction_score": "5",
"tablet_id": "42591"
},
{
"compaction_score": "5",
"tablet_id": "42585"
},
{
"compaction_score": "4",
"tablet_id": "10034"
}
]
```
If top_n is not specified, return all compaction score for all tablets.
If top_n is illegal, raise an error.
```
invalid argument: top_n=wrong
```
2. `curl http://be_ip:be_host/api/compaction_score?sync_meta=true`
`sync_meta` is only available on cloud mode, will sync meta from meta
service. It can cooperate with top_n.
If add param `sync_meta` on non-cloud mode, will raise an error.
```
sync meta is only available for cloud mode
```
3. In the future, this endpoint may extend other utility, like fetching
tablet compaction score by table id, etc.
## Proposed changes
Issue Number: close #xxx
<!--Describe your changes.-->
d1d52ae68c