Date: Tue, 21 Jul 2020 00:36:14 GMT
```

### Checking cluster health for maintenance

You may query the cluster probe endpoint to check if the node which received the request can be taken down for maintenance, if the server replies back '412 Precondition Failed' this means you will lose HA. '200 OK' means you are okay to proceed.

```
curl http://minio1:9001/minio/health/cluster?maintenance=true
HTTP/1.1 412 Precondition Failed
Accept-Ranges: bytes

  const resp = await github.rest.issues.create({
    owner,
    repo,
    assignees: assignee_logins,
    title: `Issue created for Rollback of PR #${pr_number}: ${pr_title}`,
    body: `Merged PR #${pr_number} is rolled back in ${rollback_commit}.
    Please follow up with the reviewer and close this issue once its resolved.`
  });
  return `Issue created: ${resp.data.number} with Title: ${resp.data.title}`;

metadata changes to source object version. If active-active replication is configured, any incoming uploads and metadata changes to versions created on the target, will sync back to the source and be marked as `REPLICA` on the source. AWS, as well as MinIO do not by default sync metadata changes on a object version marked `REPLICA` back to source. This requires a setting in the replication configuration called [replica modification sync](https://aws.amazon.com/about-aws/whats-new/2020/12/amazon-s3-rep...

            alternatingKeysAndValues[previousKeyIndex ^ 1] = value;
            continue entries;
          }
        }
        if (outI < i) { // if outI == i don't bother writing the values back where they came from
          alternatingKeysAndValues[outKeyIndex] = key;
          alternatingKeysAndValues[outKeyIndex ^ 1] = value;
        }
        outI++;
      }

		if tok.ScanToken == scanner.EOF {
			p.errorf("missing right parenthesis")
			return
		}
		rname := tok.String()
		p.back()
		haveConstant = !p.atStartOfRegister(rname)
		if !haveConstant {
			p.back() // Put back the '('.
		}
	}
	if haveConstant {
		p.back()
		if p.have(scanner.Float) {
			if prefix != '$' {
				p.errorf("floating-point constant must be an immediate")
			}

The process that happens when your API app calls the *external API* is named a "callback". Because the software that the external developer wrote sends a request to your API and then your API *calls back*, sending a request to an *external API* (that was probably created by the same developer).

/// tip

The *path operation* for `swagger_ui_redirect` is a helper for when you use OAuth2.

If you integrate your API with an OAuth2 provider, you will be able to authenticate and come back to the API docs with the acquired credentials. And interact with it using the real OAuth2 authentication.

Swagger UI will handle it behind the scenes for you, but it needs this "redirect" helper.

///

    @Override
    public Logger getLogger() {
        return logger;
    }

    /**
     * Gets the appropriate extractor for the given response data.
     * Selects an extractor based on the MIME type or falls back to the Tika extractor.
     *
     * @param responseData the response data containing the document to extract
     * @return the extractor instance for processing the document

  /**
   * Returns an optional enum constant for the given type, using {@link Enum#valueOf}. If the
   * constant does not exist, {@link Optional#absent} is returned. A common use case is for parsing
   * user input or falling back to a default enum constant. For example, {@code
   * Enums.getIfPresent(Country.class, countryInput).or(Country.DEFAULT);}
   *
   * @since 12.0
   */

				break
			}

			logger(
				context.Background(),
				fmt.Errorf("unable to send log entry to '%s' err '%w'", target.Name(), err),
				target.Name(),
			)

			select {
			// Retrying after 3secs back-off
			case <-retryTicker.C:
			case <-doneCh:
				return false
			}
		}
		return true
	}

	for {
		select {
		case key, ok := <-keyCh:
			if !ok {
				return
			}