Exception handling

The Go language uses the error type to identify errors. CSN supports two types of errors as shown in the table below:

When users invoke CSN-related APIs through the SDK, the required results will be returned along with any errors that occur. Users can retrieve and handle these errors. An example is provided below:

1args := &ListInstanceRequest{
2    InstanceType: "eip",
3}
4result, err := CsnClient.ListInstance(args)
5if err != nil {
6	switch realErr := err.(type) {
7	case *bce.BceClientError:
8		fmt.Println("client occurs error:", realErr.Error())
9	case *bce.BceServiceError:
10		fmt.Println("service occurs error:", realErr.Error())
11	default:
12		fmt.Println("unknown error:", err)
13	}
14}

Client exception

A client exception occurs when the client encounters issues while sending requests or transmitting data to CSN. For instance, if the network connection is unavailable during a request, a BceClientError will be returned.

Server exception

A server exception is generated when CSN server-side errors occur. The service returns detailed error messages to assist troubleshooting. For common server exceptions, refer to Dedicated Gateway Error Code

SDK logging

The CSN GO SDK has a logging module that supports six levels, three output destinations (standard output, standard error, file), and basic format settings. Its import path is github.com/baidubce/bce-sdk-go/util/log. When outputting to a file, it supports setting five log rolling modes (no rolling, rolling by day, rolling by hour, rolling by minute, rolling by size). In this case, the directory for output log files also needs to be set.

Default logging

The CSN GO SDK itself uses a package-level global log object, which does not record logs by default. If you need to output SDK-related logs, users must specify the output method and level by themselves. See the following examples for details:

1// import "github.com/baidubce/bce-sdk-go/util/log"
2 // Specify output to standard error, output INFO and above levels
3log.SetLogHandler(log.STDERR)
4log.SetLogLevel(log.INFO)
5 // Specify output to standard error and file, DEBUG and above levels, rolling by 1 GB file size
6log.SetLogHandler(log.STDERR | log.FILE)
7log.SetLogDir("/tmp/gosdk-log")
8log.SetRotateType(log.ROTATE_SIZE)
9log.SetRotateSize(1 << 30)
10 // Output to standard output, only output level and log message
11log.SetLogHandler(log.STDOUT)
12log.SetLogFormat([]string{log.FMT_LEVEL, log.FMT_MSG})

Description:

1. The default log output level is DEBUG
2. If set to output to a file, the default log output directory is /tmp, and it rolls by hour by default
3. If set to output to a file and roll by size, the default rolling size is 1 GB
4. The default log output format is: FMT_LEVEL, FMT_LTIME, FMT_LOCATION, FMT_MSG

Project usage

This logging module has no external dependencies. When users develop projects using the GO SDK, they can directly reference this logging module for use in their projects. Users can continue to use the package-level log object used by the GO SDK or create new log objects. See the following examples for details:

1// Directly use the package-level global log object (will be output together with the GO SDK’s own logs)
2log.SetLogHandler(log.STDERR)
3log.Debugf("%s", "logging message using the log package in the CSN go sdk")
4 // Create a new log object (output logs according to custom settings, separated from the GO SDK’s log output)
5myLogger := log.NewLogger()
6myLogger.SetLogHandler(log.FILE)
7myLogger.SetLogDir("/home/log")
8myLogger.SetRotateType(log.ROTATE_SIZE)
9myLogger.Info("this is my own logger from the CSN go sdk")