github.com/cloud-foundations/dominator@v0.0.0-20221004181915-6e4fee580046/cmd/vm-control/traceMetadata.go (about)

     1  package main
     2  
     3  import (
     4  	"errors"
     5  	"fmt"
     6  	"net"
     7  
     8  	"github.com/Cloud-Foundations/Dominator/lib/log"
     9  	"github.com/Cloud-Foundations/Dominator/lib/srpc"
    10  	proto "github.com/Cloud-Foundations/Dominator/proto/hypervisor"
    11  )
    12  
    13  func traceVmMetadataSubcommand(args []string, logger log.DebugLogger) error {
    14  	if err := traceVmMetadata(args[0], logger); err != nil {
    15  		return fmt.Errorf("Error tracing VM metadata: %s", err)
    16  	}
    17  	return nil
    18  }
    19  
    20  func traceVmMetadata(vmHostname string, logger log.DebugLogger) error {
    21  	if vmIP, hypervisor, err := lookupVmAndHypervisor(vmHostname); err != nil {
    22  		return err
    23  	} else {
    24  		return traceVmMetadataOnHypervisor(hypervisor, vmIP, logger)
    25  	}
    26  }
    27  
    28  func traceVmMetadataOnHypervisor(hypervisor string, ipAddr net.IP,
    29  	logger log.DebugLogger) error {
    30  	client, err := dialHypervisor(hypervisor)
    31  	if err != nil {
    32  		return err
    33  	}
    34  	defer client.Close()
    35  	return doTraceMetadata(client, ipAddr, logger)
    36  }
    37  
    38  func doTraceMetadata(client *srpc.Client, ipAddr net.IP,
    39  	logger log.Logger) error {
    40  	request := proto.TraceVmMetadataRequest{ipAddr}
    41  	conn, err := client.Call("Hypervisor.TraceVmMetadata")
    42  	if err != nil {
    43  		return err
    44  	}
    45  	defer conn.Close()
    46  	if err := conn.Encode(request); err != nil {
    47  		return err
    48  	}
    49  	if err := conn.Flush(); err != nil {
    50  		return err
    51  	}
    52  	var reply proto.TraceVmMetadataResponse
    53  	if err := conn.Decode(&reply); err != nil {
    54  		return err
    55  	}
    56  	if reply.Error != "" {
    57  		return errors.New(reply.Error)
    58  	}
    59  	for {
    60  		if line, err := conn.ReadString('\n'); err != nil {
    61  			return err
    62  		} else {
    63  			if line == "\n" {
    64  				return nil
    65  			}
    66  			logger.Print(line)
    67  		}
    68  	}
    69  }
    70  
    71  func maybeWatchVm(client *srpc.Client, hypervisor string, ipAddr net.IP,
    72  	logger log.DebugLogger) error {
    73  	if !*traceMetadata && *probePortNum < 1 {
    74  		return nil
    75  	} else if *traceMetadata && *probePortNum < 1 {
    76  		return doTraceMetadata(client, ipAddr, logger)
    77  	} else if !*traceMetadata && *probePortNum > 0 {
    78  		return probeVmPortOnHypervisorClient(client, ipAddr, logger)
    79  	} else { // Do both.
    80  		go doTraceMetadata(client, ipAddr, logger)
    81  		return probeVmPortOnHypervisor(hypervisor, ipAddr, logger)
    82  	}
    83  }