roachtest: surface cloud cluster spec info in artifacts for aws

This is a follow up PR to #124243.
It implements the surfacing of cluster specs for aws and refactors
logic in `cluster.go` to make it cloud agnostic.

Epic: none
Release note: None

pkg/cmd/roachtest/cluster.go

@@ -1394,7 +1394,7 @@ func (c *clusterImpl) FetchDebugZip(
 	})
 }
 
-// FetchVMSpecs downloads the VM specs from the cluster using `roachprod get`.
+// FetchVMSpecs saves the VM specs for each VM in the cluster.
 // The logs will be placed in the test's artifacts dir.
 func (c *clusterImpl) FetchVMSpecs(ctx context.Context, l *logger.Logger) error {
 	if c.IsLocal() {
@@ -1418,18 +1418,12 @@ func (c *clusterImpl) FetchVMSpecs(ctx context.Context, l *logger.Logger) error
 
 		for provider, vms := range providerToVMs {
 			p := vm.Providers[provider]
-			vmSpecs, err := p.GetVMSpecs(vms)
+			vmSpecs, err := p.GetVMSpecs(l, vms)
 			if err != nil {
 				l.Errorf("failed to get VM spec for provider %s: %s", provider, err)
 				continue
 			}
-			for _, vmSpec := range vmSpecs {
-				name, ok := vmSpec["name"].(string)
-				if !ok {
-					l.Errorf("failed to create spec files for VM\n%v", vmSpec)
-					continue
-				}
-
+			for name, vmSpec := range vmSpecs {
 				dest := filepath.Join(vmSpecsFolder, name+".json")
 				specJSON, err := json.MarshalIndent(vmSpec, "", "  ")
 				if err != nil {

pkg/roachprod/vm/aws/aws.go

@@ -18,6 +18,7 @@ import (
 	"math/rand"
 	"os"
 	"os/exec"
+	"slices"
 	"strconv"
 	"strings"
 	"time"
@@ -278,8 +279,61 @@ func (p *Provider) GetHostErrorVMs(
 	return nil, nil
 }
 
-func (p *Provider) GetVMSpecs(vms vm.List) ([]map[string]interface{}, error) {
-	return nil, nil
+// GetVMSpecs returns a map from VM.Name to a map of VM attributes, provided by AWS
+func (p *Provider) GetVMSpecs(
+	l *logger.Logger, vms vm.List,
+) (map[string]map[string]interface{}, error) {
+	if vms == nil {
+		return nil, errors.New("vms cannot be nil")
+	}
+
+	byRegion, err := regionMap(vms)
+	if err != nil {
+		return nil, err
+	}
+
+	// Extract the spec of all VMs and create a map from VM name to spec.
+	vmSpecs := make(map[string]map[string]interface{})
+	for region, list := range byRegion {
+		args := []string{
+			"ec2", "describe-instances",
+			"--region", region,
+			"--instance-ids",
+		}
+		args = append(args, list.ProviderIDs()...)
+		var describeInstancesResponse DescribeInstancesOutput
+		err := p.runJSONCommand(l, args, &describeInstancesResponse)
+		if err != nil {
+			return nil, errors.Wrapf(err, "error describing instances in region %s: ", region)
+		}
+		if len(describeInstancesResponse.Reservations) == 0 {
+			l.Errorf("failed to create spec files for instances in region %s: no Reservations found", region)
+			continue
+		}
+
+		for _, r := range describeInstancesResponse.Reservations {
+			for _, instance := range r.Instances {
+				i := slices.IndexFunc(instance.Tags, func(tag Tag) bool {
+					return tag.Key == "Name"
+				})
+				if i != -1 {
+					instanceRecord, err := json.MarshalIndent(instance, "", " ")
+					if err != nil {
+						l.Errorf("Failed to marshal JSON: %v for instance \n%v", err, instance)
+						continue
+					}
+					var vmSpec map[string]interface{}
+					err = json.Unmarshal(instanceRecord, &vmSpec)
+					if err != nil {
+						l.Errorf("Failed to unmarshal JSON: %v for instance record \n%v", err, instanceRecord)
+						continue
+					}
+					vmSpecs[instance.Tags[i].Value] = vmSpec
+				}
+			}
+		}
+	}
+	return vmSpecs, nil
 }
 
 const (

pkg/roachprod/vm/azure/azure.go

@@ -113,7 +113,9 @@ func (p *Provider) GetHostErrorVMs(
 	return nil, nil
 }
 
-func (p *Provider) GetVMSpecs(vms vm.List) ([]map[string]interface{}, error) {
+func (p *Provider) GetVMSpecs(
+	l *logger.Logger, vms vm.List,
+) (map[string]map[string]interface{}, error) {
 	return nil, nil
 }
 

pkg/roachprod/vm/flagstub/flagstub.go

@@ -48,7 +48,9 @@ func (p *provider) GetHostErrorVMs(
 	return nil, nil
 }
 
-func (p *provider) GetVMSpecs(vms vm.List) ([]map[string]interface{}, error) {
+func (p *provider) GetVMSpecs(
+	l *logger.Logger, vms vm.List,
+) (map[string]map[string]interface{}, error) {
 	return nil, nil
 }
 

pkg/roachprod/vm/gce/gcloud.go

@@ -400,16 +400,18 @@ func (p *Provider) GetHostErrorVMs(
 	return hostErrorVMs, nil
 }
 
-// GetVMSpecs returns a json list of VM specs, provided by GCE
-func (p *Provider) GetVMSpecs(vms vm.List) ([]map[string]interface{}, error) {
+// GetVMSpecs returns a map from VM.Name to a map of VM attributes, provided by GCE
+func (p *Provider) GetVMSpecs(
+	l *logger.Logger, vms vm.List,
+) (map[string]map[string]interface{}, error) {
 	if p.GetProject() == "" {
 		return nil, errors.New("project name cannot be empty")
 	}
 	if vms == nil {
 		return nil, errors.New("vms cannot be nil")
 	}
-	// Extract the spec of all VMs.
-	var vmSpecs []map[string]interface{}
+	// Extract the spec of all VMs and create a map from VM name to spec.
+	vmSpecs := make(map[string]map[string]interface{})
 	for _, vmInstance := range vms {
 		var vmSpec map[string]interface{}
 		vmFullResourceName := "projects/" + p.GetProject() + "/zones/" + vmInstance.Zone + "/instances/" + vmInstance.Name
@@ -418,7 +420,12 @@ func (p *Provider) GetVMSpecs(vms vm.List) ([]map[string]interface{}, error) {
 		if err := runJSONCommand(args, &vmSpec); err != nil {
 			return nil, errors.Wrapf(err, "error describing instance %s in zone %s", vmInstance.Name, vmInstance.Zone)
 		}
-		vmSpecs = append(vmSpecs, vmSpec)
+		name, ok := vmSpec["name"].(string)
+		if !ok {
+			l.Errorf("failed to create spec files for VM\n%v", vmSpec)
+			continue
+		}
+		vmSpecs[name] = vmSpec
 	}
 	return vmSpecs, nil
 }

pkg/roachprod/vm/local/local.go

@@ -141,7 +141,9 @@ func (p *Provider) GetHostErrorVMs(
 	return nil, nil
 }
 
-func (p *Provider) GetVMSpecs(vms vm.List) ([]map[string]interface{}, error) {
+func (p *Provider) GetVMSpecs(
+	l *logger.Logger, vms vm.List,
+) (map[string]map[string]interface{}, error) {
 	return nil, nil
 }
 

pkg/roachprod/vm/vm.go

@@ -510,8 +510,8 @@ type Provider interface {
 	GetPreemptedSpotVMs(l *logger.Logger, vms List, since time.Time) ([]PreemptedVM, error)
 	// GetHostErrorVMs returns a list of VMs that had host error since the time specified.
 	GetHostErrorVMs(l *logger.Logger, vms List, since time.Time) ([]string, error)
-	// GetVMSpecs returns a json list of VM specs, according to a specific cloud provider.
-	GetVMSpecs(vms List) ([]map[string]interface{}, error)
+	// GetVMSpecs returns a map from VM.Name to a map of VM attributes, according to a specific cloud provider.
+	GetVMSpecs(l *logger.Logger, vms List) (map[string]map[string]interface{}, error)
 
 	// CreateLoadBalancer creates a load balancer, for a specific port, that
 	// delegates to the given cluster.