aws: errors with context

When faced with errors from cloud providers (like "Throttling: Rate exceeded"), it's not always easy to find what operation caused the failure, and what action was aborted, if any,

Let's make it easier to identify an error source (and affected object when possible) by providing more context (and by using easy to find error messages).

CHANGELOG.md

@@ -1,5 +1,6 @@
 ## Unreleased
 
+- Improve errors context for AWS provider
 
 ## v0.7.3 - 2020-08-05
 

provider/aws/aws.go

@@ -30,6 +30,7 @@ import (
 	"github.com/aws/aws-sdk-go/aws/session"
 	"github.com/aws/aws-sdk-go/service/route53"
 	"github.com/linki/instrumented_http"
+	"github.com/pkg/errors"
 	log "github.com/sirupsen/logrus"
 
 	"sigs.k8s.io/external-dns/endpoint"
@@ -166,7 +167,7 @@ func NewAWSProvider(awsConfig AWSConfig) (*AWSProvider, error) {
 		SharedConfigState: session.SharedConfigEnable,
 	})
 	if err != nil {
-		return nil, err
+		return nil, errors.Wrap(err, "failed to instantiate AWS session")
 	}
 
 	if awsConfig.AssumeRole != "" {
@@ -229,10 +230,10 @@ func (p *AWSProvider) Zones(ctx context.Context) (map[string]*route53.HostedZone
 
 	err := p.client.ListHostedZonesPagesWithContext(ctx, &route53.ListHostedZonesInput{}, f)
 	if err != nil {
-		return nil, err
+		return nil, errors.Wrap(err, "failed to list hosted zones")
 	}
 	if tagErr != nil {
-		return nil, tagErr
+		return nil, errors.Wrap(tagErr, "failed to list zones tags")
 	}
 
 	for _, zone := range zones {
@@ -255,7 +256,7 @@ func wildcardUnescape(s string) string {
 func (p *AWSProvider) Records(ctx context.Context) (endpoints []*endpoint.Endpoint, _ error) {
 	zones, err := p.Zones(ctx)
 	if err != nil {
-		return nil, err
+		return nil, errors.Wrap(err, "records retrieval failed")
 	}
 
 	return p.records(ctx, zones)
@@ -339,7 +340,7 @@ func (p *AWSProvider) records(ctx context.Context, zones map[string]*route53.Hos
 		}
 
 		if err := p.client.ListResourceRecordSetsPagesWithContext(ctx, params, f); err != nil {
-			return nil, err
+			return nil, errors.Wrapf(err, "failed to list resource records sets for zone %s", *z.Id)
 		}
 	}
 
@@ -364,12 +365,12 @@ func (p *AWSProvider) DeleteRecords(ctx context.Context, endpoints []*endpoint.E
 func (p *AWSProvider) doRecords(ctx context.Context, action string, endpoints []*endpoint.Endpoint) error {
 	zones, err := p.Zones(ctx)
 	if err != nil {
-		return err
+		return errors.Wrapf(err, "failed to list zones, aborting %s doRecords action", action)
 	}
 
 	records, err := p.records(ctx, zones)
 	if err != nil {
-		log.Errorf("getting records failed: %v", err)
+		log.Errorf("failed to list records while preparing %s doRecords action: %s", action, err)
 	}
 	return p.submitChanges(ctx, p.newChanges(action, endpoints, records, zones), zones)
 }
@@ -378,15 +379,15 @@ func (p *AWSProvider) doRecords(ctx context.Context, action string, endpoints []
 func (p *AWSProvider) ApplyChanges(ctx context.Context, changes *plan.Changes) error {
 	zones, err := p.Zones(ctx)
 	if err != nil {
-		return err
+		return errors.Wrap(err, "failed to list zones, not applying changes")
 	}
 
 	records, ok := ctx.Value(provider.RecordsContextKey).([]*endpoint.Endpoint)
 	if !ok {
 		var err error
 		records, err = p.records(ctx, zones)
 		if err != nil {
-			log.Errorf("getting records failed: %v", err)
+			log.Errorf("failed to get records while preparing to applying changes: %s", err)
 		}
 	}
 
@@ -581,7 +582,7 @@ func (p *AWSProvider) tagsForZone(ctx context.Context, zoneID string) (map[strin
 		ResourceId:   aws.String(zoneID),
 	})
 	if err != nil {
-		return nil, err
+		return nil, errors.Wrapf(err, "failed to list tags for zone %s", zoneID)
 	}
 	tagMap := map[string]string{}
 	for _, tag := range response.ResourceTagSet.Tags {