feat(compute): improve error message when instance not found in zone (#805)

# Description
When `exo compute instance <action>` commands fail because the instance
does not exist in the default zone, the error message previously
surfaced a raw SDK message with no context:

```
"foo" not found in ListInstancesResponse: Not Found
```

This PR introduces a `findInstance` helper in
`cmd/compute/instance/instance.go` that wraps
`FindListInstancesResponseInstances` and enriches the not-found error
with the zone that was searched and a hint to use `-z`:

```
instance "foo" not found in zone ch-gva-2
Hint: use -z <zone> to specify a different zone, or run 'exo compute instance list' to see instances across all zones
```

Changes:

* Added `findInstance` helper in `cmd/compute/instance/instance.go`,
wrapping `FindListInstancesResponseInstances` with zone-aware error
enrichment.
* Migrated all 24 call sites across the instance subcommands (`show`,
`reboot`, `start`, `stop`, `scale`, `update`, `reset`, `reset-password`,
`reveal-password`, `resize-disk`, `scp`, `ssh`, `snapshot create`,
`snapshot revert`, `security-group add/remove`, `private-network
attach/detach/update-ip`, `elastic-ip attach/detach`, `enable-tpm`,
`console-url`, `delete`) to use the new helper.
* Added
`tests/e2e/scenarios/with-api/compute/instance_not_found_error.txtar`,
an API-driven e2e scenario verifying the enriched error message on
`show`, `reboot` and `stop`. Uses the testscript runner from #804.
* Redirected `go test` stderr to stdout in `.github/workflows/e2e.yml`
to suppress a spurious "Error" banner in the GitHub Actions UI that
appeared when the test runner wrote to stderr, even though the job
itself succeeded.

## Checklist
(For exoscale contributors)

* [x] Changelog updated (under *Unreleased* block, and add the Pull
Request #number for each bit you add to the `CHANGELOG.md`)
* [x] Testing

## Testing

Covered by the e2e scenario above (requires API credentials, runs under
`-tags=api`).

Author: natalie-o-perret

.github/workflows/e2e.yml

@@ -44,4 +44,4 @@ jobs:
           EXOSCALE_ZONE: ch-gva-2
         run: |
           cd tests/e2e
-          go test -v -tags=api -timeout 30m -run TestScriptsAPI
+          go test -v -tags=api -timeout 30m -run TestScriptsAPI 2>&1

CHANGELOG.md

@@ -7,6 +7,10 @@
 - dbaas: add missing PostgreSQL configuration options (`shared-buffers-percentage`, `synchronous-replication`, `timescaledb-settings`, `variant`, `work-mem`) #808
 - `exo compute eip list` now shows the description & the management type of the EIP #803
 - sks: add `rotate-karpenter-credentials` command #797
+
+### Improvements
+
+- compute instance: enrich "not found" error with the zone searched and a hint to use -z #805
 - sks: add `active-nodepool-templates` command #797
 - new command `exo ai deployment instance-type` that allows showing what GPU is usable in which zone #809
 

cmd/compute/instance/instance.go

@@ -1,7 +1,11 @@
 package instance
 
 import (
+	"errors"
+	"fmt"
+
 	"github.com/exoscale/cli/cmd/compute"
+	v3 "github.com/exoscale/egoscale/v3"
 	"github.com/spf13/cobra"
 )
 
@@ -36,3 +40,21 @@ var instanceCmd = &cobra.Command{
 func init() {
 	compute.ComputeCmd.AddCommand(instanceCmd)
 }
+
+// findInstance looks up an instance by name or ID from a ListInstancesResponse
+// and enriches the "not found" error with the zone that was searched,
+// reminding the user to use -z to target a different zone.
+func findInstance(resp *v3.ListInstancesResponse, nameOrID, zone string) (v3.ListInstancesResponseInstances, error) {
+	instance, err := resp.FindListInstancesResponseInstances(nameOrID)
+	if err != nil {
+		if errors.Is(err, v3.ErrNotFound) {
+			return v3.ListInstancesResponseInstances{}, fmt.Errorf(
+				"instance %q not found in zone %s\nHint: use -z <zone> to specify a different zone, or run 'exo compute instance list' to see instances across all zones",
+				nameOrID,
+				zone,
+			)
+		}
+		return v3.ListInstancesResponseInstances{}, err
+	}
+	return instance, nil
+}

cmd/compute/instance/instance_console_url.go

@@ -60,7 +60,7 @@ func (c *instanceConsoleURLCmd) CmdRun(cmd *cobra.Command, _ []string) error {
 		return err
 	}
 
-	foundInstance, err := resp.FindListInstancesResponseInstances(c.Instance)
+	foundInstance, err := findInstance(resp, c.Instance, string(c.Zone))
 	if err != nil {
 		return err
 	}

cmd/compute/instance/instance_delete.go

@@ -54,7 +54,7 @@ func (c *instanceDeleteCmd) CmdRun(_ *cobra.Command, _ []string) error {
 
 	instanceToDelete := []v3.UUID{}
 	for _, i := range c.Instances {
-		instance, err := instances.FindListInstancesResponseInstances(i)
+		instance, err := findInstance(instances, i, c.Zone)
 		if err != nil {
 			if !c.Force {
 				return err

cmd/compute/instance/instance_elastic_ip_attach.go

@@ -54,9 +54,9 @@ func (c *instanceEIPAttachCmd) CmdRun(_ *cobra.Command, _ []string) error {
 	if err != nil {
 		return err
 	}
-	instance, err := instancesList.FindListInstancesResponseInstances(c.Instance)
+	instance, err := findInstance(instancesList, c.Instance, c.Zone)
 	if err != nil {
-		return fmt.Errorf("error retrieving Instance: %w", err)
+		return err
 	}
 
 	elasticIPs, err := client.ListElasticIPS(ctx)

cmd/compute/instance/instance_elastic_ip_detach.go

@@ -54,7 +54,7 @@ func (c *instanceEIPDetachCmd) CmdRun(_ *cobra.Command, _ []string) error {
 	if err != nil {
 		return err
 	}
-	instance, err := instancesList.FindListInstancesResponseInstances(c.Instance)
+	instance, err := findInstance(instancesList, c.Instance, c.Zone)
 	if err != nil {
 		return fmt.Errorf("error retrieving Instance: %w", err)
 	}

cmd/compute/instance/instance_enable_tpm.go

@@ -45,7 +45,7 @@ func (c *instanceEnableTPMCmd) CmdRun(_ *cobra.Command, _ []string) error {
 		return err
 	}
 
-	instance, err := resp.FindListInstancesResponseInstances(c.Instance)
+	instance, err := findInstance(resp, c.Instance, string(c.Zone))
 	if err != nil {
 		return err
 	}

cmd/compute/instance/instance_private_network_attach.go

@@ -56,7 +56,7 @@ func (c *instancePrivnetAttachCmd) CmdRun(_ *cobra.Command, _ []string) error {
 	if err != nil {
 		return err
 	}
-	instance, err := instances.FindListInstancesResponseInstances(c.Instance)
+	instance, err := findInstance(instances, c.Instance, c.Zone)
 	if err != nil {
 		return err
 	}

cmd/compute/instance/instance_private_network_detach.go

@@ -54,7 +54,7 @@ func (c *instancePrivnetDetachCmd) CmdRun(_ *cobra.Command, _ []string) error {
 	if err != nil {
 		return err
 	}
-	instance, err := instances.FindListInstancesResponseInstances(c.Instance)
+	instance, err := findInstance(instances, c.Instance, c.Zone)
 	if err != nil {
 		return err
 	}