Implement readiness probes

Signed-off-by: Jan Dubois <[email protected]>

Author: jandubois

pkg/hostagent/requirements.go

@@ -2,6 +2,7 @@ package hostagent
 
 import (
 	"context"
+	"github.com/AkihiroSuda/lima/pkg/limayaml"
 	"time"
 
 	"github.com/AkihiroSuda/sshocker/pkg/ssh"
@@ -120,5 +121,14 @@ Also see "/var/log/cloud-init-output.log" in the guest.
 `,
 		})
 	}
+	for _, probe := range a.y.Probes {
+		if probe.Mode == limayaml.ProbeModeReadiness {
+			req = append(req, requirement{
+				description: probe.Description,
+				script:      probe.Script,
+				debugHint:   probe.Hint,
+			})
+		}
+	}
 	return req
 }

pkg/limayaml/default.TEMPLATE.yaml

@@ -85,3 +85,17 @@ containerd:
 #       set number
 #       EOF
 
+# probes:
+#  # Only `readiness` probes are supported right now.
+#  - mode: readiness
+#    description: vim to be installed
+#    script: |
+#       #!/bin/bash
+#       set -eux -o pipefail
+#       if ! timeout 30s bash -c "until command -v vim; do sleep 3; done"; then
+#         echo >&2 "vim is not installed yet"
+#         exit 1
+#       fi
+#    hint: |
+#      vim was not installed in the guest. Make sure the package system is working correctly.
+#      Also see "/var/log/cloud-init-output.log" in the guest.

pkg/limayaml/defaults.go

@@ -1,6 +1,9 @@
 package limayaml
 
-import "runtime"
+import (
+	"fmt"
+	"runtime"
+)
 
 func FillDefault(y *LimaYAML) {
 	y.Arch = resolveArch(y.Arch)
@@ -34,6 +37,15 @@ func FillDefault(y *LimaYAML) {
 	if y.Containerd.User == nil {
 		y.Containerd.User = &[]bool{true}[0]
 	}
+	for i := range y.Probes {
+		probe := &y.Probes[i]
+		if probe.Mode == "" {
+			probe.Mode = ProbeModeReadiness
+		}
+		if probe.Description == "" {
+			probe.Description = fmt.Sprintf("user probe %d/%d", i+1, len(y.Probes))
+		}
+	}
 }
 
 func resolveArch(s string) Arch {

pkg/limayaml/limayaml.go

@@ -12,6 +12,7 @@ type LimaYAML struct {
 	Video      Video       `yaml:"video,omitempty"`
 	Provision  []Provision `yaml:"provision,omitempty"`
 	Containerd Containerd  `yaml:"containerd,omitempty"`
+	Probes     []Probe     `yaml:"probes,omitempty"`
 }
 
 type Arch = string
@@ -62,3 +63,16 @@ type Containerd struct {
 	System *bool `yaml:"system,omitempty"`
 	User   *bool `yaml:"user,omitempty"`
 }
+
+type ProbeMode = string
+
+const (
+	ProbeModeReadiness ProbeMode = "readiness"
+)
+
+type Probe struct {
+	Mode        ProbeMode // default: "readiness"
+	Description string
+	Script      string
+	Hint        string
+}

pkg/limayaml/validate.go

@@ -111,6 +111,13 @@ func ValidateRaw(y LimaYAML) error {
 					i, ProvisionModeSystem, ProvisionModeUser)
 		}
 	}
-
+	for i, p := range y.Probes {
+		switch p.Mode {
+		case ProbeModeReadiness:
+		default:
+			return errors.Errorf("field `probe[%d].mode` can only be %q",
+				i, ProbeModeReadiness)
+		}
+	}
 	return nil
 }