feat: master/agent phase 4 — registry polling and version history (#9) (#23)

internal/master/model/job.go

@@ -15,8 +15,20 @@ var (
 	// ErrAgentTooOld means the only agent that could run the job speaks a
 	// protocol version without jobs.
 	ErrAgentTooOld = errors.New("agent too old for updates")
+	// ErrAgentTooOldForPinned means the only agent that could run the job
+	// speaks protocol version 2, which cannot deploy a digest-pinned or
+	// tagless ref. errors.Is(err, ErrAgentTooOld) is true for it as well.
+	ErrAgentTooOldForPinned error = agentTooOldForPinned{}
 )
 
+type agentTooOldForPinned struct{}
+
+func (agentTooOldForPinned) Error() string {
+	return "agent too old to deploy a pinned version (needs protocol 3)"
+}
+
+func (agentTooOldForPinned) Is(target error) bool { return target == ErrAgentTooOld }
+
 // NotUpdatableError says why a service cannot be updated. Reason is shown
 // in the UI as is.
 type NotUpdatableError struct {

internal/master/model/model.go

@@ -8,6 +8,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/shcizo/package-updater/internal/imageref"
 	"github.com/shcizo/package-updater/internal/protocol"
 )
 
@@ -56,11 +57,20 @@ type Service struct {
 	// AvailableRef is the newest ref a webhook or poll reported for this
 	// service; "" if none, or if a later job already deployed it.
 	AvailableRef    string
-	AvailableSource string // SourceWebhook; "" when AvailableRef is empty
+	AvailableDigest string // digest of AvailableRef when known (poll); "" from the webhook
+	AvailableSource string // SourceWebhook or SourcePoll; "" when AvailableRef is empty
 	AvailableAt     *time.Time
-	FirstSeenAt     time.Time
-	UpdatedAt       time.Time
-	RemovedAt       *time.Time
+	LastPollError   string // last registry error for the followed ref; "" when fine
+	// LastTagDigest is the newest digest of the followed tag that was deployed
+	// or started: set when the poller starts an auto job, when it sees the service
+	// already running that digest, and when any plain tag job succeeds (the
+	// digest the agent pinned); "" if never. The poller does
+	// not start another job for the same digest, so a rollback sticks until the
+	// registry shows a different one.
+	LastTagDigest string
+	FirstSeenAt   time.Time
+	UpdatedAt     time.Time
+	RemovedAt     *time.Time
 }
 
 // Update modes of a service.
@@ -69,18 +79,40 @@ const (
 	ModeAuto   = "auto"
 )
 
-// Sources of an available ref.
+// Sources of an available ref and of an ImageVersion.
 const (
 	SourceWebhook = "webhook"
+	SourcePoll    = "poll"
+	// SourceRunning is used by image_versions only: an agent reported the
+	// version as running.
+	SourceRunning = "running"
 )
 
 // Available is a newer ref reported for a service.
 type Available struct {
 	Ref    string
-	Source string // SourceWebhook
+	Digest string // "" when unknown (webhook)
+	Source string // SourceWebhook or SourcePoll
 	At     time.Time
 }
 
+// ImageVersion is one version of an image repo the master has seen. Tag and
+// Digest are "" when the version has no tag or its digest is unknown; they
+// are never both empty.
+type ImageVersion struct {
+	ID          int64
+	Repo        string
+	Tag         string
+	Digest      string
+	Source      string // SourceWebhook, SourcePoll or SourceRunning: the first source that saw it
+	FirstSeenAt time.Time
+}
+
+// Ref returns "repo:tag@digest", "repo:tag" or "repo@digest".
+func (v ImageVersion) Ref() string {
+	return imageref.Ref{Repo: v.Repo, Tag: v.Tag, Digest: v.Digest}.String()
+}
+
 // DisplayName is the human-facing name of the service.
 func (s Service) DisplayName() string {
 	switch s.Kind {

internal/master/model/model_test.go

@@ -40,6 +40,24 @@ func TestDisplayName(t *testing.T) {
 	}
 }
 
+func TestImageVersionRef(t *testing.T) {
+	cases := []struct {
+		name string
+		v    ImageVersion
+		want string
+	}{
+		{"tag and digest", ImageVersion{Repo: "r/x", Tag: "1", Digest: "sha256:a"}, "r/x:1@sha256:a"},
+		{"tag only", ImageVersion{Repo: "r/x", Tag: "1"}, "r/x:1"},
+		{"digest only", ImageVersion{Repo: "r/x", Digest: "sha256:a"}, "r/x@sha256:a"},
+		{"registry port", ImageVersion{Repo: "localhost:5000/x", Tag: "1"}, "localhost:5000/x:1"},
+	}
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			assert.Equal(t, c.want, c.v.Ref())
+		})
+	}
+}
+
 func TestJob_Active(t *testing.T) {
 	cases := []struct {
 		status JobStatus