feat: migrate builds plugin to go and track per-build records

Adds typed JSON build records under data/builds/<app>/<build-id>.{json,log} keyed on a stable base36 ULID-style DOKKU_BUILD_ID generated for every deploy. The new commands surface that history (builds:list, builds:info, builds:prune) and an operator-configurable retention via builds:set retention. The existing builds:cancel and builds:output now key on the build-id (with safe handling for already-finalized and abandoned records), and the per-build log file replaces journalctl as the durable source of truth for builds:output.

plugins/builds/report.go

@@ -0,0 +1,130 @@
+package builds
+
+import (
+	"strconv"
+	"time"
+
+	"github.com/dokku/dokku/plugins/common"
+)
+
+// ReportSingleApp emits the report for one app (or --global).
+func ReportSingleApp(appName, format, infoFlag string) error {
+	if appName != "--global" {
+		if err := common.VerifyAppName(appName); err != nil {
+			return err
+		}
+	}
+
+	var flags map[string]common.ReportFunc
+	if appName == "--global" {
+		flags = map[string]common.ReportFunc{
+			"--builds-global-retention": reportGlobalRetention,
+		}
+	} else {
+		flags = map[string]common.ReportFunc{
+			"--build-id":                  reportBuildID,
+			"--build-kind":                reportBuildKind,
+			"--build-status":              reportBuildStatus,
+			"--build-pid":                 reportBuildPID,
+			"--build-source":              reportBuildSource,
+			"--build-started-at":          reportBuildStartedAt,
+			"--build-finished-at":         reportBuildFinishedAt,
+			"--build-exit-code":           reportBuildExitCode,
+			"--builds-retention":          reportRetention,
+			"--builds-global-retention":   reportGlobalRetention,
+			"--builds-computed-retention": reportComputedRetention,
+		}
+	}
+
+	flagKeys := make([]string, 0, len(flags))
+	for k := range flags {
+		flagKeys = append(flagKeys, k)
+	}
+
+	infoFlags := common.CollectReport(appName, infoFlag, flags)
+	return common.ReportSingleApp("builds", appName, infoFlag, infoFlags, flagKeys, format, false, true)
+}
+
+func mostRecentBuild(appName string) (Build, bool) {
+	builds, err := FetchBuilds(appName)
+	if err != nil || len(builds) == 0 {
+		return Build{}, false
+	}
+	return builds[0], true
+}
+
+func reportBuildID(appName string) string {
+	b, ok := mostRecentBuild(appName)
+	if !ok {
+		return ""
+	}
+	return b.ID
+}
+
+func reportBuildKind(appName string) string {
+	b, ok := mostRecentBuild(appName)
+	if !ok {
+		return ""
+	}
+	return string(b.Kind)
+}
+
+func reportBuildStatus(appName string) string {
+	b, ok := mostRecentBuild(appName)
+	if !ok {
+		return ""
+	}
+	return string(b.DisplayStatus())
+}
+
+func reportBuildPID(appName string) string {
+	b, ok := mostRecentBuild(appName)
+	if !ok {
+		return ""
+	}
+	return strconv.Itoa(b.PID)
+}
+
+func reportBuildSource(appName string) string {
+	b, ok := mostRecentBuild(appName)
+	if !ok {
+		return ""
+	}
+	return string(b.Source)
+}
+
+func reportBuildStartedAt(appName string) string {
+	b, ok := mostRecentBuild(appName)
+	if !ok {
+		return ""
+	}
+	return b.StartedAt.Format(time.RFC3339)
+}
+
+func reportBuildFinishedAt(appName string) string {
+	b, ok := mostRecentBuild(appName)
+	if !ok || b.FinishedAt == nil {
+		return ""
+	}
+	return b.FinishedAt.Format(time.RFC3339)
+}
+
+func reportBuildExitCode(appName string) string {
+	b, ok := mostRecentBuild(appName)
+	if !ok || b.ExitCode == nil {
+		return ""
+	}
+	return strconv.Itoa(*b.ExitCode)
+}
+
+func reportRetention(appName string) string {
+	return common.PropertyGet("builds", appName, "retention")
+}
+
+func reportGlobalRetention(_ string) string {
+	return common.PropertyGet("builds", "--global", "retention")
+}
+
+func reportComputedRetention(appName string) string {
+	return strconv.Itoa(ResolveRetention(appName))
+}