feat(discovery): orchestrate match, opt-in filter, dedup, path-check

internal/discovery/discovery.go

@@ -0,0 +1,89 @@
+package discovery
+
+import (
+	"context"
+	"fmt"
+	"sort"
+	"strings"
+
+	"github.com/docker/docker/api/types/container"
+)
+
+// Job describes a single (project, service, config_files) update to execute.
+type Job struct {
+	Project    string
+	Service    string
+	WorkingDir string
+	ConfigFiles []string
+	// Refused is true when the WorkingDir falls outside STACKS_ROOT.
+	// The job is returned so the caller can surface a per-job "refused"
+	// result, but it MUST NOT be executed.
+	Refused       bool
+	RefusedReason string
+}
+
+// Discovery orchestrates "given an image, what jobs should we enqueue?".
+type Discovery struct {
+	cli        DockerClient
+	stacksRoot string
+	optInLabel string
+}
+
+// New returns a Discovery bound to the given Docker client and config.
+func New(cli DockerClient, stacksRoot, optInLabel string) *Discovery {
+	return &Discovery{cli: cli, stacksRoot: stacksRoot, optInLabel: optInLabel}
+}
+
+// FindJobs lists running containers, filters by image match + opt-in label,
+// extracts Compose info, applies the path safety check, and deduplicates.
+func (d *Discovery) FindJobs(ctx context.Context, image string) ([]Job, error) {
+	all, err := d.cli.ContainerList(ctx, container.ListOptions{All: true})
+	if err != nil {
+		return nil, fmt.Errorf("docker container list: %w", err)
+	}
+
+	seen := make(map[string]struct{})
+	var jobs []Job
+
+	for _, c := range all {
+		if !ImagesMatch(image, c.Image) {
+			continue
+		}
+		if !HasOptIn(c.Labels, d.optInLabel) {
+			continue
+		}
+		cl, err := ParseComposeLabels(c.Labels)
+		if err != nil {
+			continue
+		}
+
+		refused := !IsInsideRoot(d.stacksRoot, cl.WorkingDir)
+		reason := ""
+		if refused {
+			reason = fmt.Sprintf("working_dir %q outside STACKS_ROOT %q", cl.WorkingDir, d.stacksRoot)
+		}
+
+		key := dedupKey(cl)
+		if _, dup := seen[key]; dup {
+			continue
+		}
+		seen[key] = struct{}{}
+
+		jobs = append(jobs, Job{
+			Project:       cl.Project,
+			Service:       cl.Service,
+			WorkingDir:    cl.WorkingDir,
+			ConfigFiles:   cl.ConfigFiles,
+			Refused:       refused,
+			RefusedReason: reason,
+		})
+	}
+
+	return jobs, nil
+}
+
+func dedupKey(cl ComposeLabels) string {
+	files := append([]string(nil), cl.ConfigFiles...)
+	sort.Strings(files)
+	return cl.Project + "|" + cl.Service + "|" + strings.Join(files, ",")
+}