Add remote session loading

internal/app/config_loader.go

@@ -0,0 +1,133 @@
+package app
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"gitea.maximumdirect.net/eric/narratio/internal/adapters/storage"
+	"gitea.maximumdirect.net/eric/narratio/internal/artifacts"
+	"gitea.maximumdirect.net/eric/narratio/internal/config"
+)
+
+func loadCommandConfig(ctx context.Context, pipelineFlag, campaignFlag, sessionFlag string, sessionOpts config.SessionLoadOptions) (*config.Config, error) {
+	resolvedPipelinePath, err := resolvePipelineConfigPath(pipelineFlag)
+	if err != nil {
+		return nil, err
+	}
+	resolvedCampaignPath, err := resolveCampaignConfigPath(campaignFlag)
+	if err != nil {
+		return nil, err
+	}
+
+	if explicitSession := strings.TrimSpace(sessionFlag); explicitSession != "" {
+		return config.LoadWithSessionOptions(resolvedPipelinePath, resolvedCampaignPath, explicitSession, sessionOpts)
+	}
+
+	discoveredSession, err := discoverSessionConfigPathWithCandidates(config.DefaultSessionConfigSearchPaths)
+	if err != nil {
+		return nil, err
+	}
+	if discoveredSession.Path != "" {
+		return config.LoadWithSessionOptions(resolvedPipelinePath, resolvedCampaignPath, discoveredSession.Path, sessionOpts)
+	}
+
+	pipelineCfg, err := config.LoadPipeline(resolvedPipelinePath)
+	if err != nil {
+		return nil, err
+	}
+	campaignCfg, err := config.LoadCampaign(resolvedCampaignPath)
+	if err != nil {
+		return nil, err
+	}
+
+	sessionID := strings.TrimSpace(sessionOpts.SessionID)
+	if sessionID == "" {
+		return nil, missingSessionConfigError(discoveredSession.Searched, "remote session loading requires --session-id")
+	}
+
+	sessionPrefix := artifacts.S3SessionPrefix(pipelineCfg.Storage.S3.RootPrefix, campaignCfg.Campaign, sessionID)
+	remoteKey := artifacts.S3SessionConfigKey(sessionPrefix)
+	partialCfg := &config.Config{
+		Pipeline:     pipelineCfg,
+		Campaign:     campaignCfg,
+		PipelinePath: resolvedPipelinePath,
+		CampaignPath: resolvedCampaignPath,
+	}
+	store, err := newObjectStoreFromConfigFn(ctx, partialCfg)
+	if err != nil {
+		return nil, missingSessionConfigError(discoveredSession.Searched, fmt.Sprintf("remote session %q unavailable: %v", remoteKey, err))
+	}
+
+	sessionInfo, err := findRemoteSessionConfig(ctx, store, sessionPrefix, remoteKey)
+	if err != nil {
+		return nil, missingSessionConfigError(discoveredSession.Searched, err.Error())
+	}
+	sessionTempPath, err := downloadRemoteSessionConfig(ctx, store, remoteKey)
+	if err != nil {
+		return nil, missingSessionConfigError(discoveredSession.Searched, fmt.Sprintf("remote session %q download failed: %v", remoteKey, err))
+	}
+	sessionBytes, err := os.ReadFile(sessionTempPath)
+	if err != nil {
+		return nil, fmt.Errorf("read downloaded remote session %q: %w", sessionTempPath, err)
+	}
+	sessionCfg, err := config.LoadSessionBytesWithOptions("s3://"+s3BucketName(pipelineCfg)+"/"+remoteKey, sessionBytes, sessionOpts)
+	if err != nil {
+		return nil, err
+	}
+
+	return config.Resolve(
+		resolvedPipelinePath,
+		pipelineCfg,
+		resolvedCampaignPath,
+		campaignCfg,
+		sessionTempPath,
+		sessionCfg,
+		config.SessionSource{
+			Source:    "session_config.s3",
+			LocalPath: sessionTempPath,
+			S3Bucket:  s3BucketName(pipelineCfg),
+			S3Key:     remoteKey,
+			S3Size:    sessionInfo.Size,
+			S3ETag:    sessionInfo.ETag,
+			SpoolPath: sessionTempPath,
+		},
+	)
+}
+
+func findRemoteSessionConfig(ctx context.Context, store storage.ObjectStore, sessionPrefix, remoteKey string) (storage.ObjectInfo, error) {
+	objects, err := store.List(ctx, sessionPrefix)
+	if err != nil {
+		return storage.ObjectInfo{}, fmt.Errorf("remote session %q list failed: %w", remoteKey, err)
+	}
+	for _, obj := range objects {
+		if obj.Key == remoteKey {
+			return obj, nil
+		}
+	}
+	return storage.ObjectInfo{}, fmt.Errorf("remote session %q not found", remoteKey)
+}
+
+func downloadRemoteSessionConfig(ctx context.Context, store storage.ObjectStore, remoteKey string) (string, error) {
+	f, err := os.CreateTemp("", "narratio-session-*.yml")
+	if err != nil {
+		return "", fmt.Errorf("create temp file: %w", err)
+	}
+	path := f.Name()
+	if err := f.Close(); err != nil {
+		return "", fmt.Errorf("close temp file %q: %w", path, err)
+	}
+	if err := store.Download(ctx, remoteKey, path); err != nil {
+		return "", err
+	}
+	return filepath.Clean(path), nil
+}
+
+func s3BucketName(cfg *config.PipelineConfig) string {
+	if cfg == nil || cfg.Storage.S3 == nil {
+		return ""
+	}
+	return strings.TrimSpace(cfg.Storage.S3.Bucket)
+}