Add config loading and dry-run validation

internal/config/validate.go

@@ -0,0 +1,153 @@
+package config
+
+import (
+	"fmt"
+	"regexp"
+	"strings"
+)
+
+var idPattern = regexp.MustCompile(`^[a-zA-Z0-9][a-zA-Z0-9._-]*$`)
+
+type ValidationErrors []string
+
+func (e ValidationErrors) Error() string {
+	if len(e) == 1 {
+		return e[0]
+	}
+	return strings.Join(e, "; ")
+}
+
+func Validate(cfg Config) error {
+	var errs ValidationErrors
+
+	if len(cfg.Pipelines) == 0 {
+		errs = append(errs, "pipelines is required")
+	}
+
+	pipelineIDs := make(map[string]struct{}, len(cfg.Pipelines))
+	for pipelineIndex, pipeline := range cfg.Pipelines {
+		pipelineContext := fmt.Sprintf("pipelines[%d]", pipelineIndex)
+		if pipeline.ID == "" {
+			errs = append(errs, pipelineContext+".id is required")
+		} else if !idPattern.MatchString(pipeline.ID) {
+			errs = append(errs, pipelineContext+".id must be a slug-like identifier")
+		} else if _, exists := pipelineIDs[pipeline.ID]; exists {
+			errs = append(errs, "pipeline id "+pipeline.ID+" is duplicated")
+		} else {
+			pipelineIDs[pipeline.ID] = struct{}{}
+		}
+
+		errs = validateBackend(errs, pipelineContext+".source", pipeline.Source.Backend, pipeline.Source.Path, pipeline.Source.URI, pipeline.Source.Endpoint, pipeline.Source.Bucket)
+		errs = validateValidationPolicy(errs, pipelineContext+".validation", pipeline.Validation)
+		if len(pipeline.Destinations) == 0 {
+			errs = append(errs, pipelineContext+".destinations is required")
+		}
+
+		destinationIDs := make(map[string]struct{}, len(pipeline.Destinations))
+		for destinationIndex, destination := range pipeline.Destinations {
+			destinationContext := fmt.Sprintf("%s.destinations[%d]", pipelineContext, destinationIndex)
+			if destination.ID == "" {
+				errs = append(errs, destinationContext+".id is required")
+			} else if !idPattern.MatchString(destination.ID) {
+				errs = append(errs, destinationContext+".id must be a slug-like identifier")
+			} else if _, exists := destinationIDs[destination.ID]; exists {
+				errs = append(errs, "destination id "+destination.ID+" is duplicated in pipeline "+pipeline.ID)
+			} else {
+				destinationIDs[destination.ID] = struct{}{}
+			}
+
+			errs = validateBackend(errs, destinationContext, destination.Backend, destination.Path, destination.URI, destination.Endpoint, destination.Bucket)
+			errs = validatePublishPolicy(errs, destinationContext+".publish", destination.Publish)
+			errs = validateTransform(errs, destinationContext+".transform", destination.Publish, destination.Transform)
+			errs = validateTransferPolicy(errs, destinationContext+".transfer", destination.Transfer)
+		}
+	}
+
+	if len(errs) > 0 {
+		return errs
+	}
+	return nil
+}
+
+func validateBackend(errs ValidationErrors, context, backend, path, uri, endpoint, bucket string) ValidationErrors {
+	switch backend {
+	case "":
+		errs = append(errs, context+".backend is required")
+	case BackendLocal:
+		if path == "" {
+			errs = append(errs, context+".path is required for local backend")
+		}
+	case BackendSSH:
+		if uri == "" {
+			errs = append(errs, context+".uri is required for ssh backend")
+		}
+		if path == "" {
+			errs = append(errs, context+".path is required for ssh backend")
+		}
+	case BackendS3:
+		if endpoint == "" {
+			errs = append(errs, context+".endpoint is required for s3 backend")
+		}
+		if bucket == "" {
+			errs = append(errs, context+".bucket is required for s3 backend")
+		}
+	default:
+		errs = append(errs, context+".backend "+backend+" is unsupported")
+	}
+	return errs
+}
+
+func validateValidationPolicy(errs ValidationErrors, context string, policy ValidationPolicy) ValidationErrors {
+	if policy.OnDigestMismatch != ValidationActionFail {
+		errs = append(errs, context+".on_digest_mismatch must be "+ValidationActionFail)
+	}
+	return errs
+}
+
+func validatePublishPolicy(errs ValidationErrors, context string, policy *PublishPolicy) ValidationErrors {
+	if policy == nil {
+		errs = append(errs, context+" is required")
+		return errs
+	}
+	if !policy.Source && !policy.HTML {
+		errs = append(errs, context+" must enable source or html")
+	}
+	return errs
+}
+
+func validateTransform(errs ValidationErrors, context string, publish *PublishPolicy, transform Transform) ValidationErrors {
+	publishesHTML := publish != nil && publish.HTML
+	if transform.MarkdownToHTML == nil {
+		if publishesHTML {
+			errs = append(errs, context+".markdown_to_html is required when publish.html is true")
+		}
+		return errs
+	}
+
+	if publishesHTML && !transform.MarkdownToHTML.Enabled {
+		errs = append(errs, context+".markdown_to_html.enabled must be true when publish.html is true")
+	}
+	if transform.MarkdownToHTML.Enabled && transform.MarkdownToHTML.Mode != TransformModeSidecar {
+		errs = append(errs, context+".markdown_to_html.mode must be "+TransformModeSidecar)
+	}
+	if !transform.MarkdownToHTML.Enabled && transform.MarkdownToHTML.Mode != "" && transform.MarkdownToHTML.Mode != TransformModeSidecar {
+		errs = append(errs, context+".markdown_to_html.mode must be "+TransformModeSidecar)
+	}
+	return errs
+}
+
+func validateTransferPolicy(errs ValidationErrors, context string, policy TransferPolicy) ValidationErrors {
+	if policy.OnDestinationSame != TransferActionSkip && policy.OnDestinationSame != TransferActionFail {
+		errs = append(errs, context+".on_destination_same must be skip or fail")
+	}
+	if policy.OnDestinationOlder != TransferActionReplace && policy.OnDestinationOlder != TransferActionFail {
+		errs = append(errs, context+".on_destination_older must be replace or fail")
+	}
+	if policy.OnDestinationNewer != TransferActionSkip && policy.OnDestinationNewer != TransferActionFail {
+		errs = append(errs, context+".on_destination_newer must be skip or fail")
+	}
+	if policy.OnConflict != TransferActionFail {
+		errs = append(errs, context+".on_conflict must be fail")
+	}
+	return errs
+}