move implementation to internal/ directory (#828)

internal/zfs/mapping.go

@@ -0,0 +1,107 @@
+package zfs
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/zrepl/zrepl/internal/zfs/zfscmd"
+)
+
+type DatasetFilter interface {
+	Filter(p *DatasetPath) (pass bool, err error)
+	// The caller owns the returned set.
+	// Implementations should return a copy.
+	UserSpecifiedDatasets() UserSpecifiedDatasetsSet
+}
+
+// A set of dataset names that the user specified in the configuration file.
+type UserSpecifiedDatasetsSet map[string]bool
+
+// Returns a DatasetFilter that does not filter (passes all paths)
+func NoFilter() DatasetFilter {
+	return noFilter{}
+}
+
+type noFilter struct{}
+
+var _ DatasetFilter = noFilter{}
+
+func (noFilter) Filter(p *DatasetPath) (pass bool, err error)    { return true, nil }
+func (noFilter) UserSpecifiedDatasets() UserSpecifiedDatasetsSet { return nil }
+
+func ZFSListMapping(ctx context.Context, filter DatasetFilter) (datasets []*DatasetPath, err error) {
+	res, err := ZFSListMappingProperties(ctx, filter, nil)
+	if err != nil {
+		return nil, err
+	}
+	datasets = make([]*DatasetPath, len(res))
+	for i, r := range res {
+		datasets[i] = r.Path
+	}
+	return datasets, nil
+}
+
+type ZFSListMappingPropertiesResult struct {
+	Path *DatasetPath
+	// Guaranteed to have the same length as properties in the originating call
+	Fields []string
+}
+
+// properties must not contain 'name'
+func ZFSListMappingProperties(ctx context.Context, filter DatasetFilter, properties []string) (datasets []ZFSListMappingPropertiesResult, err error) {
+
+	if filter == nil {
+		panic("filter must not be nil")
+	}
+
+	for _, p := range properties {
+		if p == "name" {
+			panic("properties must not contain 'name'")
+		}
+	}
+	newProps := make([]string, len(properties)+1)
+	newProps[0] = "name"
+	copy(newProps[1:], properties)
+	properties = newProps
+
+	ctx, cancel := context.WithCancel(ctx)
+	defer cancel()
+	rchan := make(chan ZFSListResult)
+
+	go ZFSListChan(ctx, rchan, properties, nil, "-r", "-t", "filesystem,volume")
+
+	unmatchedUserSpecifiedDatasets := filter.UserSpecifiedDatasets()
+	datasets = make([]ZFSListMappingPropertiesResult, 0)
+	for r := range rchan {
+
+		if r.Err != nil {
+			err = r.Err
+			return
+		}
+
+		var path *DatasetPath
+		if path, err = NewDatasetPath(r.Fields[0]); err != nil {
+			return
+		}
+
+		delete(unmatchedUserSpecifiedDatasets, path.ToString())
+
+		pass, filterErr := filter.Filter(path)
+		if filterErr != nil {
+			return nil, fmt.Errorf("error calling filter: %s", filterErr)
+		}
+		if pass {
+			datasets = append(datasets, ZFSListMappingPropertiesResult{
+				Path:   path,
+				Fields: r.Fields[1:],
+			})
+		}
+
+	}
+
+	jobid := zfscmd.GetJobIDOrDefault(ctx, "__nojobid")
+	metric := prom.ZFSListUnmatchedUserSpecifiedDatasetCount.WithLabelValues(jobid)
+	metric.Add(float64(len(unmatchedUserSpecifiedDatasets)))
+
+	return
+}