refactor: move container into pkg

pkg/container/filters.go

@@ -0,0 +1,65 @@
+package container
+
+import t "github.com/containrrr/watchtower/pkg/types"
+
+// WatchtowerContainersFilter filters only watchtower containers
+func WatchtowerContainersFilter(c t.FilterableContainer) bool { return c.IsWatchtower() }
+
+// Filter no containers and returns all
+func noFilter(t.FilterableContainer) bool { return true }
+
+// Filters containers which don't have a specified name
+func filterByNames(names []string, baseFilter t.Filter) t.Filter {
+	if len(names) == 0 {
+		return baseFilter
+	}
+
+	return func(c t.FilterableContainer) bool {
+		for _, name := range names {
+			if (name == c.Name()) || (name == c.Name()[1:]) {
+				return baseFilter(c)
+			}
+		}
+		return false
+	}
+}
+
+// Filters out containers that don't have the 'enableLabel'
+func filterByEnableLabel(baseFilter t.Filter) t.Filter {
+	return func(c t.FilterableContainer) bool {
+		// If label filtering is enabled, containers should only be considered
+		// if the label is specifically set.
+		_, ok := c.Enabled()
+		if !ok {
+			return false
+		}
+
+		return baseFilter(c)
+	}
+}
+
+// Filters out containers that have a 'enableLabel' and is set to disable.
+func filterByDisabledLabel(baseFilter t.Filter) t.Filter {
+	return func(c t.FilterableContainer) bool {
+		enabledLabel, ok := c.Enabled()
+		if ok && !enabledLabel {
+			// If the label has been set and it demands a disable
+			return false
+		}
+
+		return baseFilter(c)
+	}
+}
+
+// BuildFilter creates the needed filter of containers
+func BuildFilter(names []string, enableLabel bool) t.Filter {
+	filter := noFilter
+	filter = filterByNames(names, filter)
+	if enableLabel {
+		// If label filtering is enabled, containers should only be considered
+		// if the label is specifically set.
+		filter = filterByEnableLabel(filter)
+	}
+	filter = filterByDisabledLabel(filter)
+	return filter
+}