refact: add servers.ListWorkers(...)

refactor servers.(repository).ListWorkers(...) into just
servers.ListWorkers(...) used independently of the repo.  The method
func is refactor to use the new bits as well.

internal/server/options.go

@@ -119,7 +119,15 @@ func WithUpdateTags(updateTags bool) Option {
 // WithWorkerTags provides worker tags.
 func WithWorkerTags(tags ...*Tag) Option {
 	return func(o *options) {
-		o.withWorkerTags = tags
+		newTags := []*Tag{}
+		for _, tag := range tags {
+			if tag != nil {
+				newTags = append(newTags, tag)
+			}
+		}
+		if len(newTags) > 0 {
+			o.withWorkerTags = tags
+		}
 	}
 }
 

internal/server/repository_worker.go

@@ -166,15 +166,53 @@ func lookupWorker(ctx context.Context, reader db.Reader, id string) (*Worker, er
 }
 
 // ListWorkers will return a listing of Workers and honor the WithLimit option.
+// Supported options: WithWorkerType, WithActiveWorkers, WithLiveness,
+// WithWorkerPool, WithLimit
+//
 // If WithLiveness is zero the default liveness value is used, if it is negative
 // then the last status update time is ignored.
 // If WithLimit < 0, then unlimited results are returned. If WithLimit == 0, then
 // default limits are used for results.  WithWorkerPool can be provided with a
 // non-zero length slice of worker ids to restrict the returned workers to only
 // ones with the ids provided.
-// Also supports: WithWorkerType, WithActiveWorkers
 func (r *Repository) ListWorkers(ctx context.Context, scopeIds []string, opt ...Option) ([]*Worker, error) {
 	const op = "server.(Repository).ListWorkers"
+
+	opts := GetOpts(opt...)
+	newOpts := []Option{}
+	// handle the WithLimit default for the repo
+	switch {
+	case opts.withLimit != 0:
+		newOpts = append(newOpts, WithLimit(opts.withLimit))
+	default:
+		newOpts = append(newOpts, WithLimit(r.defaultLimit))
+	}
+	// handle the WithLiveness default
+	switch {
+	case opts.withLiveness != 0:
+		newOpts = append(newOpts, WithLiveness(opts.withLiveness))
+	default:
+		newOpts = append(newOpts, WithLiveness(DefaultLiveness))
+
+	}
+	newOpts = append(newOpts, WithWorkerType(opts.withWorkerType))
+	newOpts = append(newOpts, WithActiveWorkers(opts.withActiveWorkers))
+	newOpts = append(newOpts, WithWorkerPool(opts.withWorkerPool))
+	return ListWorkers(ctx, r.reader, scopeIds, newOpts...)
+}
+
+// ListWorkers will return a listing of Workers and honor the WithLimit option.
+// Supported options: WithWorkerType, WithActiveWorkers, WithLiveness,
+// WithWorkerPool, WithLimit
+//
+// If WithLiveness is zero the default liveness value is used, if it is negative
+// then the last status update time is ignored.
+// If WithLimit < 0, then unlimited results are returned. If WithLimit == 0, then
+// default limits are used for results.  WithWorkerPool can be provided with a
+// non-zero length slice of worker ids to restrict the returned workers to only
+// ones with the ids provided.
+func ListWorkers(ctx context.Context, reader db.Reader, scopeIds []string, opt ...Option) ([]*Worker, error) {
+	const op = "server.ListWorkers"
 	switch {
 	case len(scopeIds) == 0:
 		return nil, errors.New(ctx, errors.InvalidParameter, op, "no scope ids set")
@@ -215,14 +253,14 @@ func (r *Repository) ListWorkers(ctx context.Context, scopeIds []string, opt ...
 		whereArgs = append(whereArgs, opts.withWorkerPool)
 	}
 
-	limit := r.defaultLimit
+	limit := db.DefaultLimit
 	if opts.withLimit != 0 {
 		// non-zero signals an override of the default limit for the repo.
 		limit = opts.withLimit
 	}
 
 	var wAggs []*workerAggregate
-	if err := r.reader.SearchWhere(
+	if err := reader.SearchWhere(
 		ctx,
 		&wAggs,
 		strings.Join(where, " and "),