3 files changed, 62 insertions, 2 deletions

diff --git a/configutil/src/lib/configstatus.cpp b/configutil/src/lib/configstatus.cpp
index f889c436a97..76a1faec625 100644
--- a/configutil/src/lib/configstatus.cpp
+++ b/configutil/src/lib/configstatus.cpp
@@ -139,10 +139,14 @@ ConfigStatus::action()
 
     for (size_t i = 0; i < _cfg->hosts.size(); i++) {
         const cloud::config::ModelConfig::Hosts &hconf = _cfg->hosts[i];
+        // TODO PERF: don't fetch entire model when we're only looking for
+        // a subset of hosts.
+        if (!_flags.host_filter.includes(hconf.name)) {
+            continue;
+        }
 
         for (size_t j = 0; j < hconf.services.size(); j++) {
             const cloud::config::ModelConfig::Hosts::Services &svc = hconf.services[j];
-
             if (svc.type == "configserver") {
                 continue;
             }
diff --git a/configutil/src/lib/configstatus.h b/configutil/src/lib/configstatus.h
index 41e3d2fe782..0b168605d49 100644
--- a/configutil/src/lib/configstatus.h
+++ b/configutil/src/lib/configstatus.h
@@ -1,6 +1,7 @@
 // Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 #pragma once
 
+#include "hostfilter.h"
 #include <vespa/config-model.h>
 #include <vespa/vespalib/stllike/string.h>
 #include <vespa/config/config.h>
@@ -9,9 +10,15 @@ class ConfigStatus
 {
 public:
     struct Flags {
+        HostFilter host_filter;
         bool verbose;
         Flags()
-            : verbose(false)
+            : host_filter(), verbose(false)
+        {}
+
+        explicit Flags(const HostFilter& filter)
+            : host_filter(filter),
+              verbose(false)
         {}
     };
 
diff --git a/configutil/src/lib/hostfilter.h b/configutil/src/lib/hostfilter.h
new file mode 100644
index 00000000000..8c255c930cc
--- /dev/null
+++ b/configutil/src/lib/hostfilter.h
@@ -0,0 +1,49 @@
+// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+#pragma once
+
+#include <unordered_set>
+#include <string>
+
+/**
+ * Simple host filter which in its default empty state implicitly includes all
+ * hosts, or only an explicit subset iff at least one host has been provided
+ * to the filter as part of construction.
+ */
+class HostFilter {
+public:
+    using HostSet = std::unordered_set<std::string>;
+private:
+    HostSet _hosts;
+public:
+    /**
+     * Empty host filter; all hosts are implicitly included.
+     */
+    HostFilter() : _hosts() {}
+
+    /**
+     * Explicitly given host set; only the hosts whose name exactly match
+     * one of the provided names will pass the includes(name) check.
+     */
+    explicit HostFilter(const std::unordered_set<std::string>& hosts)
+        : _hosts(hosts)
+    {
+    }
+
+    explicit HostFilter(std::unordered_set<std::string>&& hosts)
+        : _hosts(std::move(hosts))
+    {
+    }
+
+    HostFilter(HostFilter&&) = default;
+    HostFilter& operator=(HostFilter&&) = default;
+
+    HostFilter(const HostFilter&) = default;
+    HostFilter& operator=(const HostFilter&) = default;
+
+    bool includes(const std::string& candidate) const {
+        if (_hosts.empty()) {
+            return true;
+        }
+        return (_hosts.find(candidate) != _hosts.end());
+    }
+};