Allow all application hosts to talk to ZooKeeper

5 files changed, 72 insertions, 91 deletions

diff --git a/config-model/src/main/java/com/yahoo/config/model/provision/Host.java b/config-model/src/main/java/com/yahoo/config/model/provision/Host.java
index afe4de7ef0d..360853d0f79 100644
--- a/config-model/src/main/java/com/yahoo/config/model/provision/Host.java
+++ b/config-model/src/main/java/com/yahoo/config/model/provision/Host.java
@@ -1,40 +1,39 @@
 // Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.config.model.provision;
 
+import com.google.common.collect.ImmutableList;
+
 import java.util.ArrayList;
 import java.util.List;
 
 /**
- * A hostname with zero or more aliases.
+ * A hostname with zero or more aliases. This is immutable.
  *
  * @author hmusum
  */
 public class Host {
 
     private final String hostname;
-    private final List<String> hostAliases;
+    private final ImmutableList<String> aliases;
 
     public Host(String hostname) {
         this.hostname = hostname;
-        this.hostAliases = new ArrayList<>();
+        this.aliases = ImmutableList.of();
     }
 
     public Host(String hostname, List<String> hostAliases) {
         this.hostname = hostname;
-        this.hostAliases = hostAliases;
+        this.aliases = ImmutableList.copyOf(hostAliases);
     }
 
-    public String getHostname() {
-        return hostname;
-    }
+    public String hostname() { return hostname; }
 
-    public List<String> getHostAliases() {
-        return hostAliases;
-    }
+    /** Returns an immutable list of the aliases of this node, which may be empty but never null */
+    public List<String> aliases() { return aliases; }
 
     @Override
     public String toString() {
-        return hostname + " (aliases: " + hostAliases + ")";
+        return hostname + (aliases.size() > 0 ? " (aliases: " + aliases + ")" : "" );
     }
 
 }
diff --git a/config-model/src/main/java/com/yahoo/config/model/provision/Hosts.java b/config-model/src/main/java/com/yahoo/config/model/provision/Hosts.java
index bfb77612d31..1a145e6c83e 100644
--- a/config-model/src/main/java/com/yahoo/config/model/provision/Hosts.java
+++ b/config-model/src/main/java/com/yahoo/config/model/provision/Hosts.java
@@ -1,8 +1,9 @@
 // Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.config.model.provision;
 
+import com.google.common.collect.ImmutableMap;
+import com.yahoo.cloud.config.ConfigserverConfig;
 import com.yahoo.config.model.builder.xml.XmlHelper;
-import com.yahoo.log.LogLevel;
 import com.yahoo.net.HostName;
 import com.yahoo.text.XML;
 import com.yahoo.vespa.model.builder.xml.dom.VespaDomBuilder;
@@ -17,26 +18,60 @@ import java.util.*;
 import java.util.logging.Logger;
 
 /**
- * TODO: What is this?
+ * A collection of hosts
  *
- * @author hmusum
+ * @author bratseth
  */
 public class Hosts {
 
     public static final Logger log = Logger.getLogger(Hosts.class.getPackage().toString());
 
-    private final HashMap<String, Host> hosts = new LinkedHashMap<>();
-    private final Map<String, String> alias2hostname = new LinkedHashMap<>();
-    private final Map<String, Host> alias2host = new LinkedHashMap<>();
+    private final ImmutableMap<String, Host> hosts;
 
+    public Hosts(Collection<Host> hosts) {
+        validateAliases(hosts);
+        
+        ImmutableMap.Builder<String, Host> hostsBuilder = new ImmutableMap.Builder<>();
+        for (Host host : hosts)
+            hostsBuilder.put(host.hostname(), host);
+        this.hosts = hostsBuilder.build();
+
+        System.setProperty("zookeeper.vespa.clients", toHostnameString(hosts)); // See com.yahoo.vespa.zookeeper.ZooKeeperServer
+    }
+
+    /** Throw IllegalArgumentException if host aliases breaks invariants */
+    private void validateAliases(Collection<Host> hosts) {
+        Set<String> aliases = new HashSet<>();
+        for (Host host : hosts) {
+            if (host.aliases().size() > 0) {
+                if (host.aliases().size() < 1)
+                    throw new IllegalArgumentException("Host '" + host.hostname() + "' must have at least one <alias> tag.");
+                for (String alias : host.aliases()) {
+                    if (aliases.contains(alias))
+                        throw new IllegalArgumentException("Alias '" + alias + "' is used by multiple hosts.");
+                    aliases.add(alias);
+                }
+            }
+        }
+    }
+    
+    private String toHostnameString(Collection<Host> hosts) {
+        StringBuilder b = new StringBuilder();
+        for (Host host : hosts)
+            b.append(host.hostname()).append(",");
+        if (b.length() > 0)
+            b.setLength(b.length() - 1); // remove last comma
+        return b.toString();
+    }
+    
     /**
      * Builds host system from a hosts.xml file
      *
      * @param hostsFile a reader for host from application package
      * @return the HostSystem for this application package
      */
-    public static Hosts getHosts(Reader hostsFile) {
-        Hosts hosts = new Hosts();
+    public static Hosts readFrom(Reader hostsFile) {
+        List<Host> hosts = new ArrayList<>();
         Document doc;
         try {
             doc = XmlHelper.getDocumentBuilder().parse(new InputSource(hostsFile));
@@ -55,62 +90,13 @@ public class Hosts {
             if (hostAliases.isEmpty()) {
                 throw new IllegalArgumentException("No host aliases defined for host '" + name + "'");
             }
-            Host host = new Host(name, hostAliases);
-            hosts.addHost(host, hostAliases);
-        }
-        log.log(LogLevel.DEBUG, "Created hosts:" + hosts);
-        return hosts;
-    }
-
-    public Collection<Host> getHosts() {
-        return hosts.values();
-    }
-
-    /**
-     * Adds one host to this host system.
-     *
-     * @param host    The host to add
-     * @param aliases The aliases for this host.
-     */
-    public void addHost(Host host, List<String> aliases) {
-        hosts.put(host.getHostname(), host);
-        if ((aliases != null) && (aliases.size() > 0)) {
-            addHostAliases(aliases, host);
+            hosts.add(new Host(name, hostAliases));
         }
+        return new Hosts(hosts);
     }
 
-    /**
-     * Add all aliases for one host
-     *
-     * @param hostAliases A list of host aliases
-     * @param host        The Host instance to add the alias for
-     */
-    private void addHostAliases(List<String> hostAliases, Host host) {
-        if (hostAliases.size() < 1) {
-            throw new RuntimeException("Host '" + host.getHostname() + "' must have at least one <alias> tag.");
-        }
-        for (String alias : hostAliases) {
-            addHostAlias(alias, host);
-        }
-    }
-
-    /**
-     * Adds an alias for the given host
-     *
-     * @param alias alias (string) for a Host
-     * @param host  the {@link Host} to add the alias for
-     */
-    protected void addHostAlias(String alias, Host host) {
-        if (alias2hostname.containsKey(alias)) {
-            throw new RuntimeException("Alias '" + alias + "' must be used for only one host!");
-        }
-        alias2hostname.put(alias, host.getHostname());
-        alias2host.put(alias, host);
-    }
-
-    public Map<String, Host> getAlias2host() {
-        return alias2host;
-    }
+    /** Returns an immutable collection of the hosts of this */
+    public Collection<Host> asCollection() { return hosts.values(); }
 
     @Override
     public String toString() {
diff --git a/config-model/src/main/java/com/yahoo/config/model/provision/HostsXmlProvisioner.java b/config-model/src/main/java/com/yahoo/config/model/provision/HostsXmlProvisioner.java
index bf630b74272..32a7e79d278 100644
--- a/config-model/src/main/java/com/yahoo/config/model/provision/HostsXmlProvisioner.java
+++ b/config-model/src/main/java/com/yahoo/config/model/provision/HostsXmlProvisioner.java
@@ -22,27 +22,24 @@ public class HostsXmlProvisioner implements HostProvisioner {
     public static final String IMPLICIT_ADMIN_HOSTALIAS = "INTERNAL_VESPA_IMPLICIT_ADMIN";
 
     public HostsXmlProvisioner(Reader hosts) {
-        this.hosts = Hosts.getHosts(hosts);
+        this.hosts = Hosts.readFrom(hosts);
     }
 
     @Override
     public HostSpec allocateHost(String alias) {
-        /**
-         * Some special rules to allow no admin elements as well
-         * as jdisc element without nodes.
-         */
+        // Some special rules to allow no admin elements as well as jdisc element without nodes.
         if (alias.equals(IMPLICIT_ADMIN_HOSTALIAS)) {
-            if (hosts.getHosts().size() > 1) {
-                throw new IllegalArgumentException("More than 1 host specified (" + hosts.getHosts().size() + ") and <admin> not specified");
+            if (hosts.asCollection().size() > 1) {
+                throw new IllegalArgumentException("More than 1 host specified (" + hosts.asCollection().size() + ") and <admin> not specified");
             } else {
                 return host2HostSpec(getFirstHost());
             }
         } else if (alias.equals(Container.SINGLENODE_CONTAINER_SERVICESPEC)) {
             return host2HostSpec(getFirstHost());
         }
-        for (Host host : hosts.getHosts()) {
-            if (host.getHostAliases().contains(alias)) {
-                return new HostSpec(host.getHostname(), host.getHostAliases());
+        for (Host host : hosts.asCollection()) {
+            if (host.aliases().contains(alias)) {
+                return new HostSpec(host.hostname(), host.aliases());
             }
         }
         throw new IllegalArgumentException("Unable to find host for alias '" + alias + "'");
@@ -54,11 +51,11 @@ public class HostsXmlProvisioner implements HostProvisioner {
     }
 
     private HostSpec host2HostSpec(Host host) {
-        return new HostSpec(host.getHostname(), host.getHostAliases());
+        return new HostSpec(host.hostname(), host.aliases());
     }
 
     private Host getFirstHost() {
-        return hosts.getHosts().iterator().next();
+        return hosts.asCollection().iterator().next();
     }
 
 }
diff --git a/config-model/src/main/java/com/yahoo/config/model/provision/InMemoryProvisioner.java b/config-model/src/main/java/com/yahoo/config/model/provision/InMemoryProvisioner.java
index b4488cef385..c0813f7ab85 100644
--- a/config-model/src/main/java/com/yahoo/config/model/provision/InMemoryProvisioner.java
+++ b/config-model/src/main/java/com/yahoo/config/model/provision/InMemoryProvisioner.java
@@ -49,12 +49,12 @@ public class InMemoryProvisioner implements HostProvisioner {
 
     /** Creates this with a set of hosts of the flavor 'default' */
     public InMemoryProvisioner(Hosts hosts, boolean failOnOutOfCapacity, String ... retiredHostNames) {
-        this(Collections.singletonMap("default", hosts.getHosts()), failOnOutOfCapacity, 0, retiredHostNames);
+        this(Collections.singletonMap("default", hosts.asCollection()), failOnOutOfCapacity, 0, retiredHostNames);
     }
 
     /** Creates this with a set of hosts of the flavor 'default' */
     public InMemoryProvisioner(Hosts hosts, boolean failOnOutOfCapacity, int startIndexForClusters, String ... retiredHostNames) {
-        this(Collections.singletonMap("default", hosts.getHosts()), failOnOutOfCapacity, startIndexForClusters, retiredHostNames);
+        this(Collections.singletonMap("default", hosts.asCollection()), failOnOutOfCapacity, startIndexForClusters, retiredHostNames);
     }
 
     public InMemoryProvisioner(Map<String, Collection<Host>> hosts, boolean failOnOutOfCapacity, int startIndexForClusters, String ... retiredHostNames) {
@@ -88,7 +88,7 @@ public class InMemoryProvisioner implements HostProvisioner {
         List<Host> defaultHosts = freeNodes.get("default");
         if (defaultHosts.isEmpty()) throw new IllegalArgumentException("No more hosts of default flavor available");
         Host newHost = freeNodes.removeValue("default", 0);
-        HostSpec hostSpec = new HostSpec(newHost.getHostname(), newHost.getHostAliases());
+        HostSpec hostSpec = new HostSpec(newHost.hostname(), newHost.aliases());
         legacyMapping.put(alias, hostSpec);
         return hostSpec;
     }
@@ -141,7 +141,7 @@ public class InMemoryProvisioner implements HostProvisioner {
             if (freeNodes.get(flavor).isEmpty()) throw new IllegalArgumentException("No nodes of flavor '" + flavor + "' available");
             Host newHost = freeNodes.removeValue(flavor, 0);
             ClusterMembership membership = ClusterMembership.from(clusterGroup, nextIndex++);
-            allocation.add(new HostSpec(newHost.getHostname(), newHost.getHostAliases(), membership));
+            allocation.add(new HostSpec(newHost.hostname(), newHost.aliases(), membership));
         }
         nextIndexInCluster.put(new Pair<>(clusterGroup.type(), clusterGroup.id()), nextIndex);
 
diff --git a/config-model/src/main/java/com/yahoo/config/model/provision/SingleNodeProvisioner.java b/config-model/src/main/java/com/yahoo/config/model/provision/SingleNodeProvisioner.java
index 67e80ec95d6..1d5544873d9 100644
--- a/config-model/src/main/java/com/yahoo/config/model/provision/SingleNodeProvisioner.java
+++ b/config-model/src/main/java/com/yahoo/config/model/provision/SingleNodeProvisioner.java
@@ -1,7 +1,6 @@
 // Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.config.model.provision;
 
-import com.yahoo.config.application.api.DeployLogger;
 import com.yahoo.config.model.api.HostProvisioner;
 import com.yahoo.config.provision.*;
 import com.yahoo.net.HostName;
@@ -31,7 +30,7 @@ public class SingleNodeProvisioner implements HostProvisioner {
         } catch (UnknownHostException e) {
             throw new RuntimeException(e);
         }
-        this.hostSpec = new HostSpec(host.getHostname(), host.getHostAliases());
+        this.hostSpec = new HostSpec(host.hostname(), host.aliases());
     }
 
     @Override
@@ -42,7 +41,7 @@ public class SingleNodeProvisioner implements HostProvisioner {
     @Override
     public List<HostSpec> prepare(ClusterSpec cluster, Capacity capacity, int groups, ProvisionLogger logger) { // TODO: This should fail if capacity requested is more than 1
         List<HostSpec> hosts = new ArrayList<>();
-        hosts.add(new HostSpec(host.getHostname(), host.getHostAliases(), ClusterMembership.from(cluster, counter++)));
+        hosts.add(new HostSpec(host.hostname(), host.aliases(), ClusterMembership.from(cluster, counter++)));
         return hosts;
     }