Github user neykov commented on a diff in the pull request:
https://github.com/apache/brooklyn-server/pull/564#discussion_r103455492
--- Diff:
core/src/main/java/org/apache/brooklyn/feed/AbstractCommandFeed.java ---
@@ -0,0 +1,260 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.brooklyn.feed;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.Callable;
+import java.util.concurrent.TimeUnit;
+
+import org.apache.brooklyn.api.entity.Entity;
+import org.apache.brooklyn.api.entity.EntityLocal;
+import org.apache.brooklyn.api.location.MachineLocation;
+import org.apache.brooklyn.config.ConfigKey;
+import org.apache.brooklyn.core.config.ConfigKeys;
+import org.apache.brooklyn.core.feed.AbstractFeed;
+import org.apache.brooklyn.core.feed.AttributePollHandler;
+import org.apache.brooklyn.core.feed.DelegatingPollHandler;
+import org.apache.brooklyn.core.feed.Poller;
+import org.apache.brooklyn.core.location.Locations;
+import org.apache.brooklyn.feed.ssh.SshPollValue;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.apache.brooklyn.util.time.Duration;
+
+import com.google.common.base.Objects;
+import com.google.common.base.Supplier;
+import com.google.common.base.Suppliers;
+import com.google.common.collect.HashMultimap;
+import com.google.common.collect.SetMultimap;
+import com.google.common.collect.Sets;
+import com.google.common.reflect.TypeToken;
+
+/**
+ * Provides a feed of attribute values, by polling over ssh.
+ *
+ * Example usage (e.g. in an entity that extends SoftwareProcessImpl):
+ * <pre>
+ * {@code
+ * private SshFeed feed;
+ *
+ * //@Override
+ * protected void connectSensors() {
+ * super.connectSensors();
+ *
+ * feed = SshFeed.builder()
+ * .entity(this)
+ * .machine(mySshMachineLachine)
+ * .poll(new CommandPollConfig<Boolean>(SERVICE_UP)
+ * .command("rabbitmqctl -q status")
+ * .onSuccess(new Function<SshPollValue, Boolean>() {
+ * public Boolean apply(SshPollValue input) {
+ * return (input.getExitStatus() == 0);
+ * }}))
+ * .build();
+ * }
+ *
+ * {@literal @}Override
+ * protected void disconnectSensors() {
+ * super.disconnectSensors();
+ * if (feed != null) feed.stop();
+ * }
+ * }
+ * </pre>
+ *
+ * @author aled
+ */
+public abstract class AbstractCommandFeed extends AbstractFeed {
+
+ public static final Logger log =
LoggerFactory.getLogger(AbstractCommandFeed.class);
+
+ @SuppressWarnings("serial")
+ public static final ConfigKey<Supplier<MachineLocation>> MACHINE =
ConfigKeys.newConfigKey(
+ new TypeToken<Supplier<MachineLocation>>() {},
+ "machine");
+
+ public static final ConfigKey<Boolean> EXEC_AS_COMMAND =
ConfigKeys.newBooleanConfigKey("execAsCommand");
+
+ @SuppressWarnings("serial")
+ public static final ConfigKey<SetMultimap<SshPollIdentifier,
CommandPollConfig<?>>> POLLS = ConfigKeys.newConfigKey(
+ new TypeToken<SetMultimap<SshPollIdentifier,
CommandPollConfig<?>>>() {},
+ "polls");
+
+ public static abstract class Builder<T extends AbstractCommandFeed, B
extends Builder<T, B>> {
+ private Entity entity;
+ private boolean onlyIfServiceUp = false;
+ private Supplier<MachineLocation> machine;
+ private Duration period = Duration.of(500, TimeUnit.MILLISECONDS);
+ private boolean execAsCommand = false;
+ private String uniqueTag;
+ private volatile boolean built;
+
+ public B entity(Entity val) {
+ this.entity = val;
+ return self();
+ }
+ public B onlyIfServiceUp() { return onlyIfServiceUp(true); }
+ public B onlyIfServiceUp(boolean onlyIfServiceUp) {
+ this.onlyIfServiceUp = onlyIfServiceUp;
+ return self();
+ }
+ /** optional, to force a machine; otherwise it is inferred from
the entity */
+ public B machine(MachineLocation val) { return
machine(Suppliers.ofInstance(val)); }
+ /** optional, to force a machine; otherwise it is inferred from
the entity */
+ public B machine(Supplier<MachineLocation> val) {
+ this.machine = val;
+ return self();
+ }
+ public B period(Duration period) {
+ this.period = period;
+ return self();
+ }
+ public B period(long millis) {
+ return period(Duration.of(millis, TimeUnit.MILLISECONDS));
+ }
+ public B period(long val, TimeUnit units) {
+ return period(Duration.of(val, units));
+ }
+ public abstract B poll(CommandPollConfig<?> config);
+ public abstract List<CommandPollConfig<?>> getPolls();
+
+ public B execAsCommand() {
+ execAsCommand = true;
+ return self();
+ }
+ public B execAsScript() {
+ execAsCommand = false;
+ return self();
+ }
+ public B uniqueTag(String uniqueTag) {
+ this.uniqueTag = uniqueTag;
+ return self();
+ }
+
+ protected abstract B self();
+
+ protected abstract T instantiateFeed();
+
+ public T build() {
+ built = true;
+ T result = instantiateFeed();
+ result.setEntity(checkNotNull((EntityLocal)entity, "entity"));
+ result.start();
+ return result;
+ }
+
+ @Override
+ protected void finalize() {
+ if (!built) log.warn("SshFeed.Builder created, but build()
never called");
+ }
+ }
+
+ private static class SshPollIdentifier {
+ final Supplier<String> command;
+ final Supplier<Map<String, String>> env;
+
+ private SshPollIdentifier(Supplier<String> command,
Supplier<Map<String, String>> env) {
+ this.command = checkNotNull(command, "command");
+ this.env = checkNotNull(env, "env");
+ }
+
+ @Override
+ public int hashCode() {
+ return Objects.hashCode(command, env);
+ }
+
+ @Override
+ public boolean equals(Object other) {
+ if (!(other instanceof SshPollIdentifier)) {
+ return false;
+ }
+ SshPollIdentifier o = (SshPollIdentifier) other;
+ return Objects.equal(command, o.command) &&
+ Objects.equal(env, o.env);
+ }
+ }
+
+ /**
+ * For rebind; do not call directly; use builder
+ */
+ public AbstractCommandFeed() {
+ }
+
+ protected AbstractCommandFeed(final Builder builder) {
+ config().set(ONLY_IF_SERVICE_UP, builder.onlyIfServiceUp);
+ config().set(MACHINE, builder.machine);
+ config().set(EXEC_AS_COMMAND, builder.execAsCommand);
+
+ SetMultimap<SshPollIdentifier, CommandPollConfig<?>> polls =
HashMultimap.<SshPollIdentifier,CommandPollConfig<?>>create();
+ for (CommandPollConfig<?> config :
(List<CommandPollConfig<?>>)builder.getPolls()) {
+ @SuppressWarnings({ "unchecked", "rawtypes" })
+ CommandPollConfig<?> configCopy = new
CommandPollConfig(config);
+ if (configCopy.getPeriod() < 0)
configCopy.period(builder.period);
+ polls.put(new SshPollIdentifier(config.getCommandSupplier(),
config.getEnvSupplier()), configCopy);
+ }
+ config().set(POLLS, polls);
+ initUniqueTag(builder.uniqueTag, polls.values());
+ }
+
+ protected MachineLocation getMachine() {
+ Supplier<MachineLocation> supplier = config().get(MACHINE);
+ if (supplier != null) {
+ return supplier.get();
+ } else {
+ return
Locations.findUniqueMachineLocation(entity.getLocations()).get();
+ }
+ }
+
+ @Override
+ protected void preStart() {
+ SetMultimap<SshPollIdentifier, CommandPollConfig<?>> polls =
config().get(POLLS);
+
+ for (final SshPollIdentifier pollInfo : polls.keySet()) {
+ Set<CommandPollConfig<?>> configs = polls.get(pollInfo);
+ long minPeriod = Integer.MAX_VALUE;
+ Set<AttributePollHandler<? super SshPollValue>> handlers =
Sets.newLinkedHashSet();
+
+ for (CommandPollConfig<?> config : configs) {
+ handlers.add(new
AttributePollHandler<SshPollValue>(config, entity, this));
+ if (config.getPeriod() > 0) minPeriod =
Math.min(minPeriod, config.getPeriod());
+ }
+
+ getPoller().scheduleAtFixedRate(
+ new Callable<SshPollValue>() {
+ @Override
+ public SshPollValue call() throws Exception {
+ return exec(pollInfo.command.get(),
pollInfo.env.get());
+ }},
+ new DelegatingPollHandler<SshPollValue>(handlers),
+ minPeriod);
+ }
+ }
+
+ @Override
+ @SuppressWarnings("unchecked")
+ protected Poller<SshPollValue> getPoller() {
+ return (Poller<SshPollValue>) super.getPoller();
+ }
+
+ protected abstract SshPollValue exec(String command,
Map<String,String> env) throws IOException;
--- End diff --
`SshPollValue` is again ssh specific. Could include it as a generic type.
Alternatively could deprecate it in favour of more generic name.
I'm fine leaving it as is though.
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