Cache docker container info for fast response times (500ms -> 1ms) (#18)

Simple cache in front of DockerContainerInfo

src/main/java/com/palantir/docker/proxy/CachingDockerContainerInfo.java

@@ -0,0 +1,64 @@
+/*
+ * Copyright 2017 Palantir Technologies, Inc. All rights reserved.
+ */
+
+package com.palantir.docker.proxy;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.cache.CacheBuilder;
+import com.google.common.cache.CacheLoader;
+import com.google.common.cache.LoadingCache;
+import java.util.Optional;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * CachingDockerContainerInfo will cache and refresh container info. If the refresh
+ * fails four times in a row, the entry will be removed and the next call will return
+ * the exception to you if it happens again.
+ */
+public class CachingDockerContainerInfo implements DockerContainerInfo {
+    private final DockerContainerInfo delegate;
+    private final LoadingCache<String, Optional<String>> ipForHostCache;
+    private final LoadingCache<String, Optional<String>> hostForIpCache;
+
+    public CachingDockerContainerInfo(DockerContainerInfo delegate) {
+        // It takes up to 1s to query docker so we set this to be under a multiple of 5, 10, and 15 by at least 2s
+        this(delegate, 53, TimeUnit.SECONDS);
+    }
+
+    @VisibleForTesting
+    CachingDockerContainerInfo(DockerContainerInfo delegate, long refreshDuration, TimeUnit refreshUnit) {
+        this.delegate = delegate;
+        this.ipForHostCache = CacheBuilder.newBuilder()
+                .expireAfterWrite(4 * refreshDuration, refreshUnit)
+                .refreshAfterWrite(refreshDuration, refreshUnit)
+                .build(CacheLoader.from(hostname -> delegate.getIpForHost(hostname)));
+        this.hostForIpCache = CacheBuilder.newBuilder()
+                .expireAfterWrite(4 * refreshDuration, refreshUnit)
+                .refreshAfterWrite(refreshDuration / 4, refreshUnit)
+                .build(CacheLoader.from(hostname -> delegate.getHostForIp(hostname)));
+    }
+
+    @Override
+    public Optional<String> getIpForHost(String hostname) {
+        Optional<String> ip = ipForHostCache.getUnchecked(hostname);
+        if (!ip.isPresent()) {
+            ipForHostCache.invalidate(hostname);
+        }
+        return ip;
+    }
+
+    @Override
+    public Optional<String> getHostForIp(String ip) {
+        Optional<String> host = hostForIpCache.getUnchecked(ip);
+        if (!host.isPresent()) {
+            hostForIpCache.invalidate(ip);
+        }
+        return host;
+    }
+
+    @Override
+    public String getNetworkName() {
+        return delegate.getNetworkName();
+    }
+}

src/main/java/com/palantir/docker/proxy/DockerContainerInfoUtils.java

@@ -113,7 +113,7 @@ public static List<String> getContainerIdsInDockerComposeProject(
     private static List<String> runDockerProcess(DockerExecutable docker, String... args)
             throws IOException, InterruptedException {
         Process process = docker.execute(args);
-        if (!process.waitFor(5, TimeUnit.SECONDS) || process.exitValue() != 0) {
+        if (!process.waitFor(15, TimeUnit.SECONDS) || process.exitValue() != 0) {
             throw new IllegalStateException("Unable to execute docker command: " + ImmutableList.copyOf(args));
         }
         return getLinesFromInputStream(process.getInputStream());

src/main/java/com/palantir/docker/proxy/DockerProxyRule.java

@@ -40,10 +40,11 @@ public class DockerProxyRule extends ExternalResource {
     public DockerProxyRule(
             Function<DockerExecutable, DockerContainerInfo> dockerContainerInfoCreator,
             Class<?> classToLogFor) {
-        this.dockerContainerInfo = dockerContainerInfoCreator.apply(DockerExecutable.builder()
+        DockerContainerInfo builtDockerContainerInfo = dockerContainerInfoCreator.apply(DockerExecutable.builder()
                 .dockerConfiguration(DockerMachine.localMachine().build())
                 .build());
         String logDirectory = DockerProxyRule.class.getSimpleName() + "-" + classToLogFor.getSimpleName();
+        this.dockerContainerInfo = new CachingDockerContainerInfo(builtDockerContainerInfo);
         this.dockerComposeRule = DockerComposeRule.builder()
                 .file(getDockerComposeFile(this.dockerContainerInfo.getNetworkName()).getPath())
                 .waitingForService("proxy", Container::areAllPortsOpen)

versions.props

@@ -1,4 +1,4 @@
-com.palantir.docker.compose:docker-compose-rule-junit4 = 0.33.0
+com.palantir.docker.compose:docker-compose-rule-junit4 = 0.34.0
 junit:junit = 4.12
 net.amygdalum:xrayinterface = 0.3.0
 one.util:streamex = 0.6.3