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Merged
merged 1 commit into from
Mar 9, 2021
Merged

Refactor the DiskLRU Cache into its own class #32

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140 changes: 41 additions & 99 deletions src/main/java/co/zeroae/gate/App.java
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Original file line number Diff line number Diff line change
Expand Up @@ -8,20 +8,16 @@

import com.amazonaws.util.Base64;
import com.amazonaws.xray.AWSXRay;
import com.amazonaws.xray.entities.Subsegment;

import gate.*;
import gate.creole.ResourceInstantiationException;
import gate.util.GateException;
import gate.util.persistence.PersistenceManager;

import com.jakewharton.disklrucache.DiskLruCache;

import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;

import javax.xml.stream.XMLStreamException;
import java.io.*;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLStreamHandler;
import java.util.*;
Expand Down Expand Up @@ -56,8 +52,8 @@ public class App implements RequestHandler<APIGatewayProxyRequestEvent, APIGatew
"Gate Exporters", Utils::loadExporters
);

private static final DiskLruCache cache = AWSXRay.createSegment(
"Cache Init", App::initializeCache);
private static final DocumentLRUCache cache = AWSXRay.createSegment("Cache Init",
() -> new DocumentLRUCache(App.CACHE_DIR, App.CACHE_DIR_USAGE));

private static final URLStreamHandler b64Handler = new Handler();

Expand All @@ -75,60 +71,28 @@ public APIGatewayProxyResponseEvent handleRequest(APIGatewayProxyRequestEvent in
}
return null;
}).get();
final DocumentExporter exporter = exporters.get(responseType);
if (exporter == null) {
throw new IOException("Unsupported response content type.");
}
if (responseType != null)
response.getHeaders().put("Content-Type", responseType.split(";")[0].trim());

final DocumentExporter exporter = exporters.get(responseType);
if (exporter == null)
throw new IOException("Unsupported response content type.");


final FeatureMap featureMap = Factory.newFeatureMap();
final String bodyType = input.getHeaders().getOrDefault("Content-Type", "text/plain");
final String inputDigest = AWSXRay.createSubsegment("Message Digest",() -> {
String rv = Utils.computeMessageDigest(bodyType, input.getBody());
final String contentType = input.getHeaders().getOrDefault("Content-Type", "text/plain");
final String contentDigest = AWSXRay.createSubsegment("Message Digest",() -> {
String rv = Utils.computeMessageDigest(contentType, input.getBody());
AWSXRay.getCurrentSubsegment().putMetadata("SHA256", rv);
return rv;
});

featureMap.put(Document.DOCUMENT_MIME_TYPE_PARAMETER_NAME, bodyType);
if (!input.getIsBase64Encoded())
featureMap.put(Document.DOCUMENT_STRING_CONTENT_PARAMETER_NAME, input.getBody());
else {
// GATE FastInfosetFormat can not handle binary in the string content.
Handler.paths.put(inputDigest, input.getBody());
featureMap.put(
Document.DOCUMENT_URL_PARAMETER_NAME,
new URL("b64",
bodyType != null ? Base64.encodeAsString(bodyType.getBytes()) : null,
64,
inputDigest,
b64Handler));
}
putRequestBody(featureMap, contentType, contentDigest, input.getBody(), input.getIsBase64Encoded());

response.getHeaders().put("x-zae-gate-cache", "HIT");
final Document doc = cacheComputeIfNull(
inputDigest,
() -> {
final Subsegment subsegment = AWSXRay.beginSubsegment("Gate Execute");
final Corpus corpus = application.getCorpus();
final Document rv = (Document)Factory.createResource(
"gate.corpora.DocumentImpl",
featureMap
);
response.getHeaders().put("x-zae-gate-cache", "MISS");
try {
corpus.add(rv);
application.execute();
} catch (GateException e) {
subsegment.addException(e);
throw e;
} finally {
corpus.clear();
AWSXRay.endSubsegment();
}
return rv;
}
);
final Document doc = cache.computeIfNull(contentDigest, () -> {
response.getHeaders().put("x-zae-gate-cache", "MISS");
return execute(featureMap);
});
AWSXRay.beginSubsegment("Gate Export");
AWSXRay.getCurrentSubsegment().putMetadata("Content-Type", response.getHeaders().get("Content-Type"));
try {
Expand All @@ -152,41 +116,36 @@ public APIGatewayProxyResponseEvent handleRequest(APIGatewayProxyRequestEvent in
}
}

private void cachePutDocument(String key, Document doc) {
try {
DiskLruCache.Editor editor = cache.edit(key);
editor.set(0, doc.toXml());
editor.commit();
} catch (IOException e) {
logger.warn(e);
AWSXRay.getCurrentSubsegment().addException(e);
private void putRequestBody(FeatureMap featureMap, String mimeType, String contentDigest, String content, boolean isBase64Encoded) throws MalformedURLException {
featureMap.put(Document.DOCUMENT_MIME_TYPE_PARAMETER_NAME, mimeType);
if (!isBase64Encoded)
featureMap.put(Document.DOCUMENT_STRING_CONTENT_PARAMETER_NAME, content);
else {
// GATE FastInfosetFormat can not handle binary in the string content.
Handler.paths.put(contentDigest, content);
featureMap.put(
Document.DOCUMENT_URL_PARAMETER_NAME,
new URL("b64",
mimeType != null ? Base64.encodeAsString(mimeType.getBytes()) : null,
64,
contentDigest,
b64Handler));
}
}

private Document cacheComputeIfNull(String key, Utils.TextProcessor processor) throws GateException {
private Document execute(FeatureMap docFeatureMap) throws GateException {
AWSXRay.beginSubsegment("Gate Execute");
try {
final DiskLruCache.Snapshot snapshot = cache.get(key);
if (snapshot == null) {
final Document doc = processor.process();
AWSXRay.createSubsegment("Cache Edit", () -> cachePutDocument(key, doc));
return doc;
} else {
AWSXRay.beginSubsegment("Cache Read");
try {
return Utils.xmlToDocument(new InputStreamReader(snapshot.getInputStream(0)));
} catch (ResourceInstantiationException | XMLStreamException e) {
logger.warn(e);
AWSXRay.getCurrentSubsegment().addException(e);
cache.remove(key);
return processor.process();
} finally {
AWSXRay.endSubsegment();
}
}
} catch (IOException e) {
logger.warn(e);
final Document rv = (Document) Factory.createResource("gate.corpora.DocumentImpl", docFeatureMap);
application.getCorpus().add(rv);
application.execute();
return rv;
} catch (GateException e) {
AWSXRay.getCurrentSubsegment().addException(e);
return processor.process();
throw e;
} finally {
application.getCorpus().clear();
AWSXRay.endSubsegment();
}
}

Expand Down Expand Up @@ -242,21 +201,4 @@ private static CorpusController loadApplication() {
}
}

private static DiskLruCache initializeCache() {
File cacheDir = new File(CACHE_DIR);
if (!cacheDir.exists() && !cacheDir.mkdirs()) {
throw new RuntimeException("Unable to create cache directory '" + cacheDir.getName() + "'.");
}
for (File file: Objects.requireNonNull(cacheDir.listFiles())) file.delete();
try {
long usableSpace = (long) (cacheDir.getUsableSpace()*CACHE_DIR_USAGE);
return DiskLruCache.open(cacheDir,
1,
1,
usableSpace);
} catch (IOException e) {
throw new RuntimeException(e);
}
}

}
91 changes: 91 additions & 0 deletions src/main/java/co/zeroae/gate/DocumentLRUCache.java
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Original file line number Diff line number Diff line change
@@ -0,0 +1,91 @@
package co.zeroae.gate;

import com.amazonaws.xray.AWSXRay;
import com.jakewharton.disklrucache.DiskLruCache;
import gate.Document;
import gate.creole.ResourceInstantiationException;
import gate.util.GateException;
import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;

import javax.xml.stream.XMLStreamException;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Objects;

class DocumentLRUCache {
private static final int VERSION = 1;
private static final int VALUE_COUNT = 1;

private static final Logger logger = LogManager.getLogger(DocumentLRUCache.class);

private final DiskLruCache cache;

DocumentLRUCache(String cacheDir, double maxUsage) {
cache = initializeCache(cacheDir, maxUsage);
}

public Document computeIfNull(String key, Utils.GATESupplier<Document> supplier) throws GateException {
Document rv = get(key);
if (rv == null) {
rv = supplier.get();
put(key, rv);
}
return rv;
}

public Document get(String key) {
AWSXRay.beginSubsegment("Cache Read");
try {
final DiskLruCache.Snapshot snapshot = cache.get(key);
if (snapshot != null) {
AWSXRay.beginSubsegment("Deserialize");
try {
return Utils.xmlToDocument(new InputStreamReader(snapshot.getInputStream(0)));
} catch (ResourceInstantiationException | XMLStreamException e) {
logger.warn(e);
AWSXRay.getCurrentSubsegment().addException(e);
cache.remove(key);
return null;
} finally {
AWSXRay.endSubsegment();
}
} else
return null;
} catch (IOException e) {
logger.warn(e);
return null;
} finally {
AWSXRay.endSubsegment();
}
}

public void put(String key, Document doc) {
AWSXRay.beginSubsegment("Cache Edit");
try {
DiskLruCache.Editor editor = cache.edit(key);
editor.set(0, doc.toXml());
editor.commit();
} catch (IOException e) {
logger.warn(e);
AWSXRay.getCurrentSubsegment().addException(e);
} finally {
AWSXRay.endSubsegment();
}
}

private static DiskLruCache initializeCache(String cacheDir, double maxUsage) {
File cacheDirPath = new File(cacheDir);
if (!cacheDirPath.exists() && !cacheDirPath.mkdirs()) {
throw new RuntimeException("Unable to create cache directory '" + cacheDirPath.getName() + "'.");
}
for (File file: Objects.requireNonNull(cacheDirPath.listFiles())) file.delete();
try {
long usableSpace = (long) (cacheDirPath.getUsableSpace()*maxUsage);
return DiskLruCache.open(cacheDirPath, VERSION, VALUE_COUNT, usableSpace);
} catch (IOException e) {
throw new RuntimeException(e);
}
}
}
5 changes: 3 additions & 2 deletions src/main/java/co/zeroae/gate/Utils.java
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Original file line number Diff line number Diff line change
Expand Up @@ -18,8 +18,9 @@

public class Utils {

interface TextProcessor {
Document process() throws GateException;
@FunctionalInterface
interface GATESupplier<T> {
T get() throws GateException;
}

/**
Expand Down