Add compressor SPI to support additional compression algos

exporters/common/src/main/java/io/opentelemetry/exporter/internal/compression/Compressor.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.exporter.internal.compression;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import javax.annotation.concurrent.ThreadSafe;
+
+/**
+ * An abstraction for compressing messages. Implementation MUST be thread safe as the same instance
+ * is expected to be used many times and concurrently. Instances are usually singletons.
+ *
+ * <p>This class is internal and is hence not for public use. Its APIs are unstable and can change
+ * at any time.
+ */
+@ThreadSafe
+public interface Compressor {
+
+  /**
+   * The name of the compressor encoding.
+   *
+   * <p>Used to identify the compressor during configuration and to populate the {@code
+   * Content-Encoding} header.
+   */
+  String getEncoding();
+
+  /** Wrap the {@code outputStream} with a compressing output stream. */
+  OutputStream compress(OutputStream outputStream) throws IOException;
+}

exporters/common/src/main/java/io/opentelemetry/exporter/internal/compression/CompressorProvider.java

@@ -0,0 +1,18 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.exporter.internal.compression;
+
+/**
+ * A service provider interface (SPI) for providing {@link Compressor}s.
+ *
+ * <p>This class is internal and is hence not for public use. Its APIs are unstable and can change
+ * at any time.
+ */
+public interface CompressorProvider {
+
+  /** Return the {@link Compressor}. */
+  Compressor getInstance();
+}

exporters/common/src/main/java/io/opentelemetry/exporter/internal/compression/CompressorUtil.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.exporter.internal.compression;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.ServiceLoader;
+import java.util.Set;
+
+/**
+ * Utilities for resolving SPI {@link Compressor}s.
+ *
+ * <p>This class is internal and is hence not for public use. Its APIs are unstable and can change
+ * at any time.
+ *
+ * @see CompressorProvider
+ */
+public final class CompressorUtil {
+
+  private static final Map<String, Compressor> compressorRegistry = buildCompressorRegistry();
+
+  private CompressorUtil() {}
+
+  /** Get list of loaded compressors, named according to {@link Compressor#getEncoding()}. */
+  public static Set<String> supportedCompressors() {
+    return Collections.unmodifiableSet(compressorRegistry.keySet());
+  }
+
+  /**
+   * Resolve the {@link Compressor} with the {@link Compressor#getEncoding()} equal to the {@code
+   * encoding}.
+   *
+   * @throws IllegalArgumentException if no match is found
+   */
+  public static Compressor resolveCompressor(String encoding) {
+    Compressor compressor = compressorRegistry.get(encoding);
+    if (compressor == null) {
+      throw new IllegalArgumentException(
+          "Could not resolve compressor for encoding \"" + encoding + "\".");
+    }
+    return compressor;
+  }
+
+  private static Map<String, Compressor> buildCompressorRegistry() {
+    Map<String, Compressor> compressors = new HashMap<>();
+    for (CompressorProvider spi :
+        ServiceLoader.load(CompressorProvider.class, CompressorUtil.class.getClassLoader())) {
+      Compressor compressor = spi.getInstance();
+      compressors.put(compressor.getEncoding(), compressor);
+    }
+    // Hardcode gzip compressor
+    compressors.put(GzipCompressor.getInstance().getEncoding(), GzipCompressor.getInstance());
+    return compressors;
+  }
+}

exporters/common/src/main/java/io/opentelemetry/exporter/internal/compression/GzipCompressor.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.exporter.internal.compression;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.util.zip.GZIPOutputStream;
+
+/**
+ * Gzip {@link Compressor}.
+ *
+ * <p>This class is internal and is hence not for public use. Its APIs are unstable and can change
+ * at any time.
+ */
+public final class GzipCompressor implements Compressor {
+
+  private static final GzipCompressor INSTANCE = new GzipCompressor();
+
+  private GzipCompressor() {}
+
+  public static GzipCompressor getInstance() {
+    return INSTANCE;
+  }
+
+  @Override
+  public String getEncoding() {
+    return "gzip";
+  }
+
+  @Override
+  public OutputStream compress(OutputStream outputStream) throws IOException {
+    return new GZIPOutputStream(outputStream);
+  }
+}

exporters/common/src/main/java/io/opentelemetry/exporter/internal/http/HttpExporterBuilder.java

@@ -11,6 +11,7 @@
 import io.opentelemetry.exporter.internal.ExporterBuilderUtil;
 import io.opentelemetry.exporter.internal.TlsConfigHelper;
 import io.opentelemetry.exporter.internal.auth.Authenticator;
+import io.opentelemetry.exporter.internal.compression.Compressor;
 import io.opentelemetry.exporter.internal.marshal.Marshaler;
 import io.opentelemetry.sdk.common.export.RetryPolicy;
 import java.net.URI;
@@ -19,6 +20,7 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 import java.util.ServiceLoader;
 import java.util.StringJoiner;
 import java.util.concurrent.TimeUnit;
@@ -48,8 +50,8 @@ public final class HttpExporterBuilder<T extends Marshaler> {
   private String endpoint;
 
   private long timeoutNanos = TimeUnit.SECONDS.toNanos(DEFAULT_TIMEOUT_SECS);
+  @Nullable private Compressor compressor;
   private long connectTimeoutNanos = TimeUnit.SECONDS.toNanos(DEFAULT_CONNECT_TIMEOUT_SECS);
-  private boolean compressionEnabled = false;
   private boolean exportAsJson = false;
   private final Map<String, String> constantHeaders = new HashMap<>();
   private Supplier<Map<String, String>> headerSupplier = Collections::emptyMap;
@@ -82,8 +84,8 @@ public HttpExporterBuilder<T> setEndpoint(String endpoint) {
     return this;
   }
 
-  public HttpExporterBuilder<T> setCompression(String compressionMethod) {
-    this.compressionEnabled = compressionMethod.equals("gzip");
+  public HttpExporterBuilder<T> setCompression(@Nullable Compressor compressor) {
+    this.compressor = compressor;
     return this;
   }
 
@@ -141,7 +143,7 @@ public HttpExporterBuilder<T> copy() {
     copy.timeoutNanos = timeoutNanos;
     copy.connectTimeoutNanos = connectTimeoutNanos;
     copy.exportAsJson = exportAsJson;
-    copy.compressionEnabled = compressionEnabled;
+    copy.compressor = compressor;
     copy.constantHeaders.putAll(constantHeaders);
     copy.headerSupplier = headerSupplier;
     copy.tlsConfigHelper = tlsConfigHelper.copy();
@@ -179,7 +181,7 @@ public HttpExporter<T> build() {
     HttpSender httpSender =
         httpSenderProvider.createSender(
             endpoint,
-            compressionEnabled,
+            compressor,
             exportAsJson ? "application/json" : "application/x-protobuf",
             timeoutNanos,
             connectTimeoutNanos,
@@ -202,8 +204,10 @@ public String toString(boolean includePrefixAndSuffix) {
     joiner.add("type=" + type);
     joiner.add("endpoint=" + endpoint);
     joiner.add("timeoutNanos=" + timeoutNanos);
+    joiner.add(
+        "compressorEncoding="
+            + Optional.ofNullable(compressor).map(Compressor::getEncoding).orElse(null));
     joiner.add("connectTimeoutNanos=" + connectTimeoutNanos);
-    joiner.add("compressionEnabled=" + compressionEnabled);
     joiner.add("exportAsJson=" + exportAsJson);
     StringJoiner headersJoiner = new StringJoiner(", ", "Headers{", "}");
     constantHeaders.forEach((key, value) -> headersJoiner.add(key + "=OBFUSCATED"));

exporters/common/src/main/java/io/opentelemetry/exporter/internal/http/HttpSenderProvider.java

@@ -6,6 +6,7 @@
 package io.opentelemetry.exporter.internal.http;
 
 import io.opentelemetry.exporter.internal.auth.Authenticator;
+import io.opentelemetry.exporter.internal.compression.Compressor;
 import io.opentelemetry.sdk.common.export.RetryPolicy;
 import java.util.List;
 import java.util.Map;
@@ -27,7 +28,7 @@ public interface HttpSenderProvider {
   @SuppressWarnings("TooManyParameters")
   HttpSender createSender(
       String endpoint,
-      boolean compressionEnabled,
+      @Nullable Compressor compressor,
       String contentType,
       long timeoutNanos,
       long connectTimeout,

exporters/otlp/all/src/main/java/io/opentelemetry/exporter/otlp/http/logs/OtlpHttpLogRecordExporterBuilder.java

@@ -7,15 +7,18 @@
 
 import static io.opentelemetry.api.internal.Utils.checkArgument;
 import static java.util.Objects.requireNonNull;
+import static java.util.stream.Collectors.joining;
 
 import io.opentelemetry.api.GlobalOpenTelemetry;
 import io.opentelemetry.api.metrics.MeterProvider;
+import io.opentelemetry.exporter.internal.compression.CompressorUtil;
 import io.opentelemetry.exporter.internal.http.HttpExporterBuilder;
 import io.opentelemetry.exporter.internal.otlp.logs.LogsRequestMarshaler;
 import io.opentelemetry.exporter.otlp.internal.OtlpUserAgent;
 import io.opentelemetry.sdk.common.export.RetryPolicy;
 import java.time.Duration;
 import java.util.Map;
+import java.util.Set;
 import java.util.concurrent.TimeUnit;
 import java.util.function.Supplier;
 import javax.net.ssl.SSLContext;
@@ -101,10 +104,16 @@ public OtlpHttpLogRecordExporterBuilder setEndpoint(String endpoint) {
    */
   public OtlpHttpLogRecordExporterBuilder setCompression(String compressionMethod) {
     requireNonNull(compressionMethod, "compressionMethod");
+    if (compressionMethod.equals("none")) {
+      delegate.setCompression(null);
+      return this;
+    }
+    Set<String> supportedCompressionMethods = CompressorUtil.supportedCompressors();
     checkArgument(
-        compressionMethod.equals("gzip") || compressionMethod.equals("none"),
-        "Unsupported compression method. Supported compression methods include: gzip, none.");
-    delegate.setCompression(compressionMethod);
+        supportedCompressionMethods.contains(compressionMethod),
+        "Unsupported compressionMethod. Compression method must be \"none\" or one of: "
+            + supportedCompressionMethods.stream().collect(joining(",", "[", "]")));
+    delegate.setCompression(CompressorUtil.resolveCompressor(compressionMethod));
     return this;
   }
 

exporters/otlp/all/src/main/java/io/opentelemetry/exporter/otlp/http/metrics/OtlpHttpMetricExporterBuilder.java

@@ -7,8 +7,10 @@
 
 import static io.opentelemetry.api.internal.Utils.checkArgument;
 import static java.util.Objects.requireNonNull;
+import static java.util.stream.Collectors.joining;
 
 import io.opentelemetry.api.metrics.MeterProvider;
+import io.opentelemetry.exporter.internal.compression.CompressorUtil;
 import io.opentelemetry.exporter.internal.http.HttpExporterBuilder;
 import io.opentelemetry.exporter.internal.otlp.metrics.MetricsRequestMarshaler;
 import io.opentelemetry.exporter.otlp.internal.OtlpUserAgent;
@@ -19,6 +21,7 @@
 import io.opentelemetry.sdk.metrics.export.MetricExporter;
 import java.time.Duration;
 import java.util.Map;
+import java.util.Set;
 import java.util.concurrent.TimeUnit;
 import java.util.function.Supplier;
 import javax.net.ssl.SSLContext;
@@ -113,10 +116,16 @@ public OtlpHttpMetricExporterBuilder setEndpoint(String endpoint) {
    */
   public OtlpHttpMetricExporterBuilder setCompression(String compressionMethod) {
     requireNonNull(compressionMethod, "compressionMethod");
+    if (compressionMethod.equals("none")) {
+      delegate.setCompression(null);
+      return this;
+    }
+    Set<String> supportedCompressionMethods = CompressorUtil.supportedCompressors();
     checkArgument(
-        compressionMethod.equals("gzip") || compressionMethod.equals("none"),
-        "Unsupported compression method. Supported compression methods include: gzip, none.");
-    delegate.setCompression(compressionMethod);
+        supportedCompressionMethods.contains(compressionMethod),
+        "Unsupported compressionMethod. Compression method must be \"none\" or one of: "
+            + supportedCompressionMethods.stream().collect(joining(",", "[", "]")));
+    delegate.setCompression(CompressorUtil.resolveCompressor(compressionMethod));
     return this;
   }
 

exporters/otlp/all/src/main/java/io/opentelemetry/exporter/otlp/http/trace/OtlpHttpSpanExporterBuilder.java

@@ -7,15 +7,18 @@
 
 import static io.opentelemetry.api.internal.Utils.checkArgument;
 import static java.util.Objects.requireNonNull;
+import static java.util.stream.Collectors.joining;
 
 import io.opentelemetry.api.GlobalOpenTelemetry;
 import io.opentelemetry.api.metrics.MeterProvider;
+import io.opentelemetry.exporter.internal.compression.CompressorUtil;
 import io.opentelemetry.exporter.internal.http.HttpExporterBuilder;
 import io.opentelemetry.exporter.internal.otlp.traces.TraceRequestMarshaler;
 import io.opentelemetry.exporter.otlp.internal.OtlpUserAgent;
 import io.opentelemetry.sdk.common.export.RetryPolicy;
 import java.time.Duration;
 import java.util.Map;
+import java.util.Set;
 import java.util.concurrent.TimeUnit;
 import java.util.function.Supplier;
 import javax.net.ssl.SSLContext;
@@ -101,10 +104,16 @@ public OtlpHttpSpanExporterBuilder setEndpoint(String endpoint) {
    */
   public OtlpHttpSpanExporterBuilder setCompression(String compressionMethod) {
     requireNonNull(compressionMethod, "compressionMethod");
+    if (compressionMethod.equals("none")) {
+      delegate.setCompression(null);
+      return this;
+    }
+    Set<String> supportedCompressionMethods = CompressorUtil.supportedCompressors();
     checkArgument(
-        compressionMethod.equals("gzip") || compressionMethod.equals("none"),
-        "Unsupported compression method. Supported compression methods include: gzip, none.");
-    delegate.setCompression(compressionMethod);
+        supportedCompressionMethods.contains(compressionMethod),
+        "Unsupported compressionMethod. Compression method must be \"none\" or one of: "
+            + supportedCompressionMethods.stream().collect(joining(",", "[", "]")));
+    delegate.setCompression(CompressorUtil.resolveCompressor(compressionMethod));
     return this;
   }