[GitHub] [beam] ettirapp commented on a change in pull request #12581: [BEAM-10378] Add Azure Blob Storage Filesystem

[GitBox <gi...@apache.org>]

ettirapp commented on a change in pull request #12581:
URL: https://github.com/apache/beam/pull/12581#discussion_r471714312



##########
File path: sdks/java/io/azure/src/main/java/org/apache/beam/sdk/io/azure/blobstore/AzureBlobStoreFileSystem.java
##########
@@ -17,67 +17,438 @@
  */
 package org.apache.beam.sdk.io.azure.blobstore;
 
+import static java.nio.channels.Channels.newChannel;
+import static org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.Preconditions.checkArgument;
+import static org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.Preconditions.checkNotNull;
+import static org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.Preconditions.checkState;
+
+import com.azure.core.http.rest.PagedIterable;
+import com.azure.storage.blob.BlobClient;
+import com.azure.storage.blob.BlobContainerClient;
+import com.azure.storage.blob.BlobServiceClient;
+import com.azure.storage.blob.BlobServiceClientBuilder;
+import com.azure.storage.blob.models.BlobItem;
+import com.azure.storage.blob.models.BlobProperties;
+import com.azure.storage.blob.models.BlobStorageException;
+import com.azure.storage.blob.models.ListBlobsOptions;
+import com.microsoft.azure.storage.CloudStorageAccount;
+import com.microsoft.azure.storage.SharedAccessAccountPolicy;
+import java.io.FileNotFoundException;
 import java.io.IOException;
+import java.io.OutputStream;
 import java.nio.channels.ReadableByteChannel;
 import java.nio.channels.WritableByteChannel;
+import java.time.Duration;
+import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Date;
+import java.util.Iterator;
 import java.util.List;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
 import org.apache.beam.sdk.io.FileSystem;
+import org.apache.beam.sdk.io.azure.options.BlobstoreClientBuilderFactory;
+import org.apache.beam.sdk.io.azure.options.BlobstoreOptions;
 import org.apache.beam.sdk.io.fs.CreateOptions;
 import org.apache.beam.sdk.io.fs.MatchResult;
+import org.apache.beam.sdk.util.InstanceBuilder;
 import org.apache.beam.vendor.guava.v26_0_jre.com.google.common.annotations.VisibleForTesting;
+import org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.Supplier;
+import org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.Suppliers;
+import org.apache.beam.vendor.guava.v26_0_jre.com.google.common.collect.FluentIterable;
+import org.apache.beam.vendor.guava.v26_0_jre.com.google.common.collect.ImmutableList;
+import org.apache.beam.vendor.guava.v26_0_jre.com.google.common.collect.ImmutableSet;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 class AzureBlobStoreFileSystem extends FileSystem<AzfsResourceId> {
 
+  private static final Logger LOG = LoggerFactory.getLogger(AzureBlobStoreFileSystem.class);
+
+  private static final ImmutableSet<String> NON_READ_SEEK_EFFICIENT_ENCODINGS =
+      ImmutableSet.of("gzip");
+
+  private Supplier<BlobServiceClient> client;
+  private final BlobstoreOptions options;
+
+  AzureBlobStoreFileSystem(BlobstoreOptions options) {
+    this.options = checkNotNull(options, "options");
+
+    BlobServiceClientBuilder builder =
+        InstanceBuilder.ofType(BlobstoreClientBuilderFactory.class)
+            .fromClass(options.getBlobstoreClientFactoryClass())
+            .build()
+            .createBuilder(options);
+
+    // The Supplier is to make sure we don't call .build() unless we are actually using Azure.
+    client = Suppliers.memoize(builder::buildClient);
+  }
+
+  @VisibleForTesting
+  void setClient(BlobServiceClient client) {
+    this.client = Suppliers.ofInstance(client);
+  }
+
+  @VisibleForTesting
+  BlobServiceClient getClient() {
+    return client.get();
+  }
+
   @Override
   protected String getScheme() {
-    return "azfs";
+    return AzfsResourceId.SCHEME;
   }
 
   @Override
-  protected List<MatchResult> match(List<String> specs) throws IOException {
-    // TODO
-    return null;
+  protected List<MatchResult> match(List<String> specs) {
+    List<AzfsResourceId> paths =
+        specs.stream().map(AzfsResourceId::fromUri).collect(Collectors.toList());
+    List<AzfsResourceId> globs = new ArrayList<>();
+    List<AzfsResourceId> nonGlobs = new ArrayList<>();
+    List<Boolean> isGlobBooleans = new ArrayList<>();
+
+    for (AzfsResourceId path : paths) {
+      if (path.isWildcard()) {
+        globs.add(path);
+        isGlobBooleans.add(true);
+      } else {
+        nonGlobs.add(path);
+        isGlobBooleans.add(false);
+      }
+    }
+
+    Iterator<MatchResult> globMatches = matchGlobPaths(globs).iterator();
+    Iterator<MatchResult> nonGlobMatches = matchNonGlobPaths(nonGlobs).iterator();
+
+    ImmutableList.Builder<MatchResult> matchResults = ImmutableList.builder();
+    for (Boolean isGlob : isGlobBooleans) {
+      if (isGlob) {
+        checkState(globMatches.hasNext(), "Expect globMatches has next.");
+        matchResults.add(globMatches.next());
+      } else {
+        checkState(nonGlobMatches.hasNext(), "Expect nonGlobMatches has next.");
+        matchResults.add(nonGlobMatches.next());
+      }
+    }
+    checkState(!globMatches.hasNext(), "Expect no more elements in globMatches.");
+    checkState(!nonGlobMatches.hasNext(), "Expect no more elements in nonGlobMatches.");
+
+    return matchResults.build();
+  }
+
+  /**
+   * Expands glob expressions to regular expressions.
+   *
+   * @param globExp the glob expression to expand
+   * @return a string with the regular expression this glob expands to
+   */
+  @VisibleForTesting
+  static String wildcardToRegexp(String globExp) {
+    StringBuilder dst = new StringBuilder();
+    char[] src = globExp.replace("**/*", "**").toCharArray();
+    int i = 0;
+    while (i < src.length) {
+      char c = src[i++];
+      switch (c) {
+        case '*':
+          // One char lookahead for **
+          if (i < src.length && src[i] == '*') {
+            dst.append(".*");
+            ++i;
+          } else {
+            dst.append("[^/]*");
+          }
+          break;
+        case '?':
+          dst.append("[^/]");
+          break;
+        case '.':
+        case '+':
+        case '{':
+        case '}':
+        case '(':
+        case ')':
+        case '|':
+        case '^':
+        case '$':
+          // These need to be escaped in regular expressions
+          dst.append('\\').append(c);
+          break;
+        case '\\':
+          i = doubleSlashes(dst, src, i);
+          break;
+        default:
+          dst.append(c);
+          break;
+      }
+    }
+    return dst.toString();
+  }
+
+  private static int doubleSlashes(StringBuilder dst, char[] src, int i) {
+    // Emit the next character without special interpretation
+    dst.append("\\\\");
+    if ((i - 1) != src.length) {
+      dst.append(src[i]);
+      i++;
+    } else {
+      // A backslash at the very end is treated like an escaped backslash
+      dst.append('\\');
+    }
+    return i;
+  }
+
+  private List<MatchResult> matchGlobPaths(List<AzfsResourceId> globs) {
+    return FluentIterable.from(globs).transform(this::expand).toList();
+  }
+
+  /** Expands a pattern into {@link MatchResult}. */
+  @VisibleForTesting
+  MatchResult expand(AzfsResourceId azfsPattern) {
+
+    checkArgument(azfsPattern.isWildcard(), "is Wildcard");
+    String blobPrefix = azfsPattern.getBlobNonWildcardPrefix();
+    Pattern wildcardAsRegexp = Pattern.compile(wildcardToRegexp(azfsPattern.getBlob()));
+
+    LOG.debug(
+        "matching files in container {}, prefix {} against pattern {}",
+        azfsPattern.getContainer(),
+        blobPrefix,
+        wildcardAsRegexp.toString());
+
+    ListBlobsOptions listOptions = new ListBlobsOptions().setPrefix(blobPrefix);
+    Duration timeout = Duration.ZERO.plusMinutes(1);
+
+    String account = azfsPattern.getAccount();
+    String container = azfsPattern.getContainer();
+    BlobContainerClient blobContainerClient = client.get().getBlobContainerClient(container);
+    PagedIterable<BlobItem> blobs = blobContainerClient.listBlobs(listOptions, timeout);
+    List<MatchResult.Metadata> results = new ArrayList<>();
+
+    blobs.forEach(
+        blob -> {
+          String name = blob.getName();
+          if (wildcardAsRegexp.matcher(name).matches() && !name.endsWith("/")) {
+            LOG.debug("Matched object: {}", name);
+
+            BlobProperties properties = blobContainerClient.getBlobClient(name).getProperties();
+            AzfsResourceId rid =
+                AzfsResourceId.fromComponents(account, container, name)
+                    .withSize(properties.getBlobSize())
+                    .withLastModified(Date.from(properties.getLastModified().toInstant()));
+
+            results.add(toMetadata(rid, properties.getContentEncoding()));
+          }
+        });
+
+    return MatchResult.create(MatchResult.Status.OK, results);
+  }
+
+  private MatchResult.Metadata toMetadata(AzfsResourceId path, String contentEncoding) {
+
+    checkArgument(path.getSize().isPresent(), "path has size");
+    boolean isReadSeekEfficient = !NON_READ_SEEK_EFFICIENT_ENCODINGS.contains(contentEncoding);
+
+    return MatchResult.Metadata.builder()
+        .setIsReadSeekEfficient(isReadSeekEfficient)
+        .setResourceId(path)
+        .setSizeBytes(path.getSize().get())
+        .setLastModifiedMillis(path.getLastModified().transform(Date::getTime).or(0L))
+        .build();
+  }
+
+  /**
+   * Returns {@link MatchResult MatchResults} for the given {@link AzfsResourceId paths}.
+   *
+   * <p>The number of returned {@link MatchResult MatchResults} equals to the number of given {@link
+   * AzfsResourceId paths}. Each {@link MatchResult} contains one {@link MatchResult.Metadata}.
+   */
+  @VisibleForTesting
+  private Iterable<MatchResult> matchNonGlobPaths(List<AzfsResourceId> paths) {
+    ImmutableList.Builder<MatchResult> toReturn = ImmutableList.builder();
+    for (AzfsResourceId path : paths) {
+      toReturn.add(toMatchResult(path));
+    }
+    return toReturn.build();
+  }
+
+  private MatchResult toMatchResult(AzfsResourceId path) {
+    BlobClient blobClient =
+        client.get().getBlobContainerClient(path.getContainer()).getBlobClient(path.getBlob());
+    BlobProperties blobProperties;
+
+    try {
+      blobProperties = blobClient.getProperties();
+    } catch (BlobStorageException e) {
+      if (e.getStatusCode() == 404) {
+        return MatchResult.create(MatchResult.Status.NOT_FOUND, new FileNotFoundException());
+      }
+      return MatchResult.create(MatchResult.Status.ERROR, new IOException(e));
+    }
+
+    return MatchResult.create(
+        MatchResult.Status.OK,
+        ImmutableList.of(
+            toMetadata(
+                path.withSize(blobProperties.getBlobSize())
+                    .withLastModified(Date.from(blobProperties.getLastModified().toInstant())),
+                blobProperties.getContentEncoding())));
   }
 
   @Override
   protected WritableByteChannel create(AzfsResourceId resourceId, CreateOptions createOptions)
       throws IOException {
-    // TODO
-    return null;
+    BlobContainerClient blobContainerClient =
+        client.get().getBlobContainerClient(resourceId.getContainer());
+    if (!blobContainerClient.exists()) {
+      throw new UnsupportedOperationException("create does not create containers.");

Review comment:
       The operation is unsupported because the user is trying to create a file in a container that doesn't exist, and I made a design decision that the create method does not recursively create containers, it only creates files within containers that already exist.  I can change this to a `FileNotFoundException` stating that the container doesn't exist if that is more intuitive.




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