feat: add hdfs support in python

.github/workflows/python_build.yml

@@ -50,21 +50,28 @@ jobs:
           toolchain: stable
           override: true
           components: rustfmt, clippy
+
+      - uses: actions/setup-java@v3
+        with:
+          distribution: 'zulu'
+          java-version: '17'
 
       - uses: Swatinem/rust-cache@v2
 
       - name: Enable manylinux Python targets
         run: |
           echo "/opt/python/cp37-cp37m/bin" >> $GITHUB_PATH
 
+      # hdfs support requires clang 3.5+, which requires an scl package on this image
       - name: Build and install deltalake
         run: |
+          yum install -y llvm-toolset-7
           pip install virtualenv
           virtualenv venv
           source venv/bin/activate
           make setup
           # Install minimum PyArrow version
-          pip install -e .[pandas,devel] pyarrow==7.0.0
+          scl enable llvm-toolset-7 'pip install -e .[pandas,devel] pyarrow==7.0.0'
 
       - name: Run tests
         run: |
@@ -88,6 +95,10 @@ jobs:
           override: true
           components: rustfmt, clippy
 
+      - uses: beyondstorage/setup-hdfs@master
+        with:
+          hdfs-version: '3.3.2'
+
       - uses: Swatinem/rust-cache@v2
 
       - uses: actions/setup-python@v3
@@ -110,7 +121,7 @@ jobs:
       - name: Run tests
         run: |
           source venv/bin/activate
-          python -m pytest -m '((s3 or azure) and integration) or not integration'
+          python -m pytest -m '((s3 or azure or hdfs) and integration) or not integration'
 
       - name: Test without pandas
         run: |

dev/hdfs/core-site.xml

@@ -0,0 +1,10 @@
+<configuration>
+    <property>
+        <name>fs.defaultFS</name>
+        <value>hdfs://localhost:9000</value>
+    </property>
+    <property>
+        <name>fs.permissions.umask-mode</name>
+        <value>000</value>
+    </property>
+</configuration>

dev/hdfs/hdfs-site.xml

@@ -0,0 +1,10 @@
+<configuration>
+    <property>
+        <name>dfs.replication</name>
+        <value>1</value>
+    </property>
+    <property>
+        <name>dfs.namenode.rpc-bind-host</name>
+        <value>0.0.0.0</value>
+    </property>
+</configuration>

dev/hdfs/start-hdfs.sh

@@ -0,0 +1,10 @@
+#!/bin/bash
+
+[ ! -d "/tmp/hadoop-hadoop/dfs/name" ] && hdfs namenode -format
+
+hdfs --daemon start namenode
+hdfs --daemon start datanode
+
+hdfs dfs -chmod 777 /
+
+exec tail -n 1000 -f /var/log/hadoop/*

docker-compose.yml

@@ -27,3 +27,17 @@ services:
     image: mcr.microsoft.com/azure-storage/azurite
     ports:
       - 10000:10000
+
+  hdfs:
+    image: apache/hadoop:3
+    ports:
+      - 9000:9000
+      - 9866:9866
+    volumes:
+      - ./dev/hdfs/core-site.xml:/opt/hadoop/etc/hadoop/core-site.xml
+      - ./dev/hdfs/hdfs-site.xml:/opt/hadoop/etc/hadoop/hdfs-site.xml
+      - ./dev/hdfs/start-hdfs.sh:/start-hdfs.sh
+    entrypoint: /start-hdfs.sh
+    # Only run on a profile so we can use the github action for HDFS support during CI
+    profiles:
+      - hdfs

python/Cargo.toml

@@ -39,7 +39,7 @@ features = ["extension-module", "abi3", "abi3-py37"]
 [dependencies.deltalake]
 path = "../rust"
 version = "0"
-features = ["azure", "gcs", "python", "datafusion", "unity-experimental"]
+features = ["azure", "gcs", "python", "datafusion", "unity-experimental", "hdfs"]
 
 [features]
 default = ["rustls"]

python/pyproject.toml

@@ -98,6 +98,7 @@ markers = [
     "integration: marks tests as integration tests (deselect with '-m \"not integration\"')",
     "s3: marks tests as integration tests with S3 (deselect with '-m \"not s3\"')",
     "azure: marks tests as integration tests with Azure Blob Store",
+    "hdfs: marks tests as integrations tests with HDFS",
     "pandas: marks tests that require pandas",
     "pyspark: marks tests that require pyspark",
 ]

python/tests/conftest.py

@@ -230,3 +230,47 @@ def existing_table(tmp_path: pathlib.Path, sample_data: pa.Table):
     path = str(tmp_path)
     write_deltalake(path, sample_data)
     return DeltaTable(path)
+
+
+@pytest.fixture()
+def hdfs_url(monkeypatch):
+    url = "hdfs://localhost:9000"
+
+    setup_commands = [
+        [
+            "hdfs",
+            "dfs",
+            "-mkdir",
+            f"{url}/deltars",
+        ],
+        [
+            "hdfs",
+            "dfs",
+            "-copyFromLocal",
+            "../rust/tests/data/simple_table",
+            f"{url}/deltars/simple",
+        ],
+    ]
+
+    try:
+        classpath = subprocess.run(["hadoop", "classpath"], capture_output=True).stdout
+        monkeypatch.setenv("CLASSPATH", classpath)
+        for args in setup_commands:
+            subprocess.run(args)
+    except OSError:
+        pytest.skip("hdfs cli not installed")
+
+    yield url
+
+    shutdown_commands = [
+        [
+            "hdfs",
+            "dfs",
+            "-rm",
+            "-r",
+            f"{url}/deltars",
+        ],
+    ]
+
+    for args in shutdown_commands:
+        subprocess.run(args)

python/tests/test_fs.py

@@ -254,3 +254,20 @@ def test_pickle_roundtrip(tmp_path):
 
     infos = store_pkl.get_file_info(["asd.pkl"])
     assert infos[0].size > 0
+
+
+@pytest.mark.hdfs
+@pytest.mark.integration
+@pytest.mark.timeout(timeout=30, method="thread")
+def test_read_hdfs(hdfs_url):
+    table_path = f"{hdfs_url}/deltars/simple"
+    handler = DeltaStorageHandler(table_path)
+    dt = DeltaTable(table_path)
+    files = dt.file_uris()
+    assert len(files) > 0
+    for file in files:
+        rel_path = file[len(table_path) :]
+        with handler.open_input_file(rel_path) as f_:
+            table = pq.read_table(f_)
+            assert isinstance(table, pa.Table)
+            assert table.shape > (0, 0)