docs: add sample for writing data with Beam (#80)

Co-authored-by: Tres Seaver <tseaver@palladion.com>

samples/beam/hello_world_write.py

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+# Copyright 2020 Google Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import datetime
+
+import apache_beam as beam
+from apache_beam.io.gcp.bigtableio import WriteToBigTable
+from apache_beam.options.pipeline_options import PipelineOptions
+from google.cloud.bigtable import row
+
+
+class BigtableOptions(PipelineOptions):
+    @classmethod
+    def _add_argparse_args(cls, parser):
+        parser.add_argument(
+            '--bigtable-project',
+            help='The Bigtable project ID, this can be different than your '
+                 'Dataflow project',
+            default='bigtable-project')
+        parser.add_argument(
+            '--bigtable-instance',
+            help='The Bigtable instance ID',
+            default='bigtable-instance')
+        parser.add_argument(
+            '--bigtable-table',
+            help='The Bigtable table ID in the instance.',
+            default='bigtable-table')
+
+
+class CreateRowFn(beam.DoFn):
+    def process(self, key):
+        direct_row = row.DirectRow(row_key=key)
+        direct_row.set_cell(
+            "stats_summary",
+            b"os_build",
+            b"android",
+            datetime.datetime.now())
+        return [direct_row]
+
+
+def run(argv=None):
+    """Build and run the pipeline."""
+    options = BigtableOptions(argv)
+    with beam.Pipeline(options=options) as p:
+        p | beam.Create(["phone#4c410523#20190501",
+                         "phone#4c410523#20190502"]) | beam.ParDo(
+            CreateRowFn()) | WriteToBigTable(
+            project_id=options.bigtable_project,
+            instance_id=options.bigtable_instance,
+            table_id=options.bigtable_table)
+
+
+if __name__ == '__main__':
+    run()

samples/beam/hello_world_write_test.py

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+# Copyright 2020 Google Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import os
+import uuid
+
+from google.cloud import bigtable
+import pytest
+
+import hello_world_write
+
+PROJECT = os.environ['GOOGLE_CLOUD_PROJECT']
+BIGTABLE_INSTANCE = os.environ['BIGTABLE_INSTANCE']
+TABLE_ID_PREFIX = 'mobile-time-series-{}'
+
+
+@pytest.fixture(scope="module", autouse=True)
+def table_id():
+    client = bigtable.Client(project=PROJECT, admin=True)
+    instance = client.instance(BIGTABLE_INSTANCE)
+
+    table_id = TABLE_ID_PREFIX.format(str(uuid.uuid4())[:16])
+    table = instance.table(table_id)
+    if table.exists():
+        table.delete()
+
+    table.create(column_families={'stats_summary': None})
+    yield table_id
+
+    table.delete()
+
+
+def test_hello_world_write(table_id):
+    hello_world_write.run([
+        '--bigtable-project=%s' % PROJECT,
+        '--bigtable-instance=%s' % BIGTABLE_INSTANCE,
+        '--bigtable-table=%s' % table_id])
+
+    client = bigtable.Client(project=PROJECT, admin=True)
+    instance = client.instance(BIGTABLE_INSTANCE)
+    table = instance.table(table_id)
+
+    rows = table.read_rows()
+    count = 0
+    for _ in rows:
+        count += 1
+    assert count == 2

samples/beam/noxfile.py

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+# Copyright 2019 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import print_function
+
+import os
+from pathlib import Path
+import sys
+
+import nox
+
+
+# WARNING - WARNING - WARNING - WARNING - WARNING
+# WARNING - WARNING - WARNING - WARNING - WARNING
+#           DO NOT EDIT THIS FILE EVER!
+# WARNING - WARNING - WARNING - WARNING - WARNING
+# WARNING - WARNING - WARNING - WARNING - WARNING
+
+# Copy `noxfile_config.py` to your directory and modify it instead.
+
+
+# `TEST_CONFIG` dict is a configuration hook that allows users to
+# modify the test configurations. The values here should be in sync
+# with `noxfile_config.py`. Users will copy `noxfile_config.py` into
+# their directory and modify it.
+
+TEST_CONFIG = {
+    # You can opt out from the test for specific Python versions.
+    'ignored_versions': ["2.7"],
+
+    # An envvar key for determining the project id to use. Change it
+    # to 'BUILD_SPECIFIC_GCLOUD_PROJECT' if you want to opt in using a
+    # build specific Cloud project. You can also use your own string
+    # to use your own Cloud project.
+    'gcloud_project_env': 'GOOGLE_CLOUD_PROJECT',
+    # 'gcloud_project_env': 'BUILD_SPECIFIC_GCLOUD_PROJECT',
+
+    # A dictionary you want to inject into your test. Don't put any
+    # secrets here. These values will override predefined values.
+    'envs': {},
+}
+
+
+try:
+    # Ensure we can import noxfile_config in the project's directory.
+    sys.path.append('.')
+    from noxfile_config import TEST_CONFIG_OVERRIDE
+except ImportError as e:
+    print("No user noxfile_config found: detail: {}".format(e))
+    TEST_CONFIG_OVERRIDE = {}
+
+# Update the TEST_CONFIG with the user supplied values.
+TEST_CONFIG.update(TEST_CONFIG_OVERRIDE)
+
+
+def get_pytest_env_vars():
+    """Returns a dict for pytest invocation."""
+    ret = {}
+
+    # Override the GCLOUD_PROJECT and the alias.
+    env_key = TEST_CONFIG['gcloud_project_env']
+    # This should error out if not set.
+    ret['GOOGLE_CLOUD_PROJECT'] = os.environ[env_key]
+
+    # Apply user supplied envs.
+    ret.update(TEST_CONFIG['envs'])
+    return ret
+
+
+# DO NOT EDIT - automatically generated.
+# All versions used to tested samples.
+ALL_VERSIONS = ["2.7", "3.6", "3.7", "3.8"]
+
+# Any default versions that should be ignored.
+IGNORED_VERSIONS = TEST_CONFIG['ignored_versions']
+
+TESTED_VERSIONS = sorted([v for v in ALL_VERSIONS if v not in IGNORED_VERSIONS])
+
+INSTALL_LIBRARY_FROM_SOURCE = bool(os.environ.get("INSTALL_LIBRARY_FROM_SOURCE", False))
+#
+# Style Checks
+#
+
+
+def _determine_local_import_names(start_dir):
+    """Determines all import names that should be considered "local".
+
+    This is used when running the linter to insure that import order is
+    properly checked.
+    """
+    file_ext_pairs = [os.path.splitext(path) for path in os.listdir(start_dir)]
+    return [
+        basename
+        for basename, extension in file_ext_pairs
+        if extension == ".py"
+        or os.path.isdir(os.path.join(start_dir, basename))
+        and basename not in ("__pycache__")
+    ]
+
+
+# Linting with flake8.
+#
+# We ignore the following rules:
+#   E203: whitespace before ‘:’
+#   E266: too many leading ‘#’ for block comment
+#   E501: line too long
+#   I202: Additional newline in a section of imports
+#
+# We also need to specify the rules which are ignored by default:
+# ['E226', 'W504', 'E126', 'E123', 'W503', 'E24', 'E704', 'E121']
+FLAKE8_COMMON_ARGS = [
+    "--show-source",
+    "--builtin=gettext",
+    "--max-complexity=20",
+    "--import-order-style=google",
+    "--exclude=.nox,.cache,env,lib,generated_pb2,*_pb2.py,*_pb2_grpc.py",
+    "--ignore=E121,E123,E126,E203,E226,E24,E266,E501,E704,W503,W504,I202",
+    "--max-line-length=88",
+]
+
+
+@nox.session
+def lint(session):
+    session.install("flake8", "flake8-import-order")
+
+    local_names = _determine_local_import_names(".")
+    args = FLAKE8_COMMON_ARGS + [
+        "--application-import-names",
+        ",".join(local_names),
+        "."
+    ]
+    session.run("flake8", *args)
+
+
+#
+# Sample Tests
+#
+
+
+PYTEST_COMMON_ARGS = ["--junitxml=sponge_log.xml"]
+
+
+def _session_tests(session, post_install=None):
+    """Runs py.test for a particular project."""
+    if os.path.exists("requirements.txt"):
+        session.install("-r", "requirements.txt")
+
+    if os.path.exists("requirements-test.txt"):
+        session.install("-r", "requirements-test.txt")
+
+    if INSTALL_LIBRARY_FROM_SOURCE:
+        session.install("-e", _get_repo_root())
+
+    if post_install:
+        post_install(session)
+
+    session.run(
+        "pytest",
+        *(PYTEST_COMMON_ARGS + session.posargs),
+        # Pytest will return 5 when no tests are collected. This can happen
+        # on travis where slow and flaky tests are excluded.
+        # See http://doc.pytest.org/en/latest/_modules/_pytest/main.html
+        success_codes=[0, 5],
+        env=get_pytest_env_vars()
+    )
+
+
+@nox.session(python=ALL_VERSIONS)
+def py(session):
+    """Runs py.test for a sample using the specified version of Python."""
+    if session.python in TESTED_VERSIONS:
+        _session_tests(session)
+    else:
+        session.skip("SKIPPED: {} tests are disabled for this sample.".format(
+            session.python
+        ))
+
+
+#
+# Readmegen
+#
+
+
+def _get_repo_root():
+    """ Returns the root folder of the project. """
+    # Get root of this repository. Assume we don't have directories nested deeper than 10 items.
+    p = Path(os.getcwd())
+    for i in range(10):
+        if p is None:
+            break
+        if Path(p / ".git").exists():
+            return str(p)
+        p = p.parent
+    raise Exception("Unable to detect repository root.")
+
+
+GENERATED_READMES = sorted([x for x in Path(".").rglob("*.rst.in")])
+
+
+@nox.session
+@nox.parametrize("path", GENERATED_READMES)
+def readmegen(session, path):
+    """(Re-)generates the readme for a sample."""
+    session.install("jinja2", "pyyaml")
+    dir_ = os.path.dirname(path)
+
+    if os.path.exists(os.path.join(dir_, "requirements.txt")):
+        session.install("-r", os.path.join(dir_, "requirements.txt"))
+
+    in_file = os.path.join(dir_, "README.rst.in")
+    session.run(
+        "python", _get_repo_root() + "/scripts/readme-gen/readme_gen.py", in_file
+    )

samples/beam/requirements-test.txt

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+pytest==6.0.1

samples/beam/requirements.txt

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+apache-beam==2.23.0
+google-cloud-bigtable==1.4.0
+google-cloud-core==1.3.0