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Ingesting Into Data Lake

AWSOfficialPublished by AWS

  • Skill
  • Workflow
  • Data and AI
  • Apache-2.0
  • Low risk

From the author

Import data into the AWS data lake from S3 files, local uploads, JDBC databases (Oracle, SQL Server, PostgreSQL, MySQL, RDS, Aurora), Amazon Redshift, Snowflake, BigQuery, DynamoDB, or existing Glue catalog tables (migration). Default target is S3 Tables; standard Iceberg on a general purpose bucket is supported where S3 Tables is not adopted. Handles one-time loads, recurring pipelines, migrations. Triggers on: import data, load data, ingest, sync database, migrate table, move data to AWS, set up pipeline, ETL, pull from Snowflake, query BigQuery into S3, export DynamoDB, CTAS, convert to Iceberg. Do NOT use for setting up or troubleshooting Glue connections (use connecting-to-data-source), creating empty tables (use creating-data-lake-table), running queries (use querying-data-lake), finding tables by fuzzy name (use finding-data-lake-assets), catalog audit (use exploring-data-catalog), or SaaS platforms like Salesforce, ServiceNow, SAP, MongoDB, Kafka.
— the description by AWS

AutoGineer summary

Written by AutoGineer from the skill’s own files, not by the author

This skill provides a structured workflow for importing data from various sources—including JDBC databases, cloud warehouses like Snowflake and BigQuery, DynamoDB, and S3 files—into an AWS data lake. It prioritizes modern S3 Tables or standard Iceberg formats, ensuring data is queryable and well-structured. The skill guides users through connection verification, target configuration, and validation, while delegating complex setup tasks to specialized sub-skills.

What it does

  • Imports data from JDBC databases, cloud warehouses, and S3 into a data lake
  • Supports one-time loads, recurring ETL pipelines, and catalog migrations
  • Configures target tables using S3 Tables or standard Iceberg formats
  • Validates data integrity via row counts, null checks, and sample verification
  • Automates scheduling for recurring ingestion tasks using Glue triggers
  • Provides clear delegation paths for connection setup and table creation

When to use it

  • When you need to move data from an external database or cloud service into your AWS data lake
  • When setting up a new recurring ETL pipeline for data synchronization
  • When migrating existing Hive-style tables to modern Iceberg formats
  • When you need to perform a one-time bulk load of files from S3 or local storage

Advantages

  • Standardizes ingestion patterns across multiple source types
  • Ensures data quality through built-in validation steps
  • Promotes modern data lake practices by defaulting to S3 Tables and Iceberg
  • Reduces configuration errors by enforcing connection verification before execution

Usage examples

“Import the customers table from our Oracle database into the data lake.”
The agent verifies the existing JDBC connection, confirms the target S3 Tables configuration, and initiates a Glue ETL job to migrate the data.
“Set up a recurring pipeline to pull data from BigQuery into S3.”
The agent configures a Glue job with the necessary BigQuery connection, sets up the target Iceberg table, and creates a Glue trigger for scheduled execution.
“Convert our existing Hive tables to Iceberg.”
The agent performs a catalog migration, updating the table metadata to Iceberg format while maintaining data accessibility.
“Load these local CSV files into the data lake.”
The agent guides the user through the local upload process and maps the data into a queryable S3 Tables format.

Install

  1. Download the skill as a ZIP:

    https://autogineer.com/agent-skills/aws/ingesting-into-data-lake/download
  2. Unzip it into the cross-client skills folder of your project:

    mkdir -p .agents/skills && unzip ingesting-into-data-lake.zip -d .agents/skills

Documentation by AWS

Ingest into Data Lake

Move data from a source into a queryable table in the data lake. This skill assumes the source connection (if one is needed) already exists. For Glue connection setup or troubleshooting, delegate to connecting-to-data-source.

Philosophy

Default to S3 Tables unless the environment says otherwise. S3 Tables is the recommended target for new data lake work. If the user's catalog inventory shows they haven't adopted S3 Tables, recommend standard Iceberg on their existing general-purpose bucket instead of forcing them to change posture.

Common Tasks

You MUST execute commands using AWS MCP server tools when connected -- they provide validation, sandboxed execution, and audit logging. Fall back to AWS CLI only if MCP is unavailable. You MUST explain each step before executing.

Workflow

1. Verify Dependencies and Context
  • You MUST check whether AWS MCP tools or AWS CLI are available and inform the user if missing

  • You MUST confirm target AWS region and verify credentials with aws sts get-caller-identity

  • For SageMaker Unified Studio project roles, note that target tables and connections may be scoped to the project. See the caller ARN detection pattern in querying-data-lake.

2. Classify the Source
User says...Source typeReference
"upload my file", "local CSV", "move to S3"Local filelocal-upload.md
"load from S3", "import CSV/JSON/Parquet from s3://"S3 filess3-files.md
"import from Oracle/Postgres/MySQL/SQL Server/Redshift/RDS/Aurora"JDBCjdbc-ingest.md
"pull from Snowflake", "Snowflake table to S3"Snowflakesnowflake-ingest.md
"import from BigQuery", "GCP analytics to S3"BigQuerybigquery-ingest.md
"export DynamoDB", "DynamoDB to data lake"DynamoDBdynamodb-ingest.md
"migrate Glue table", "convert Hive to Iceberg"Catalog migrationcatalog-migration.md

If the user names Salesforce, ServiceNow, SAP, MongoDB, Kafka, or another SaaS/streaming source, decline -- these are not supported in this release.

If the source table is referenced by a fuzzy or business name ("migrate our orders table", "pull from the sales warehouse"), delegate to finding-data-lake-assets to resolve before proceeding.

3. Confirm Connection Exists (if applicable)

For JDBC, Snowflake, and BigQuery sources, a Glue connection is required. Check:

aws glue get-connection --name <CONNECTION_NAME> --region <REGION>

If the connection does not exist, stop and delegate to connecting-to-data-source to create and test it. Do not proceed with ingest until the connection is verified.

Local files, S3 files, DynamoDB, and catalog migration do not need a Glue connection.

4. Clarify the Target

You MUST ask the user (or suggest based on catalog inventory) before creating or writing to any table:

  • Database/namespace: Does a specific target database exist? Or should one be created?

  • Table: Existing table (append/merge) or new table (delegate to creating-data-lake-table)?

  • Format: S3 Tables (default), standard Iceberg, or raw Parquet?

Inventory-aware defaults:

If you have already run exploring-data-catalog or can quickly check, use what exists:

  • Account has an s3tablescatalog federated catalog and active table buckets: recommend S3 Tables

  • Account has general-purpose buckets with Iceberg tables and no S3 Tables usage: recommend standard Iceberg on their existing bucket

  • Account uses Parquet/ORC on S3 without Iceberg metadata: ask whether to adopt Iceberg now (recommend yes) or continue with raw files

Do not force S3 Tables on customers who haven't adopted it. See iceberg-catalog-config-and-usage.md.

Delegations from this step:

  • Target table doesn't exist -> creating-data-lake-table

  • Target database named by fuzzy term -> finding-data-lake-assets

  • User doesn't know what exists -> exploring-data-catalog

5. Execute Source Workflow

Read the source-specific reference and follow its phases. Each is self-contained with job templates, gotchas, and troubleshooting:

  • Local / S3 / JDBC / Snowflake / BigQuery / DynamoDB / catalog migration -- one reference per source

Common Glue 5.1 or higher job configuration and PySpark templates are shared in glue-job-config.md and glue-job-scripts.md.

6. Validate

Run all three, do not skip:

  1. Row count matches expected (source vs target)

  2. Null check on critical columns

  3. Spot-check 3-5 sample rows

See data-quality-validation.md.

7. Schedule (if recurring)

For recurring pipelines, create a Glue Trigger with a cron schedule. See testing-and-scheduling.md. Simple single-step pipelines use Glue Triggers; multi-step with branching uses MWAA.

Argument Routing

  • S3 path only: Infer one-time load, start Step 2 with S3 files

  • Connection name: Start Step 3 with the named connection

  • Table name: Start Step 4, ask whether this is source or target

  • --target flag: Pre-fill the target format in Step 4

  • No args: Walk through interactively

Gotchas

  • S3 Tables requires Glue 5.1 or higher and --datalake-formats iceberg job argument

  • All spark.sql.catalog.* config MUST go in --conf job arguments, never in spark.conf.set(). Glue 5.x throws AnalysisException: Cannot modify the value of a static config otherwise. See iceberg-catalog-config-and-usage.md for correct catalog configs.

  • The warehouse parameter is required in S3 Tables catalog config. Without it Spark fails with "Cannot derive default warehouse location".

  • Table and column names in S3 Tables MUST be all lowercase

  • overwritePartitions() only replaces partitions present in the DataFrame -- for full refresh with deletes, use createOrReplace()

  • Standard Iceberg targets MUST include a LOCATION clause; S3 Tables MUST NOT

  • DynamoDB does not need a Glue connection -- do not attempt to create one

  • Connection failures during ingest delegate back to connecting-to-data-source; do not debug network/credentials in this skill

  • For target tables in SageMaker Unified Studio projects, ensure the project role has write access to the target namespace before the Glue job runs

Troubleshooting

ErrorLikely causeAction
Access Denied on S3Missing IAM permissionsCheck Glue role has s3:GetObject, s3:PutObject
Access Denied on S3 TablesMissing s3tables:* permissionsAdd S3 Tables inline policy to Glue role
CTAS timeoutDataset too large for AthenaSwitch to Glue ETL or batch with WHERE filters
JDBC connection timeout/auth failureConnection-level issueDelegate to connecting-to-data-source
Throughput exceeded (DynamoDB)Read percent too highLower read.percent or use native export

See error-handling.md for the full catalog.

References

Source-specific
Cross-cutting
Migration-specific
JDBC-specific

Files

references/data-quality-validation.md

Data Quality and Validation

Complete guide for validating data quality during and after import into S3 Tables.

Overview

Data quality validation ensures that loaded data meets expected standards for completeness, accuracy, and consistency. This reference covers:

  • Glue Data Quality rules integration

  • Basic post-load validation queries

  • Common validation patterns

  • Troubleshooting quality issues

Glue Data Quality Rules

Integrate Glue Data Quality rules directly into your ETL jobs for automated validation during the load.

Basic Integration

Add to your Glue job PySpark script:

from awsglue.data_quality import DataQualityEvaluationOptions, DataQualityEvaluator
from awsglue.dynamicframe import DynamicFrame

# Define data quality rules
rules = """
    Rules = [
        RowCount > 0,
        ColumnCount == <expected_count>,
        ColumnValues "<column_name>" Completeness > 0.95,
        ColumnValues "<numeric_column>" between <min> and <max>,
        IsPrimaryKey "<id_column>",
        Uniqueness "<id_column>" > 0.99
    ]
"""

# Evaluate data quality
evaluator = DataQualityEvaluator(
    glueContext,
    rules,
    DynamicFrame.fromDF(transformed_df, glueContext, "check")
)
result = evaluator.evaluate()

# Fail job if quality checks don't pass
if result.overallResult != "PASS":
    raise Exception(f"Data quality check failed: {result}")
Available Data Quality Rules
Rule TypeExampleDescription
RowCountRowCount > 1000Minimum or maximum row count
ColumnCountColumnCount == 10Expected number of columns
CompletenessColumnValues "email" Completeness > 0.95Non-null percentage
UniquenessUniqueness "user_id" > 0.99Unique value percentage
IsPrimaryKeyIsPrimaryKey "order_id"Column has unique non-null values
IsCompleteIsComplete "required_field"Column has no nulls
ColumnValuesColumnValues "age" between 0 and 120Value range checks
DistinctValuesCountDistinctValuesCount "status" in [3,5]Number of unique values
MeanMean "price" between 10.0 and 100.0Average value range
StandardDeviationStandardDeviation "amount" < 50.0Variability check
Complete Example with Multiple Rules
from awsglue.data_quality import DataQualityEvaluationOptions, DataQualityEvaluator
from awsglue.dynamicframe import DynamicFrame

# Define comprehensive data quality rules
rules = """
    Rules = [
        # Basic structure checks
        RowCount > 100,
        ColumnCount == 8,

        # Completeness checks
        IsComplete "customer_id",
        IsComplete "order_date",
        ColumnValues "email" Completeness > 0.90,

        # Uniqueness checks
        IsPrimaryKey "order_id",
        Uniqueness "customer_id" > 0.80,

        # Value range checks
        ColumnValues "quantity" between 1 and 1000,
        ColumnValues "price" between 0.01 and 10000.00,
        ColumnValues "order_date" >= "2023-01-01",

        # Statistical checks
        Mean "price" between 10.0 and 500.0,
        StandardDeviation "quantity" < 100.0,

        # Categorical checks
        ColumnValues "status" in ["pending", "completed", "cancelled"],
        DistinctValuesCount "status" == 3
    ]
"""

# Convert DataFrame to DynamicFrame for evaluation
dynamic_frame = DynamicFrame.fromDF(transformed_df, glueContext, "quality_check")

# Create evaluation options
eval_options = DataQualityEvaluationOptions(
    publishCloudWatchMetrics=True,
    publishResultsToCloudWatch=True
)

# Evaluate data quality
evaluator = DataQualityEvaluator(glueContext, rules, dynamic_frame, eval_options)
result = evaluator.evaluate()

# Check results
if result.overallResult != "PASS":
    # Log failed rules
    for rule_result in result.ruleResults:
        if rule_result.result == "FAIL":
            print(f"Failed rule: {rule_result.rule}")
            print(f"Failure reason: {rule_result.failureReason}")

    # Fail the job
    raise Exception(f"Data quality check failed: {result.overallResult}")
else:
    print("All data quality checks passed!")
Conditional Quality Checks

Only fail on critical issues:

# Define critical vs warning rules
critical_rules = """
    Rules = [
        IsPrimaryKey "order_id",
        IsComplete "customer_id",
        RowCount > 0
    ]
"""

warning_rules = """
    Rules = [
        ColumnValues "email" Completeness > 0.90,
        Mean "price" between 10.0 and 500.0
    ]
"""

# Evaluate critical rules (fail on failure)
critical_result = DataQualityEvaluator(glueContext, critical_rules, dynamic_frame).evaluate()
if critical_result.overallResult != "PASS":
    raise Exception(f"Critical data quality check failed")

# Evaluate warning rules (log but don't fail)
warning_result = DataQualityEvaluator(glueContext, warning_rules, dynamic_frame).evaluate()
if warning_result.overallResult != "PASS":
    print(f"Warning: Non-critical data quality issues detected")
    for rule_result in warning_result.ruleResults:
        if rule_result.result == "FAIL":
            print(f"  - {rule_result.rule}: {rule_result.failureReason}")

Basic Validation Without Glue Data Quality

Even without Glue Data Quality, perform basic checks using Athena queries after the load.

1. Row Count Validation

Verify data was loaded:

-- Count rows in target table
SELECT COUNT(*) as row_count
FROM "<catalog>"."<namespace>"."<table>"

Compare with source row count (if available).

2. Null Checks

Verify critical columns aren't mostly null:

-- Check null percentages for critical columns
SELECT
    COUNT(*) as total_rows,
    SUM(CASE WHEN customer_id IS NULL THEN 1 ELSE 0 END) as null_customer_id,
    SUM(CASE WHEN order_date IS NULL THEN 1 ELSE 0 END) as null_order_date,
    SUM(CASE WHEN amount IS NULL THEN 1 ELSE 0 END) as null_amount,
    -- Calculate percentages
    CAST(SUM(CASE WHEN customer_id IS NULL THEN 1 ELSE 0 END) AS DOUBLE) / COUNT(*) * 100 as pct_null_customer_id,
    CAST(SUM(CASE WHEN order_date IS NULL THEN 1 ELSE 0 END) AS DOUBLE) / COUNT(*) * 100 as pct_null_order_date,
    CAST(SUM(CASE WHEN amount IS NULL THEN 1 ELSE 0 END) AS DOUBLE) / COUNT(*) * 100 as pct_null_amount
FROM "<catalog>"."<namespace>"."<table>"
3. Type Validation

Sample check that types converted correctly:

-- Sample data to verify types
SELECT *
FROM "<catalog>"."<namespace>"."<table>"
LIMIT 100

Look for:

  • Dates that look like strings (e.g., "2024-01-15" instead of DATE)

  • Numbers that are actually strings

  • Truncated decimals

  • Unexpected null values

4. Duplicate Detection

Check for unexpected duplicates on key columns:

-- Find duplicate order_ids
SELECT
    order_id,
    COUNT(*) as duplicate_count
FROM "<catalog>"."<namespace>"."<table>"
GROUP BY order_id
HAVING COUNT(*) > 1
ORDER BY duplicate_count DESC
LIMIT 100
5. Value Range Checks

Verify values are within expected ranges:

-- Check value ranges
SELECT
    MIN(order_date) as min_date,
    MAX(order_date) as max_date,
    MIN(amount) as min_amount,
    MAX(amount) as max_amount,
    MIN(quantity) as min_quantity,
    MAX(quantity) as max_quantity
FROM "<catalog>"."<namespace>"."<table>"
6. Categorical Value Checks

Verify categorical columns have expected values:

-- Check distinct values in status column
SELECT
    status,
    COUNT(*) as count
FROM "<catalog>"."<namespace>"."<table>"
GROUP BY status
ORDER BY count DESC

Expected values should match source data categories.

7. Statistical Checks

Get basic statistics:

-- Calculate basic statistics
SELECT
    COUNT(*) as total_rows,
    AVG(amount) as avg_amount,
    STDDEV(amount) as stddev_amount,
    APPROX_PERCENTILE(amount, 0.5) as median_amount,
    APPROX_PERCENTILE(amount, 0.95) as p95_amount
FROM "<catalog>"."<namespace>"."<table>"

Validation Reporting

Present Results to User

After running validation queries, present results clearly:

Data Load Validation Report:
✓ Row count: 1,234,567 rows loaded
✓ Null checks:
  - customer_id: 0% null (expected: 0%)
  - order_date: 0.1% null (acceptable)
  - amount: 2.3% null (within threshold)
✓ Duplicates: No duplicate order_ids found
✓ Value ranges:
  - order_date: 2023-01-01 to 2024-12-31 (expected)
  - amount: $0.01 to $9,999.99 (valid range)
  - quantity: 1 to 500 (valid range)
✓ Categorical values:
  - status: pending (45%), completed (50%), cancelled (5%)
⚠ Warning: email column has 10% null values (target: < 5%)

Overall: PASS with warnings
Handle Failures

When validation fails:

# In Glue job script
if result.overallResult != "PASS":
    failure_summary = []
    for rule_result in result.ruleResults:
        if rule_result.result == "FAIL":
            failure_summary.append(f"  - {rule_result.rule}: {rule_result.failureReason}")

    error_message = "Data quality validation failed:\n" + "\n".join(failure_summary)
    print(error_message)

    # Optionally send notification or write to error table
    # Then fail the job
    raise Exception(error_message)

Common Validation Patterns

Pre-Load Validation

Before loading, validate source data:

# Sample source data
sample_df = spark.read.format("csv").option("header", "true").load(source_path).limit(1000)

# Check structure
print(f"Row count: {sample_df.count()}")
print(f"Column count: {len(sample_df.columns)}")
print(f"Columns: {sample_df.columns}")
print(f"Schema: {sample_df.printSchema()}")

# Check for issues
null_counts = sample_df.select([
    (col(c).isNull().cast("int")).alias(c) for c in sample_df.columns
]).groupBy().sum()

print("Null counts in sample:")
null_counts.show()
Post-Load Reconciliation

Compare source and target row counts:

# Count source rows
source_count = spark.read.format("csv").option("header", "true").load(source_path).count()

# Count target rows
target_count = spark.sql(f"SELECT COUNT(*) FROM {target_table}").collect()[0][0]

# Verify match
if source_count != target_count:
    print(f"Row count mismatch: source={source_count}, target={target_count}")
    raise Exception("Row count mismatch detected")
else:
    print(f"Row count validation passed: {target_count} rows")

Troubleshooting Quality Issues

Issue: High Null Percentage

Symptoms: More nulls than expected in columns Possible causes:

  • Source data quality issues

  • Type conversion failures (strings that can't be parsed as numbers)

  • Column mapping errors

Solutions:

  1. Check source data for null values

  2. Verify type conversions are correct

  3. Add explicit null handling in transformation

Issue: Duplicate Keys

Symptoms: Primary key column has duplicates Possible causes:

  • Source data has duplicates

  • Multiple loads without deduplication

  • Partition keys included in data

Solutions:

  1. Add deduplication logic to Glue job

  2. Use window functions to keep only latest record

  3. Investigate source data quality

Issue: Value Range Violations

Symptoms: Values outside expected ranges Possible causes:

  • Source data contains outliers

  • Type conversion errors

  • Unit mismatches (e.g., dollars vs cents)

Solutions:

  1. Add filtering or capping in transformation

  2. Verify unit conversions

  3. Add validation rules to reject bad data

Best Practices

  1. Start with basic checks: Row count and null checks catch most issues

  2. Add rules incrementally: Begin with critical rules, expand over time

  3. Use sampling for large datasets: Validate sample before full load

  4. Publish metrics to CloudWatch: Enable monitoring and alerting

  5. Document thresholds: Make quality expectations explicit

  6. Handle warnings separately from errors: Not all issues should fail the job

  7. Test quality rules: Ensure rules actually catch bad data

Summary

Data quality validation workflow:

  1. Pre-load validation: Sample and inspect source data

  2. In-load validation: Use Glue Data Quality rules during ETL

  3. Post-load validation: Run Athena queries to verify results

  4. Reconciliation: Compare source and target row counts

  5. Reporting: Present clear validation results to user

With comprehensive validation, you can ensure data loaded into S3 Tables meets quality standards.

Requirements and compatibility

Works with: Claude Code, Claude apps, OpenAI Codex, GitHub Copilot, Cursor, Gemini CLI, Kiro, OpenCode, Goose, Amp, Roo Code, JetBrains Junie, Factory Droid, Devin (ex-Windsurf), Mistral Vibe, OpenHands, Letta

“Works with” means the tool reads the open Agent Skills format; a skill written for one tool may use features others lack.

Needs: Needs an MCP server, Needs a command-line tool

Security

What our scanner noticed· Low risk

  • Instructions that use the network

A static scan is not a guarantee. Skills are third-party content: review a skill before you let an agent use it.

Attribution and licence

Published by
AWS
Publisher
AWS (Official)
Source
aws/agent-toolkit-for-aws · plugins/aws-data-analytics/skills/ingesting-into-data-lake · commit 0a218f8
Licence
Apache License 2.0 (redistribution allowed)
  • LICENSE (added by AutoGineer from LICENSE)
  • NOTICE (added by AutoGineer from NOTICE)
  • ATTRIBUTION.md (written by AutoGineer)
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