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@ -7,24 +7,24 @@ This manual guides data engineers & data analysts (DA/DE) through using Airflow,
## Table of Contents
- [Components](#components)
- [Airflow](#airflow)
- [Superset](#superset)
- [Trino](#trino)
- [Object Storage](#object-storage)
- [Airflow](#airflow)
- [Superset](#superset)
- [Trino](#trino)
- [Object Storage](#object-storage)
- [Workflow](#workflow)
- [Data Pipeline](#data-pipeline)
- [1. Data Ingestion](#1-data-ingestion)
- [2. Raw Data Storage](#2-raw-data-storage)
- [3. Data Transformation / ETL](#3-data-transformation--etl)
- [4. Processed Data Storage](#4-processed-data-storage)
- [5. Data Visualization](#5-data-visualization)
- [1. Data Ingestion](#1-data-ingestion)
- [2. Raw Data Storage](#2-raw-data-storage)
- [3. Data Transformation / ETL](#3-data-transformation--etl)
- [4. Processed Data Storage](#4-processed-data-storage)
- [5. Data Visualization](#5-data-visualization)
- [Example](#example)
- [sample_dag.py](#sample_dagpy)
- [Dockerfile](#dockerfile)
- [Build & publish container image](#build--publish-container-image)
- [sample_dat.py](#sample_dagpy)
- [Dockerfile](#dockerfile)
- [Build & publish container image](#build--publish-container-image)
---
## Components
### Airflow
@ -46,33 +46,41 @@ An **S3-compatible storage provider** (e.g., MinIO) used to store and retrieve u
## Workflow
```mermaid
flowchart TB
flowchart TD
subgraph src ["Data source"]
direction LR
ext_api[/"API<br>(HTTP, REST, Graph)"/]
ext_s3@{ shape: cyl, label: "Object Storage<br>(S3, MinIO, GCS)" }
ext_db@{ shape: cyl, label: "Database<br>(MySQL, PostgreSQL)" }
ext_fs@{ shape: cyl, label: "Filesystem<br>(HDFS, NAS)" }
end
%% STAGE 1: DATA SOURCES
A["Data Sources
(S3 / MinIO, DBs, APIs)"] -->|Ingestion Jobs| B[Apache Airflow]
subgraph emgr ["Data Platform"]
dag@{ shape: docs, label: "Python DAG" }
af["Airflow"]
tr["Trino"]
ss("Superset")
end
%% STAGE 2: RAW STORAGE
B -->|Store Raw Data| C["Raw Zone
(S3 / MinIO)"]
s3@{ shape: cyl, label: "S3<br>(MinIO)" }
%% STAGE 3: TRANSFORMATION
C -->|DAG / ETL / SQL Queries| D["Trino
(Query Engine)"]
B -->|Workflow Orchestration| D
dag -- (1a)<br>Fetch<br>raw data<br>(API, SDK) --> src
dag -- (1b) --> tr
tr -- (1b)<br>Fetch<br>raw data<br>(Trino connector) --> src
af -- (2)<br>Execute<br>script --> dag
dag -- (3)<br>Store<br>processed<br>data<br>(SQL) --> tr
s3 <-- (4)<br>Read/write data<br>(Hive / Iceberg format) --> tr
ss -- (5)<br>Query<br>processed<br>data<br>(SQL) --> tr
%% STAGE 4: PROCESSED STORAGE
D -->|Write Processed Data| E["Processed / Curated Zone
(S3 / MinIO)"]
%% STAGE 5: QUERY LAYER
E -->|Query Interface| F["Trino
(SQL Access Layer)"]
%% STAGE 6: VISUALIZATION
F -->|Data Access| G["Apache Superset
(Dashboarding & Analytics)"]
%% LABELS
classDef core fill:#4a90e2,stroke:#2c3e50,stroke-width:1px,color:white;
classDef storage fill:#6dbf4b,stroke:#2c3e50,stroke-width:1px,color:white;
classDef optional fill:#aaaaaa,stroke:#333,stroke-width:0.5px,color:white;
class B,D,F,G core;
class C,E storage;
class H1,H2,H3,H4 optional;
```
## Data Pipeline
@ -82,22 +90,18 @@ ss -- (5)<br>Query<br>processed<br>data<br>(SQL) --> tr
Collect raw data from multiple sources and bring it into the platform in a structured workflow.
Components:
- Apache Airflow (orchestrates ingestion pipelines)
Data sources:
- Object storage (S3 / MinIO)
- files: csv, xlsx, txt etc.
- files: csv, xlsx, txt etc.
- APIs (REST/GraphQL endpoints)
- Databases (PostgreSQL, MySQL, etc.)
DA/DE tasks:
- Create DAGs in Airflow to pull data periodically.
Sample Airflow DAG (Python):
Sample Airflow DAG (Python):
- See [sample_dag.py](#sample_dagpy)
### 2. Raw Data Storage
@ -105,15 +109,12 @@ Sample Airflow DAG (Python):
Store the raw, unprocessed data in a centralized location for auditing and reprocessing.
Components:
- Object storage (S3 / MinIO)
DA/DE tasks:
- Organize data using bucket/folder structures.
Sample S3 Folder Structure:
Sample S3 Folder Structure:
- See [Data source files](#data-source-files)
### 3. Data Transformation / ETL
@ -121,20 +122,16 @@ Sample S3 Folder Structure:
Clean, enrich, and transform raw data into structured, query-ready form.
Components:
- Apache Airflow (orchestration)
- Trino (SQL engine for transformations)
DA/DE tasks:
- Schedule transformation jobs in Airflow DAGs.
Airflow DAG Snippet for ETL:
Airflow DAG Snippet for ETL:
- see [sample_dag.py](#sample_dagpy)
S3 Folder Structure:
S3 Folder Structure:
- see [Python DAG files](#python-dag-files)
### 4. Processed Data Storage
@ -142,12 +139,10 @@ S3 Folder Structure:
Store the transformed and curated datasets in a queryable format for analytics and dashboarding.
Components:
- Trino (query engine / SQL layer)
- S3 (object storage for processed datasets)
DA/DE tasks:
- Partition tables by date, region, or other dimensions for fast queries.
- Grant read access to Superset.
@ -156,20 +151,17 @@ DA/DE tasks:
Provide dashboards and reports to enable insights and business decision-making.
Components:
- Apache Superset (dashboarding / BI tool)
DA/DE tasks:
- Create datasets and charts (bar, line, heatmaps).
- Build dashboards combining multiple metrics.
- Apply filters and access controls for different users.
Data source connections:
- 'Data Platform' service already configured these database connections in Superset:
- iceberg
- hive
- iceberg
- hive
## Example
@ -217,7 +209,7 @@ with DAG(
region_name=os.getenv("S3_REGION"),
)
bucket_name = os.getenv("S3_BUCKET")
bucket_name = 'emgr'
key = 'airflow/excel/computer-parts-sales.xlsx'
sheet_name = 'Sheet1'
columns = ['Date', 'Part', 'Quantity_Sold', 'Unit_Price', 'Total_Sale']
@ -258,7 +250,7 @@ with DAG(
region_name=os.getenv("S3_REGION"),
)
bucket_name = os.getenv("S3_BUCKET")
bucket_name = 'emgr'
key = data.get('key')
# read csv file from s3
@ -310,7 +302,6 @@ with DAG(
```
Image `azwan082/python:3.11-airflow-dag-3` used in example above contains these Python libraries:
- boto3 - to connect to S3-compatible object storage
- pandas - to process data using DataFrame
- requests - to perform HTTP requests to REST API or webpage
@ -324,11 +315,11 @@ If you need more libraries, or want to customize the image, refer to [Dockerfile
Notes:
- XCom means cross-communication, where one task can return values to be consumed by another task:
- Sample code above has two tasks, to demo how XCom works. For simple DAG, one task is enough.
- Do not return large data between task through XCom, the pod may fail to start. Store resulting data in object storage.
- Sample code above has two tasks, to demo how XCom works. For simple DAG, one task is enough.
- Do not return large data between task through XCom, the pod may fail to start. Store resulting data in object storage.
- Since Airflow is configured to use KubernetesExecutor, each tasks in a DAG will be executed on a new pod. In order to reduce impact of pods startup overhead:
- Design your DAGs with fewer tasks.
- Avoid scheduling DAGs too frequently, set at least 5 minutes apart.
- Design your DAGs with fewer tasks.
- Avoid scheduling DAGs too frequently, set at least 5 minutes apart.
### Dockerfile
@ -352,24 +343,18 @@ CMD ["python3"]
- Requirement: Docker installed & Docker hub account
- Build image (run in folder containing the Dockerfile):
```bash
docker build -t <username>/python:3.11-airflow-dag .
```
- Push image to Docker hub:
```bash
docker login
docker push <username>/python:3.11-airflow-dag
```
- Update dag file to use this new image
```python
@task.kubernetes(image="<username>/python:3.11-airflow-dag")
```
- Note: update the image tag everytime you build a new image. E.g `python:3.11-airflow-dag-1.1`
## Object Storage Folder Structure
@ -387,7 +372,6 @@ Assuming the 'Data Platform' service is deployed with 'Object Storage' configura
- **MUST** be stored in `airflow/dags` folder in the target bucket, in order to be automatically synced to Airflow.
- Example object path:
```
s3://s3.example.net/emgr/airflow/dags/sample_dag.py
s3://s3.example.net/emgr/airflow/dags/monthly_sales.py
@ -397,14 +381,13 @@ s3://s3.example.net/emgr/airflow/dags/monthly_sales.py
- Example data source files are xlsx, csv or txt files, for both raw & processed data.
- They can be stored in any location within the target bucket, **EXCEPT** locations from sections above:
- `warehouses`
- `airflow/dags` (specifically)
- `warehouses`
- `airflow/dags` (specifically)
- However, you may, and encouraged, to store the data source files inside the `airflow` folder.
- Example object path:
```
s3://s3.example.net/emgr/airflow/raw/sample.csv
s3://s3.example.net/emgr/airflow/output/voters.csv
s3://s3.example.net/emgr/2025-11-11/data.json
s3://s3.example.net/emgr/raw/db/orders_20251111.csv
```
```