Blazer

Explore your data with SQL. Easily create charts and dashboards, and share them with your team.

Try it out

Blazer is also available as a Docker image.

🍊 Battle-tested at Instacart

Features

Multiple data sources - PostgreSQL, MySQL, Redshift, and many more
Variables - run the same queries with different values
Checks & alerts - get emailed when bad data appears
Audits - all queries are tracked
Security - works with your authentication system

Installation

Add this line to your application’s Gemfile:

gem "blazer"

Run:

rails generate blazer:install
rails db:migrate

And mount the dashboard in your config/routes.rb:

mount Blazer::Engine, at: "blazer"

For production, specify your database:

ENV["BLAZER_DATABASE_URL"] = "postgres://user:password@hostname:5432/database"

When possible, Blazer tries to protect against queries which modify data by running each query in a transaction and rolling it back, but a safer approach is to use a read-only user. See how to create one.

Checks (optional)

Be sure to set a host in config/environments/production.rb for emails to work.

config.action_mailer.default_url_options = {host: "blazer.dokkuapp.com"}

Schedule checks to run (with cron, Heroku Scheduler, etc). The default options are every 5 minutes, 1 hour, or 1 day, which you can customize. For each of these options, set up a task to run.

rake blazer:run_checks SCHEDULE="5 minutes"
rake blazer:run_checks SCHEDULE="1 hour"
rake blazer:run_checks SCHEDULE="1 day"

You can also set up failing checks to be sent once a day (or whatever you prefer).

rake blazer:send_failing_checks

Here’s what it looks like with cron.

*/5 * * * * rake blazer:run_checks SCHEDULE="5 minutes"
0   * * * * rake blazer:run_checks SCHEDULE="1 hour"
30  7 * * * rake blazer:run_checks SCHEDULE="1 day"
0   8 * * * rake blazer:send_failing_checks

For Slack notifications, create an incoming webhook and set:

BLAZER_SLACK_WEBHOOK_URL=https://hooks.slack.com/...

Name the webhook “Blazer” and add a cool icon.

Authentication

Don’t forget to protect the dashboard in production.

Basic Authentication

Set the following variables in your environment or an initializer.

ENV["BLAZER_USERNAME"] = "andrew"
ENV["BLAZER_PASSWORD"] = "secret"

Devise

authenticate :user, ->(user) { user.admin? } do
  mount Blazer::Engine, at: "blazer"
end

Other

Specify a before_action method to run in blazer.yml.

before_action_method: require_admin

You can define this method in your ApplicationController.

def require_admin
  # depending on your auth, something like...
  redirect_to root_path unless current_user && current_user.admin?
end

Be sure to render or redirect for unauthorized users.

Permissions

PostgreSQL

Create a user with read-only permissions:

BEGIN;
CREATE ROLE blazer LOGIN PASSWORD 'secret';
GRANT CONNECT ON DATABASE dbname TO blazer;
GRANT USAGE ON SCHEMA public TO blazer;
GRANT SELECT ON ALL TABLES IN SCHEMA public TO blazer;
ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT SELECT ON TABLES TO blazer;
COMMIT;

MySQL

Create a user with read-only permissions:

CREATE USER 'blazer'@'127.0.0.1' IDENTIFIED BY 'secret';
GRANT SELECT, SHOW VIEW ON dbname.* TO 'blazer'@'127.0.0.1';
FLUSH PRIVILEGES;

Sensitive Data

If your database contains sensitive or personal data, check out Hypershield to shield it.

Encrypted Data

If you need to search encrypted data, use blind indexing.

You can have Blazer transform specific variables with:

Blazer.transform_variable = lambda do |name, value|
  value = User.generate_email_bidx(value) if name == "email_bidx"
  value
end

Queries

Variables

Create queries with variables.

SELECT * FROM users WHERE gender = {gender}

Use {start_time} and {end_time} for time ranges. Example

SELECT * FROM ratings WHERE rated_at >= {start_time} AND rated_at <= {end_time}

Smart Variables

Example

Suppose you have the query:

SELECT * FROM users WHERE occupation_id = {occupation_id}

Instead of remembering each occupation’s id, users can select occupations by name.

Add a smart variable with:

smart_variables:
  occupation_id: "SELECT id, name FROM occupations ORDER BY name ASC"

The first column is the value of the variable, and the second column is the label.

You can also use an array or hash for static data and enums.

smart_variables:
  period: ["day", "week", "month"]
  status: {0: "Active", 1: "Archived"}

Linked Columns

Example - title column

Link results to other pages in your apps or around the web. Specify a column name and where it should link to. You can use the value of the result with {value}.

linked_columns:
  user_id: "/admin/users/{value}"
  ip_address: "https://www.infosniper.net/index.php?ip_address={value}"

Smart Columns

Example - occupation_id column

Suppose you have the query:

SELECT name, city_id FROM users

See which city the user belongs to without a join.

smart_columns:
  city_id: "SELECT id, name FROM cities WHERE id IN {value}"

You can also use a hash for static data and enums.

smart_columns:
  status: {0: "Active", 1: "Archived"}

Caching

Blazer can automatically cache results to improve speed. It can cache slow queries:

cache:
  mode: slow
  expires_in: 60 # min
  slow_threshold: 15 # sec

Or it can cache all queries:

cache:
  mode: all
  expires_in: 60 # min

Of course, you can force a refresh at any time.

Charts

Blazer will automatically generate charts based on the types of the columns returned in your query.

Note: The order of columns matters.

Line Chart

There are two ways to generate line charts.

2+ columns - timestamp, numeric(s) - Example

SELECT date_trunc('week', created_at), COUNT(*) FROM users GROUP BY 1

3 columns - timestamp, string, numeric - Example

SELECT date_trunc('week', created_at), gender, COUNT(*) FROM users GROUP BY 1, 2

Column Chart

There are also two ways to generate column charts.

2+ columns - string, numeric(s) - Example

SELECT gender, COUNT(*) FROM users GROUP BY 1

3 columns - string, string, numeric - Example

SELECT gender, zip_code, COUNT(*) FROM users GROUP BY 1, 2

Scatter Chart

2 columns - both numeric - Example

SELECT x, y FROM table

Pie Chart

2 columns - string, numeric - and last column named pie - Example

SELECT gender, COUNT(*) AS pie FROM users GROUP BY 1

Maps

Columns named latitude and longitude or lat and lon or lat and lng - Example

SELECT name, latitude, longitude FROM cities

or a column named geojson

SELECT name, geojson FROM counties

To enable, get an access token from Mapbox and set ENV["MAPBOX_ACCESS_TOKEN"].

Targets

Use the column name target to draw a line for goals. Example

SELECT date_trunc('week', created_at), COUNT(*) AS new_users, 100000 AS target FROM users GROUP BY 1

Dashboards

Create a dashboard with multiple queries. Example

If the query has a chart, the chart is shown. Otherwise, you’ll see a table.

If any queries have variables, they will show up on the dashboard.

Checks

Checks give you a centralized place to see the health of your data. Example

Create a query to identify bad rows.

SELECT * FROM ratings WHERE user_id IS NULL /* all ratings should have a user */

Then create check with optional emails if you want to be notified. Emails are sent when a check starts failing, and when it starts passing again.

Cohorts

Create a cohort analysis from a simple SQL query. Example

Create a query with the comment /* cohort analysis */. The result should have columns named user_id and conversion_time and optionally cohort_time.

You can generate cohorts from the first conversion time:

/* cohort analysis */
SELECT user_id, created_at AS conversion_time FROM orders

(the first conversion isn’t counted in the first time period with this format)

Or from another time, like sign up:

/* cohort analysis */
SELECT users.id AS user_id, orders.created_at AS conversion_time, users.created_at AS cohort_time
FROM users LEFT JOIN orders ON orders.user_id = users.id

This feature requires PostgreSQL or MySQL 8.

Anomaly Detection

Blazer supports three different approaches to anomaly detection.

Prophet

Add prophet-rb to your Gemfile:

gem "prophet-rb"

And add to config/blazer.yml:

anomaly_checks: prophet

Trend

Trend uses an external service by default, but you can run it on your own infrastructure as well.

Add trend to your Gemfile:

gem "trend"

And add to config/blazer.yml:

anomaly_checks: trend

For the self-hosted API, create an initializer with:

Trend.url = "http://localhost:8000"

AnomalyDetection.rb

Add anomaly_detection to your Gemfile:

gem "anomaly_detection"

And add to config/blazer.yml:

anomaly_checks: anomaly_detection

Forecasting

Blazer supports for two different forecasting methods. Example

A forecast link will appear for queries that return 2 columns with types timestamp and numeric.

Prophet

Add prophet-rb to your Gemfile:

gem "prophet-rb", ">= 0.2.1"

And add to config/blazer.yml:

forecasting: prophet

Trend

Trend uses an external service by default, but you can run it on your own infrastructure as well.

Add trend to your Gemfile:

gem "trend"

And add to config/blazer.yml:

forecasting: trend

For the self-hosted API, create an initializer with:

Trend.url = "http://localhost:8000"

Uploads

Create database tables from CSV files. Example

Run:

rails generate blazer:uploads
rails db:migrate

And add to config/blazer.yml:

uploads:
  url: postgres://...
  schema: uploads
  data_source: main

This feature requires PostgreSQL. Create a new schema just for uploads.

CREATE SCHEMA uploads;

Data Sources

Blazer supports multiple data sources 🎉

Add additional data sources in config/blazer.yml:

data_sources:
  main:
    url: <%= ENV["BLAZER_DATABASE_URL"] %>
    # timeout, smart_variables, linked_columns, smart_columns
  catalog:
    url: <%= ENV["CATALOG_DATABASE_URL"] %>
    # ...
  redshift:
    url: <%= ENV["REDSHIFT_DATABASE_URL"] %>
    # ...

Full List

Amazon Athena
Amazon Redshift
Apache Drill
Apache Hive
Apache Ignite
Apache Spark
Cassandra
Druid
Elasticsearch
Google BigQuery
IBM DB2 and Informix
InfluxDB
MySQL
Neo4j
OpenSearch
Oracle
PostgreSQL
Presto
Salesforce
Socrata Open Data API (SODA)
Snowflake
SQLite
SQL Server

You can also create an adapter for any other data store.

Note: In the examples below, we recommend using environment variables for urls.

data_sources:
  my_source:
    url: <%= ENV["BLAZER_MY_SOURCE_URL"] %>

Amazon Athena

Add aws-sdk-athena and aws-sdk-glue to your Gemfile and set:

data_sources:
  my_source:
    adapter: athena
    database: database

    # optional settings
    output_location: s3://some-bucket/
    workgroup: primary
    access_key_id: ...
    secret_access_key: ...
    region: ...

Here’s an example IAM policy:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "athena:GetQueryExecution",
                "athena:GetQueryResults",
                "athena:StartQueryExecution"
            ],
            "Resource": [
                "arn:aws:athena:region:account-id:workgroup/primary"
            ]
        },
        {
            "Effect": "Allow",
            "Action": [
                "glue:GetTable",
                "glue:GetTables"
            ],
            "Resource": [
                "arn:aws:glue:region:account-id:catalog",
                "arn:aws:glue:region:account-id:database/default",
                "arn:aws:glue:region:account-id:table/default/*"
            ]
        }
    ]
}

You also need to configure S3 permissions.

Amazon Redshift

Add activerecord6-redshift-adapter or activerecord5-redshift-adapter to your Gemfile and set:

data_sources:
  my_source:
    url: redshift://user:password@hostname:5439/database

Use a read-only user.

Apache Drill

Add drill-sergeant to your Gemfile and set:

data_sources:
  my_source:
    adapter: drill
    url: http://hostname:8047

Use a read-only user.

Apache Hive

Add hexspace to your Gemfile and set:

data_sources:
  my_source:
    adapter: hive
    url: sasl://user:password@hostname:10000/database

Use a read-only user. Requires HiveServer2.

Apache Ignite

Add ignite-client to your Gemfile and set:

data_sources:
  my_source:
    url: ignite://user:password@hostname:10800

Use a read-only user (requires a third-party plugin).

Apache Spark

Add hexspace to your Gemfile and set:

data_sources:
  my_source:
    adapter: spark
    url: sasl://user:password@hostname:10000/database

Use a read-only user. Requires the Thrift server.

Cassandra

Add cassandra-driver (and sorted_set for Ruby 3+) to your Gemfile and set:

data_sources:
  my_source:
    url: cassandra://user:password@hostname:9042/keyspace

Use a read-only role.

Druid

Enable SQL support on the broker and set:

data_sources:
  my_source:
    adapter: druid
    url: http://hostname:8082

Use a read-only role.

Elasticsearch

Add elasticsearch to your Gemfile and set:

data_sources:
  my_source:
    adapter: elasticsearch
    url: http://user:password@hostname:9200

Use a read-only role.

Google BigQuery

Add google-cloud-bigquery to your Gemfile and set:

data_sources:
  my_source:
    adapter: bigquery
    project: your-project
    keyfile: path/to/keyfile.json

IBM DB2 and Informix

Add ibm_db to your Gemfile and set:

data_sources:
  my_source:
    url: ibm-db://user:password@hostname:50000/database

Use a read-only user.

InfluxDB

Add influxdb to your Gemfile and set:

data_sources:
  my_source:
    adapter: influxdb
    url: http://user:password@hostname:8086/database

Use a read-only user. Supports InfluxQL.

MySQL

Add mysql2 to your Gemfile (if it’s not there) and set:

data_sources:
  my_source:
    url: mysql2://user:password@hostname:3306/database

Use a read-only user.

Neo4j

Add neo4j-core to your Gemfile and set:

data_sources:
  my_source:
    adapter: neo4j
    url: http://user:password@hostname:7474

Use a read-only user.

OpenSearch

Add opensearch-ruby to your Gemfile and set:

data_sources:
  my_source:
    adapter: opensearch
    url: http://user:password@hostname:9200

Use a read-only user.

Oracle

Add activerecord-oracle_enhanced-adapter and ruby-oci8 to your Gemfile and set:

data_sources:
  my_source:
    url: oracle-enhanced://user:password@hostname:1521/database

Use a read-only user.

PostgreSQL

Add pg to your Gemfile (if it’s not there) and set:

data_sources:
  my_source:
    url: postgres://user:password@hostname:5432/database

Use a read-only user.

Presto

Add presto-client to your Gemfile and set:

data_sources:
  my_source:
    url: presto://user@hostname:8080/catalog

Use a read-only user.

Salesforce

Add restforce to your Gemfile and set:

data_sources:
  my_source:
    adapter: salesforce

And set the appropriate environment variables:

SALESFORCE_USERNAME="username"
SALESFORCE_PASSWORD="password"
SALESFORCE_SECURITY_TOKEN="security token"
SALESFORCE_CLIENT_ID="client id"
SALESFORCE_CLIENT_SECRET="client secret"
SALESFORCE_API_VERSION="41.0"

Use a read-only user. Supports SOQL.

Socrata Open Data API (SODA)

Set:

data_sources:
  my_source:
    adapter: soda
    url: https://soda.demo.socrata.com/resource/4tka-6guv.json
    app_token: ...

Supports SoQL.

Snowflake

First, install ODBC. For Homebrew, use:

brew install unixodbc

For Ubuntu, use:

sudo apt-get install unixodbc-dev

For Heroku, use the Apt buildpack and create an Aptfile with:

unixodbc-dev
https://sfc-repo.snowflakecomputing.com/odbc/linux/2.21.5/snowflake-odbc-2.21.5.x86_64.deb

This installs the driver at /app/.apt/usr/lib/snowflake/odbc/lib/libSnowflake.so

Then, download the Snowflake ODBC driver. Add odbc_adapter to your Gemfile and set:

data_sources:
  my_source:
    adapter: snowflake
    conn_str: Driver=/path/to/libSnowflake.so;uid=user;pwd=password;server=host.snowflakecomputing.com

Use a read-only role.

SQLite

Add sqlite3 to your Gemfile and set:

data_sources:
  my_source:
    url: sqlite3:path/to/database.sqlite3

SQL Server

Add tiny_tds and activerecord-sqlserver-adapter to your Gemfile and set:

data_sources:
  my_source:
    url: sqlserver://user:password@hostname:1433/database

Use a read-only user.

Creating an Adapter

Create an adapter for any data store with:

class FooAdapter < Blazer::Adapters::BaseAdapter
  # code goes here
end

Blazer.register_adapter "foo", FooAdapter

See the Presto adapter for a good example. Then use:

data_sources:
  my_source:
    adapter: foo
    url: http://user:password@hostname:9200/

Query Permissions

Blazer supports a basic permissions model.

Queries without a name are unlisted
Queries whose name starts with # are only listed to the creator
Queries whose name starts with * can only be edited by the creator

Learn SQL

Have team members who want to learn SQL? Here are a few great, free resources.

Useful Tools

For an easy way to group by day, week, month, and more with correct time zones, check out Groupdate.sql.

Standalone Version

Looking for a standalone version? Check out Ghost Blazer.

Performance

By default, queries take up a request while they are running. To run queries asynchronously, add to your config:

async: true

Note: Requires caching to be enabled. If you have multiple web processes, your app must use a centralized cache store like Memcached or Redis.

config.cache_store = :mem_cache_store

Archiving

Archive queries that haven’t been viewed in over 90 days.

rake blazer:archive_queries

Content Security Policy

If views are stuck with a Loading... message, there might be a problem with strict CSP settings in your app. This can be checked with Firefox or Chrome dev tools. You can allow Blazer to override these settings for its controllers with: