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

• 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
• Queries
• Charts
• Dashboards
• Checks
• Cohorts
• Anomaly Detection
• Forecasting
• Uploads
• Data Sources
• Query Permissions

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.

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.

Don’t forget to protect the dashboard in production.

Set the following variables in your environment or an initializer.

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

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

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.

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;

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;

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

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

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}

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"}

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}"

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"}

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.

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

Note: The order of columns matters.

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

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

2 columns - both numeric - Example

SELECT x, y FROM table

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

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

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"].

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

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 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.

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.

Blazer supports three different approaches to anomaly detection.

Add prophet-rb to your Gemfile:

gem "prophet-rb"

And add to config/blazer.yml:

anomaly_checks: prophet

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"

Add anomaly_detection to your Gemfile:

gem "anomaly_detection"

And add to config/blazer.yml:

anomaly_checks: anomaly_detection

Blazer supports for two different forecasting methods. Example

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

Add prophet-rb to your Gemfile:

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

And add to config/blazer.yml:

forecasting: prophet

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"

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;

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"] %>
    # ...

• 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"] %>

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.

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.

Add drill-sergeant to your Gemfile and set:

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

Use a read-only user.

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.

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).

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.

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.

Enable SQL support on the broker and set:

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

Use a read-only role.

Add elasticsearch to your Gemfile and set:

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

Use a read-only role.

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

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

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.

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.

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.

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.

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.

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.

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.

Add presto-client to your Gemfile and set:

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

Use a read-only user.

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.

Set:

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

Supports SoQL.

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.

Add sqlite3 to your Gemfile and set:

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

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.

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/

Blazer supports a basic permissions model.

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

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

• The Data School
• SQLBolt

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

Looking for a standalone version? Check out Ghost Blazer.

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

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

rake blazer:archive_queries

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:

override_csp: true

Maps now use Mapbox GL JS v1 instead of Mapbox.js, which affects Mapbox billing.

Custom adapters now need to specify how to quote variables in queries (there is no longer a default)

class FooAdapter < Blazer::Adapters::BaseAdapter
  def quoting
    :backslash_escape # single quote strings and convert ' to \' and \ to \\
    # or
    :single_quote_escape # single quote strings and convert ' to ''
    # or
    ->(value) { ... } # custom method
  end
end

To archive queries, create a migration

rails g migration add_status_to_blazer_queries

with:

add_column :blazer_queries, :status, :string
Blazer::Query.update_all(status: "active")

To use Slack notifications, create a migration

rails g migration add_slack_channels_to_blazer_checks

with:

add_column :blazer_checks, :slack_channels, :text

View the changelog

Blazer uses a number of awesome open source projects, including Rails, Vue.js, jQuery, Bootstrap, Selectize, StickyTableHeaders, Stupid jQuery Table Sort, and Date Range Picker.

Demo data from MovieLens.

That’s awesome! Here are a few ways you can help:

• Report bugs
• Fix bugs and submit pull requests
• Write, clarify, or fix documentation
• Suggest or add new features

Check out the dev app to get started.