Datomic Flare for Ruby
A Ruby gem for interacting with Datomic through Datomic Flare.
This is not an official Datomic project or documentation and it is not affiliated with Datomic in any way.
TL;DR and Quick Start
gem 'datomic-flare', '~> 1.0.1'
require 'datomic-flare'
client = Flare.new(credentials: { address: 'http://localhost:3042' })
client.dsl.transact_schema!(
{
book: {
title: { type: :string, doc: 'The title of the book.' },
genre: { type: :string, doc: 'The genre of the book.' }
}
}
)
client.dsl.assert_into!(
:book,
{
title: 'The Tell-Tale Heart',
genre: 'Horror'
}
)
client.dsl.query(
datalog: <<~EDN
[:find ?e ?title ?genre
:where [?e :book/title ?title]
[?e :book/genre ?genre]]
EDN
)
[[4611681620380877802, 'The Tell-Tale Heart', 'Horror']]
Flare
Creating a Client
require 'datomic-flare'
client = Flare.new(credentials: { address: 'http://localhost:3042' })
Meta
client.
{
'meta' =>
{
'at' => '2024-09-29T14:09:06.891354452Z',
'mode' => 'peer',
'took' => { 'milliseconds' => 0.439342 }
},
'data' =>
{
'mode' => 'peer',
'datomic-flare' => '1.0.0',
'org.clojure/clojure' => '1.12.0',
'com.datomic/peer' => '1.0.7187',
'com.datomic/client-pro' => '1.0.81'
}
}
Flare DSL
It provides a Ruby-familiar approach to working with Datomic. It brings Ruby’s conventions and idioms while preserving Datomic’s data-first principles and terminology.
This approach should be cozy to those who are familiar with Ruby.
Learn more about Ruby and The Rails Doctrine:
Creating a Database
client.dsl.create_database!('radioactive')
true
Deleting a Database
client.dsl.destroy_database!('radioactive')
true
Listing Databases
client.dsl.databases
['my-datomic-database']
Transacting Schema
Like CREATE TABLE in SQL databases or defining document or record structures in other databases.
client.dsl.transact_schema!(
{
book: {
title: { type: :string, doc: 'The title of the book.' },
genre: { type: :string, doc: 'The genre of the book.' },
published_at_year: { type: :long, doc: 'The year the book was first published.' }
}
}
)
true
Checking Schema
Like SHOW COLUMNS FROM in SQL databases or checking document or record structures in other databases.
client.dsl.schema
{
book: {
published_at_year: {
type: :long,
cardinality: :one,
doc: 'The year the book was first published.',
unique: false,
index: false,
history: true
},
title: {
type: :string,
cardinality: :one,
doc: 'The title of the book.',
unique: false,
index: false,
history: true
},
genre: {
type: :string,
cardinality: :one,
doc: 'The genre of the book.',
unique: false,
index: false,
history: true
}
}
}
Asserting Facts
Like INSERT INTO in SQL databases or creating a new document or record in other databases.
client.dsl.assert_into!(
:book,
{
title: 'Pride and Prejudice',
genre: 'Romance',
published_at_year: 1813
}
)
4611681620380877802
client.dsl.assert_into!(
:book,
[{
title: 'Near to the Wild Heart',
genre: 'Novel',
published_at_year: 1943
},
{
title: 'A Study in Scarlet',
genre: 'Detective',
published_at_year: 1887
},
{
title: 'The Tell-Tale Heart',
genre: 'Horror',
published_at_year: 1843
}]
)
[4611681620380877804, 4611681620380877805, 4611681620380877806]
Reading Data by Entity
Like SELECT in SQL databases or querying documents or records in other databases.
client.dsl.find_by_entity_id(4611681620380877804)
{
book: {
title: 'Near to the Wild Heart',
genre: 'Novel',
published_at_year: 1943,
_id: 4611681620380877804
}
}
Reading Data by Querying
Like SELECT in SQL databases or querying documents or records in other databases.
client.dsl.query(
datalog: <<~EDN
[:find ?e ?title ?genre ?year
:where [?e :book/title ?title]
[?e :book/genre ?genre]
[?e :book/published_at_year ?year]]
EDN
)
[[4611681620380877805, 'A Study in Scarlet', 'Detective', 1887],
[4611681620380877804, 'Near to the Wild Heart', 'Novel', 1943],
[4611681620380877806, 'The Tell-Tale Heart', 'Horror', 1843],
[4611681620380877802, 'Pride and Prejudice', 'Romance', 1813]]
client.dsl.query(
params: ['The Tell-Tale Heart'],
datalog: <<~EDN
[:find ?e ?title ?genre ?year
:in $ ?title
:where [?e :book/title ?title]
[?e :book/genre ?genre]
[?e :book/published_at_year ?year]]
EDN
)
[[4611681620380877806, 'The Tell-Tale Heart', 'Horror', 1843]]
Accumulating Facts
Like UPDATE in SQL databases or updating documents or records in other databases. However, Datomic never updates data. It is an immutable database that only accumulates new facts or retracts past facts.
client.dsl.assert_into!(
:book, { _id: 4611681620380877806, genre: 'Gothic' }
)
4611681620380877806
Retracting Facts
Like DELETE in SQL databases or deleting documents or records in other databases. However, Datomic never deletes data. It is an immutable database that only accumulates new facts or retracts past facts.
Retract the value of an attribute:
client.dsl.retract_from!(
:book, { _id: 4611681620380877806, genre: 'Gothic' }
)
true
Retract an attribute:
client.dsl.retract_from!(
:book, { _id: 4611681620380877804, genre: nil }
)
true
Retract an entity:
client.dsl.retract_from!(
:book, { _id: 4611681620380877805 }
)
true
Flare API
It provides methods that mirror Datomic's APIs. Most interactions use EDN, closely following Datomic’s documentation.
This approach should be familiar to those who know Datomic concepts and APIs.
Learn more about Clojure and Datomic:
Creating a Database
client.api.create_database!({ name: 'fireball' })['data']
true
Deleting a Database
client.api.delete_database!({ name: 'fireball' })['data']
true
Listing Databases
# Flare on Peer Mode
client.api.get_database_names['data']
# Flare on Client Mode
client.api.list_databases['data']
['my-datomic-database']
Transacting Schema
client.api.transact!(
{ data: <<~EDN
[{:db/ident :book/title
:db/valueType :db.type/string
:db/cardinality :db.cardinality/one
:db/doc "The title of the book."}
{:db/ident :book/genre
:db/valueType :db.type/string
:db/cardinality :db.cardinality/one
:db/doc "The genre of the book."}
{:db/ident :book/published_at_year
:db/valueType :db.type/long
:db/cardinality :db.cardinality/one
:db/doc "The year the book was first published."}]
EDN
}
)['data']
{
'db-before' => 'datomic.db.Db@7740573a',
'db-after' => 'datomic.db.Db@7898935d',
'tx-data' =>
[[13194139534312, 50, '2024-09-29T14:09:07.059Z', 13194139534312, true],
[72, 10, ':book/title', 13194139534312, true],
[72, 40, 23, 13194139534312, true],
[72, 41, 35, 13194139534312, true],
[72, 62, 'The title of the book.', 13194139534312, true],
[73, 10, ':book/genre', 13194139534312, true],
[73, 40, 23, 13194139534312, true],
[73, 41, 35, 13194139534312, true],
[73, 62, 'The genre of the book.', 13194139534312, true],
[74, 10, ':book/published_at_year', 13194139534312, true],
[74, 40, 22, 13194139534312, true],
[74, 41, 35, 13194139534312, true],
[74, 62, 'The year the book was first published.', 13194139534312, true],
[0, 13, 72, 13194139534312, true],
[0, 13, 73, 13194139534312, true],
[0, 13, 74, 13194139534312, true]],
'tempids' =>
{
'-9223300668110558605' => 72,
'-9223300668110558604' => 73,
'-9223300668110558603' => 74
}
}
Checking Schema
client.api.q(
{
inputs: [{ database: { latest: true } }],
query: <<~EDN
[:find
?e ?ident ?value_type ?cardinality ?doc
?unique ?index ?no_history
:in $
:where
[?e :db/ident ?ident]
[?e :db/valueType ?value_type_id]
[?value_type_id :db/ident ?value_type]
[?e :db/cardinality ?cardinality_id]
[?cardinality_id :db/ident ?cardinality]
[(get-else $ ?e :db/doc "") ?doc]
[(get-else $ ?e :db/unique -1) ?unique_id]
[(get-else $ ?unique_id :db/ident false) ?unique]
[(get-else $ ?e :db/index false) ?index]
[(get-else $ ?e :db/noHistory false) ?no_history]]
EDN
}
)['data'].filter do |datom|
!%w[
db
db.alter db.attr db.bootstrap db.cardinality db.entity db.excise
db.fn db.install db.lang db.part db.sys db.type db.unique
fressian
].include?(datom[1].split('/').first)
end
[[74,
'book/published_at_year',
'db.type/long',
'db.cardinality/one',
'The year the book was first published.',
false,
false,
false],
[72,
'book/title',
'db.type/string',
'db.cardinality/one',
'The title of the book.',
false,
false,
false],
[73,
'book/genre',
'db.type/string',
'db.cardinality/one',
'The genre of the book.',
false,
false,
false]]
Asserting Facts
client.api.transact!(
{ data: <<~EDN
[{:db/id -1
:book/title "Pride and Prejudice"
:book/genre "Romance"
:book/published_at_year 1813}]
EDN
}
)['data']
{
'db-before' => 'datomic.db.Db@4f9110f1',
'db-after' => 'datomic.db.Db@1b8a609c',
'tx-data' =>
[[13194139534313, 50, '2024-09-29T14:09:07.167Z', 13194139534313, true],
[4611681620380877802, 72, 'Pride and Prejudice', 13194139534313, true],
[4611681620380877802, 73, 'Romance', 13194139534313, true],
[4611681620380877802, 74, 1813, 13194139534313, true]],
'tempids' => { '-1' => 4611681620380877802 }
}
client.api.transact!(
{ data: <<~EDN
[{:db/id -1
:book/title "Near to the Wild Heart"
:book/genre "Novel"
:book/published_at_year 1943}
{:db/id -2
:book/title "A Study in Scarlet"
:book/genre "Detective"
:book/published_at_year 1887}
{:db/id -3
:book/title "The Tell-Tale Heart"
:book/genre "Horror"
:book/published_at_year 1843}]
EDN
}
)['data']
{
'db-before' => 'datomic.db.Db@6e061d50',
'db-after' => 'datomic.db.Db@523869b6',
'tx-data' =>
[[13194139534315, 50, '2024-09-29T14:09:07.207Z', 13194139534315, true],
[4611681620380877804, 72, 'Near to the Wild Heart', 13194139534315, true],
[4611681620380877804, 73, 'Novel', 13194139534315, true],
[4611681620380877804, 74, 1943, 13194139534315, true],
[4611681620380877805, 72, 'A Study in Scarlet', 13194139534315, true],
[4611681620380877805, 73, 'Detective', 13194139534315, true],
[4611681620380877805, 74, 1887, 13194139534315, true],
[4611681620380877806, 72, 'The Tell-Tale Heart', 13194139534315, true],
[4611681620380877806, 73, 'Horror', 13194139534315, true],
[4611681620380877806, 74, 1843, 13194139534315, true]],
'tempids' =>
{
'-1' => 4611681620380877804,
'-2' => 4611681620380877805,
'-3' => 4611681620380877806
}
}
Reading Data by Entity
client.api.entity(
{
database: { latest: true },
id: 4611681620380877804
}
)['data']
{
':book/title' => 'Near to the Wild Heart',
':book/genre' => 'Novel',
':book/published_at_year' => 1943,
':db/id' => 4611681620380877804
}
Reading Data by Querying
client.api.q(
{
inputs: [{ database: { latest: true } }],
query: <<~EDN
[:find ?e ?title ?genre ?year
:where [?e :book/title ?title]
[?e :book/genre ?genre]
[?e :book/published_at_year ?year]]
EDN
}
)['data']
[[4611681620380877805, 'A Study in Scarlet', 'Detective', 1887],
[4611681620380877804, 'Near to the Wild Heart', 'Novel', 1943],
[4611681620380877806, 'The Tell-Tale Heart', 'Horror', 1843],
[4611681620380877802, 'Pride and Prejudice', 'Romance', 1813]]
client.api.q(
{
inputs: [
{ database: { latest: true } },
'The Tell-Tale Heart'
],
query: <<~EDN
[:find ?e ?title ?genre ?year
:in $ ?title
:where [?e :book/title ?title]
[?e :book/genre ?genre]
[?e :book/published_at_year ?year]]
EDN
}
)['data']
[[4611681620380877806, 'The Tell-Tale Heart', 'Horror', 1843]]
Accumulating Facts
client.api.transact!(
{ data: <<~EDN
[{:db/id 4611681620380877806 :book/genre "Gothic"}]
EDN
}
)['data']
{
'db-before' => 'datomic.db.Db@15e9ed98',
'db-after' => 'datomic.db.Db@29007ec5',
'tx-data' =>
[[13194139534319, 50, '2024-09-29T14:09:07.420Z', 13194139534319, true],
[4611681620380877806, 73, 'Gothic', 13194139534319, true],
[4611681620380877806, 73, 'Horror', 13194139534319, false]],
'tempids' => {}
}
Retracting Facts
Retract the value of an attribute:
client.api.transact!(
{ data: <<~EDN
[[:db/retract 4611681620380877806 :book/genre "Gothic"]]
EDN
}
)['data']
{
'db-before' => 'datomic.db.Db@27c78595',
'db-after' => 'datomic.db.Db@5d2ff139',
'tx-data' =>
[[13194139534320, 50, '2024-09-29T14:09:07.470Z', 13194139534320, true],
[4611681620380877806, 73, 'Gothic', 13194139534320, false]],
'tempids' => {}
}
Retract an attribute:
client.api.transact!(
{ data: <<~EDN
[[:db/retract 4611681620380877804 :book/genre]]
EDN
}
)['data']
{
'db-before' => 'datomic.db.Db@23f815b5',
'db-after' => 'datomic.db.Db@39d9b51',
'tx-data' =>
[[13194139534321, 50, '2024-09-29T14:09:07.510Z', 13194139534321, true],
[4611681620380877804, 73, 'Novel', 13194139534321, false]],
'tempids' => {}
}
Retract an entity:
client.api.transact!(
{ data: <<~EDN
[[:db/retractEntity 4611681620380877805]]
EDN
}
)['data']
{
'db-before' => 'datomic.db.Db@66fa8fae',
'db-after' => 'datomic.db.Db@60c2b7f2',
'tx-data' =>
[[13194139534322, 50, '2024-09-29T14:09:07.550Z', 13194139534322, true],
[4611681620380877805, 72, 'A Study in Scarlet', 13194139534322, false],
[4611681620380877805, 73, 'Detective', 13194139534322, false],
[4611681620380877805, 74, 1887, 13194139534322, false]],
'tempids' => {}
}
Development
bundle
rubocop -A
Publish to RubyGems
gem build datomic-flare.gemspec
gem signin
gem push datomic-flare-1.0.1.gem
Setup for Tests and Documentation
Tests run against real Datomic databases, and documentation (README) is generated by interacting with real Datomic databases.
To accomplish that, we need to have Datomic and Flare running.
TL;DR:
git clone https://github.com/gbaptista/datomic-pro-docker.git
cd datomic-pro-docker
cp compose/flare-dev.yml docker-compose.yml
docker compose up -d datomic-storage
docker compose run datomic-tools psql \
-f bin/sql/postgres-table.sql \
-h datomic-storage \
-U datomic-user \
-d my-datomic-storage
docker compose up -d datomic-transactor
docker compose run datomic-tools clojure -M -e "$(cat <<'CLOJURE'
(require '[datomic.api :as d])
(d/create-database "datomic:sql://my-datomic-database?jdbc:postgresql://datomic-storage:5432/my-datomic-storage?user=datomic-user&password=unsafe")
(d/create-database "datomic:sql://my-datomic-database-test?jdbc:postgresql://datomic-storage:5432/my-datomic-storage?user=datomic-user&password=unsafe")
(d/create-database "datomic:sql://my-datomic-database-test-green?jdbc:postgresql://datomic-storage:5432/my-datomic-storage?user=datomic-user&password=unsafe")
(System/exit 0)
CLOJURE
)"
docker compose up -d datomic-peer-server
docker compose up -d datomic-flare-peer datomic-flare-client
curl -s http://localhost:3042/meta \
-X GET \
-H "Content-Type: application/json" \
| jq
{
"data": {
"mode": "peer"
}
}
curl -s http://localhost:3043/meta \
-X GET \
-H "Content-Type: application/json" \
| jq
{
"data": {
"mode": "client"
}
}
You are ready to run tests and generate documentation.
Detailed instructions:
Clone the datomic-pro-docker repository and copy the Docker Compose template:
git clone https://github.com/gbaptista/datomic-pro-docker.git
cd datomic-pro-docker
cp compose/flare-dev.yml docker-compose.yml
Start PostgreSQL as Datomic's storage service:
docker compose up -d datomic-storage
docker compose logs -f datomic-storage
Create the table for Datomic databases:
docker compose run datomic-tools psql \
-f bin/sql/postgres-table.sql \
-h datomic-storage \
-U datomic-user \
-d my-datomic-storage
You will be prompted for a password, which is unsafe.
Start the Datomic Transactor:
docker compose up -d datomic-transactor
docker compose logs -f datomic-transactor
Create the following databases:
my-datomic-databasemy-datomic-database-testmy-datomic-database-test-green
docker compose run datomic-tools clojure -M -e "$(cat <<'CLOJURE'
(require '[datomic.api :as d])
(d/create-database "datomic:sql://my-datomic-database?jdbc:postgresql://datomic-storage:5432/my-datomic-storage?user=datomic-user&password=unsafe")
(d/create-database "datomic:sql://my-datomic-database-test?jdbc:postgresql://datomic-storage:5432/my-datomic-storage?user=datomic-user&password=unsafe")
(d/create-database "datomic:sql://my-datomic-database-test-green?jdbc:postgresql://datomic-storage:5432/my-datomic-storage?user=datomic-user&password=unsafe")
(System/exit 0)
CLOJURE
)"
Start the Peer Server:
docker compose up -d datomic-peer-server
docker compose logs -f datomic-peer-server
Start 2 instances of Flare, one in Peer Mode and another in Client Mode:
docker compose up -d datomic-flare-peer datomic-flare-client
docker compose logs -f datomic-flare-peer
docker compose logs -f datomic-flare-client
You should be able to request both:
Datomic Flare in Peer Mode:
curl -s http://localhost:3042/meta \
-X GET \
-H "Content-Type: application/json" \
| jq
{
"data": {
"mode": "peer"
}
}
Datomic Flare in Client Mode:
curl -s http://localhost:3043/meta \
-X GET \
-H "Content-Type: application/json" \
| jq
{
"data": {
"mode": "client"
}
}
You are ready to run tests and generate documentation.
Running Tests
Tests run against real Datomic databases, so complete the Setup for Tests and Documentation first.
cp .env.example .env
bundle exec rspec
Updating the README
Documentation (README) is generated by interacting with real Datomic databases, so complete the Setup for Tests and Documentation first.
Update the docs/templates/*.md files, and then:
cp .env.example .env
bundle exec ruby ports/cli.rb docs:generate
Trick for automatically updating the README.md when docs/templates/*.md files change:
sudo pacman -S inotify-tools # Arch / Manjaro
sudo apt-get install inotify-tools # Debian / Ubuntu / Raspberry Pi OS
sudo dnf install inotify-tools # Fedora / CentOS / RHEL
while inotifywait -e modify docs/templates/*; \
do bundle exec ruby ports/cli.rb docs:generate; \
done
Trick for Markdown Live Preview:
pip install -U markdown_live_preview
mlp README.md -p 8042 --no-follow