init checkin.

Author: ycombinator

.gitignore

@@ -12,3 +12,5 @@ logs
 results
 
 npm-debug.log
+
+node_modules/

README.md

@@ -1,4 +1,47 @@
-state-machine
-=============
+# State machine as a service
 
-State machine as a service
+Applications sometimes find themselves managing a process flow comprising of many process states and decisions that move the process along from one state to another. For example, consider a user registration process. When the application creates a new user, that user may start off in a *UNVERIFIED* state. When the application verifies the user's email address, the user may move to a *VERIFIED* state. On the other hand, if sufficient time passes and the user is still in the *UNVERIFIED* state, the application may choose to move the user to a *EXPIRED* state.
+
+Applications with such needs will end up implementing a state machine to manage the process flow. This service aims to save applications from that implementation effort. Using this service your application need only define the state machine that reflects the process flow and then tell the service each time a decision is made in the process. The service will take care of transitioning to the next state in the flow. Furthermore, the application can store arbitraty data along with each state.
+
+# Usage
+The service is currently provided as a REST API. 
+
+## REST API
+
+### Resources
+
+#### State Machines
+
+##### Create a new state machine
+
+###### Request
+
+    POST {baseuri}/v1/state-machines
+
+    {
+      "initialState": "foo",
+      "states": {
+        "foo": {
+          "transitions": [
+            { "input": "/1/","nextState": "bar" },
+            { "input": "/2/","nextState": "baz" }
+          ]
+        },
+        "bar": {
+          "transitions": []
+        },
+        "baz": {}
+      }
+    }
+
+###### Response (upon successful creation)
+
+    201 Created
+    Location: {baseuri}/v1/state-machine/2345
+
+    {
+      "links": {
+        "self": "{baseuri}/v1/state-machine/2345"
+      }
+    }

bin/update_db_schema.js

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+var config = require('config'),
+    childProcess = require('child_process'),
+    os = require('os'),
+    fs = require('fs')
+
+var dbConfig = {
+  dev: {
+    driver: 'pg',
+    user: config.db.username,
+    password: config.db.password,
+    host: config.db.host,
+    database: config.db.name
+  }
+}
+
+var dbConfigTempFilePath = os.tmpdir() + '/database.json'
+fs.writeFile(dbConfigTempFilePath, JSON.stringify(dbConfig), function(err) {
+
+  if (err) {
+    console.error('Could not create database config file. Aborting.')
+    process.exit(1)
+  }
+
+  var cmd = 'node_modules/db-migrate/bin/db-migrate --config ' + dbConfigTempFilePath + ' up'
+  childProcess.exec(cmd, function(err, stdout, stderr) {
+
+    console.log(stdout)
+    if (err) {
+      console.error(stderr)
+    }
+
+    fs.unlinkSync(dbConfigTempFilePath)
+
+  })
+
+})

config/default.js

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+var matches = []
+if (process.env.DATABASE_URL) {
+
+  var dbUrlRegex = /([^:]+):\/\/([^:]+):([^@]+)@([^:]+):([\d]+)\/(.+)/
+  matches = process.env.DATABASE_URL.match(dbUrlRegex)
+
+}
+
+module.exports = {
+  db: {
+    dialect: matches[1] || 'postgres',
+    name: matches[6] || 'statemachine',
+    username: matches[2] || 'statemachine',
+    password: matches[3] || '',
+    host: matches[4] || 'localhost',
+    port: matches[5] || 5432,
+    logging: console.log
+  },
+  restapi: {
+    port: process.env.PORT || 8080,
+    baseuri: 'http://localhost:8080'
+  }
+}

config/runtime.json

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+{}

lib/db.js

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+var config = require('config'),
+    sequelize = require('sequelize')
+
+module.exports = new sequelize(config.db.name, config.db.username, config.db.password, {
+  host: config.db.host,
+  port: config.db.port,
+  dialect: config.db.dialect,
+  omitNull: true,
+  define: {
+    syncOnAssociation: false,
+    underscored: true
+  },
+  logging: config.db.logging
+})

migrations/20130425004809-init.js

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+var dbm = require('db-migrate'),
+    async = require('async');
+var type = dbm.dataType;
+
+exports.up = function(db, callback) {
+  async.series([
+    db.createTable.bind(db, 'state_machines', {
+      id: { type: 'int', primaryKey: true, autoIncrement: true },
+      current_state_id: { type: 'int' },
+      created_at: 'datetime',
+      updated_at: 'datetime'
+    }),
+    db.createTable.bind(db, 'states', {
+      id: { type: 'int', primaryKey: true, autoIncrement: true },
+      name: { type: 'string', notNull: true },
+      state_machine_id: { type: 'int', notNull: true },
+      data: { type: 'text' },
+      created_at: 'datetime',
+      updated_at: 'datetime'
+    }),
+    db.createTable.bind(db, 'transitions', {
+      id: { type: 'int', primaryKey: true, autoIncrement: true },
+      state_id: { type: 'int', notNull: true },
+      input: { type: 'string', notNull: true },
+      next_state_id: { type: 'int', notNull: true },
+      created_at: 'datetime',
+      updated_at: 'datetime'
+    }),
+    db.runSql.bind(db, 'ALTER TABLE state_machines ADD CONSTRAINT fk_state_id FOREIGN KEY (current_state_id) REFERENCES states(id)'),
+    db.runSql.bind(db, 'ALTER TABLE states ADD CONSTRAINT fk_state_machine_id FOREIGN KEY (state_machine_id) REFERENCES state_machines(id)'),
+    db.runSql.bind(db, 'ALTER TABLE transitions ADD CONSTRAINT fk_state_id FOREIGN KEY (state_id) REFERENCES states(id)'),
+    db.runSql.bind(db, 'ALTER TABLE transitions ADD CONSTRAINT fk_next_state_id FOREIGN KEY (next_state_id) REFERENCES states(id)')
+  ], callback)
+};
+
+exports.down = function(db, callback) {
+  async.series([
+    db.dropTable.bind(db, 'transitions'),
+    db.dropTable.bind(db, 'states'),
+    db.dropTable.bind(db, 'state_machines')
+  ], callback)
+};

models/index.js

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+module.exports = require('requireindex')(__dirname);

models/state.js

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+var sequelize = require('sequelize'),
+    db = require('../lib/db.js')
+
+var State = db.define('states', {
+  name: sequelize.STRING,
+  data: sequelize.TEXT
+})
+
+module.exports = State

models/state_machine.js

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+var sequelize = require('sequelize'),
+    db = require('../lib/db.js'),
+    State = require('./state.js')
+
+var StateMachine = db.define('state_machines', {
+})
+
+StateMachine.hasOne(State, { foreignKey: 'current_state_id' })
+
+StateMachine.hasMany(State)
+State.belongsTo(StateMachine)
+
+module.exports = StateMachine

models/transition.js

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+var sequelize = require('sequelize'),
+    db = require('../lib/db.js'),
+    State = require('./state.js')
+
+var Transition = db.define('transitions', {
+  input: { type: sequelize.STRING, notNull: true }
+})
+
+Transition.belongsTo(State, { as: 'State', foreignKey: 'state_id' })
+State.hasMany(Transition, { foreignKey: 'state_id'})
+
+Transition.belongsTo(State, { as: 'NextState', foreignKey: 'next_state_id' })
+
+module.exports = Transition

package.json

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+{
+  "name": "state-machine",
+  "version": "0.0.1",
+  "private": false,
+  "dependencies": {
+    "async": "0.2.7",
+    "config": "0.4.22",
+    "date-utils": "1.2.12",
+    "db-migrate": "0.4.1",
+    "pg": "1.0.0",
+    "requireindex": "1.0.0",
+    "restify": "2.3.5",
+    "sequelize": "1.6.0",
+    "sprintf": "0.1.1"
+  },
+  "engines": {
+    "node": "0.10.x",
+    "npm": "1.2.x"
+  },
+  "license": "MIT"
+}

restapi/resources/index.js

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+module.exports = require('requireindex')(__dirname);

restapi/resources/v1/index.js

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+module.exports = require('requireindex')(__dirname);