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import * as Sequelize from 'sequelize'
import { isHostValid, logger } from '../../helpers'
import { SERVERS_SCORE } from '../../initializers'
import { addMethodsToModel } from '../utils'
import { ServerAttributes, ServerInstance, ServerMethods } from './server-interface'
let Server: Sequelize.Model<ServerInstance, ServerAttributes>
let updateServersScoreAndRemoveBadOnes: ServerMethods.UpdateServersScoreAndRemoveBadOnes
export default function (sequelize: Sequelize.Sequelize, DataTypes: Sequelize.DataTypes) {
Server = sequelize.define<ServerInstance, ServerAttributes>('Server',
{
host: {
type: DataTypes.STRING,
allowNull: false,
validate: {
isHost: value => {
const res = isHostValid(value)
if (res === false) throw new Error('Host not valid.')
}
}
},
score: {
type: DataTypes.INTEGER,
defaultValue: SERVERS_SCORE.BASE,
allowNull: false,
validate: {
isInt: true,
max: SERVERS_SCORE.MAX
}
}
},
{
indexes: [
{
fields: [ 'host' ],
unique: true
},
{
fields: [ 'score' ]
}
]
}
)
const classMethods = [
updateServersScoreAndRemoveBadOnes
]
addMethodsToModel(Server, classMethods)
return Server
}
// ------------------------------ Statics ------------------------------
updateServersScoreAndRemoveBadOnes = function (goodServers: number[], badServers: number[]) {
logger.info('Updating %d good servers and %d bad servers scores.', goodServers.length, badServers.length)
if (goodServers.length !== 0) {
incrementScores(goodServers, SERVERS_SCORE.BONUS).catch(err => {
logger.error('Cannot increment scores of good servers.', err)
})
}
if (badServers.length !== 0) {
incrementScores(badServers, SERVERS_SCORE.PENALTY)
.then(() => removeBadServers())
.catch(err => {
if (err) logger.error('Cannot decrement scores of bad servers.', err)
})
}
}
// ---------------------------------------------------------------------------
// Remove servers with a score of 0 (too many requests where they were unreachable)
async function removeBadServers () {
try {
const servers = await listBadServers()
const serversRemovePromises = servers.map(server => server.destroy())
await Promise.all(serversRemovePromises)
const numberOfServersRemoved = servers.length
if (numberOfServersRemoved) {
logger.info('Removed %d servers.', numberOfServersRemoved)
} else {
logger.info('No need to remove bad servers.')
}
} catch (err) {
logger.error('Cannot remove bad servers.', err)
}
}
function incrementScores (ids: number[], value: number) {
const update = {
score: Sequelize.literal('score +' + value)
}
const options = {
where: {
id: {
[Sequelize.Op.in]: ids
}
},
// In this case score is a literal and not an integer so we do not validate it
validate: false
}
return Server.update(update, options)
}
function listBadServers () {
const query = {
where: {
score: {
[Sequelize.Op.lte]: 0
}
}
}
return Server.findAll(query)
}
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