redis-wart

redis-wart

W - Widely
A - Accessible
R - Redis
T - Threading
S - System
A simple interpreter designed to process data sitting in redis.

Each wart in a cluster checks in redis for work to do. If it finds a stopped thread or a dead thread it takes the thread and runs it locally. There are also jobs which instead of continuously running they execute on a cron schedule.

Runtime params

• cluster-name - name of cluster
• wart-name - name of the wart
• redis-address - address to redis server
• redis-password - password for redis server
• scripts - scripts to register
• run-now - run registered scripts on this wart immediately

Getting dependencies

Requires a version of go that supports go.mod

• go get

Get up and running

• Build it
  • make build
• Build and run it
  • make run
• You can get started using an example config as such
  • ./bin/wart --config wart1.config
• Or you can pass in through runtime params
  • ./bin/wart --redis-address=<address> --redis-password=<password> --wart-name=wart1
• Or run through a docker container
  • docker run jaeg/redis-wart:latest --redis-address=<address> --redis-password=<password> --wart-name=wart1
• You can also tell it to load a script on start like this
  • ./bin/wart --redis-address=<address> --redis-password=<password> --wart-name=wart1 --scripts examples/hello.js
  • docker run jaeg/redis-wart:latest --redis-address=<address> --redis-password=<password> --wart-name=wart1 --scripts examples/hello.js

Javascript implementation

Wart's Javascript implementation is based on Otto. Each thread maintains its own scope. When a thread starts it runs the entire script. It then runs init() if present in the source code. If present a thread will call main() after confirming the thread is still running.

Extra Functions Available to scripts

Env

• env.Get(key)
  • returns string or undefined if key does not exist
• env.Set(key,value)
  • returns null or error if there is one
• env.Unset(key)
  • returns null or error if there is one

Wart

• wart.Name
  • returns string
• wart.Cluster
  • returns string
• wart.ShuttingDown - It is suggested that if you have code that loops you also check this to make sure the code end cleanly.
  • returns bool

Thread

• thread.Key
  • returns string
• thread.State()
  • returns string
• thread.Status()
  • returns string
• thread.Stopped - It is suggested that if you have code that loops you also check this to make sure the code end cleanly.
  • returns bool
• thread.Disable() - Disables the thread completely
  • returns nothing
• thread.Stop() - Stops the thread causing another node to possibly pick it up
  • returns nothing

Job

• job.Key
  • returns string
• job.State()
  • returns string
• thread.Status()
  • returns string
• thread.Stopped - It is suggested that if you have code that loops you also check this to make sure the code end cleanly.
  • returns bool
• thread.Disable() - Disables the thread completely
  • returns nothing

HTTP

• http.Get(url)
  • returns {body:'',headers:[], status: 200}
• http.Post(url, body)
  • returns {body:'',headers:[], status: 200}
• http.PostForm(url, bodyObject)
  • returns {body:'',headers:[], status: 200}
• http.Put(url, body)
  • returns {body:'',headers:[], status: 200}
• http.Head(url)
  • returns {headers:[], status: 200}
• http.Delete(url)
  • returns {body:'',headers:[], status: 200}

Redis

• redis.Do(method, args....)
  • return [response from redis, error (if one)]

Response

• response.Write(value)
  • Used when a wart is in endpoint mode. Writes to the response body of an http request.
  • returns nothing.
• response.Error(errorString, statusCode)
  • Used when a wart is in endpoint mode. Writes an error in response to the endpoint.
  • returns nothing.
• response.SetContentType(type)
  • Used when a wart is in endpoint mode. Sets the content type header.
  • returns nothing.
• response.SetHeader(key,value)
  • Used when a wart is in endpoint mode. Sets the header specfied in key to the value.
  • returns nothing.

Request

• request.Method
  • returns string
• request.Path
  • returns string
• request.Query
  • returns {:[values]}
• request.Body
  • returns string
• request.GetHeader(key)
  • Used when a wart is in endpoint mode. Gets value from header.
  • returns value.

SQL

• sql.New(connectionString, driverType)
  • supported driver types: mysql
  • returns db interface
• db.Ping()
  • returns an error if it fails to ping the db
• db.Query(query, arguments...)
  • returns rows or nil if error
• db.Exec(query, arguments...)
  • returns number of impacted rows or undefined if error
• db.Close()
  • returns error if any

Wart Todo

• - Run a thread from redis.
• - Create thread from file.
• - Stop thread if wart is unhealthy.
• - Stop thread if status is disabled.
• - Stop thread if not the owner of thread.
• - CPU health check based on threshold.
• - Memory health check based on threshold.
• - Recover from critical state when thresholds are met.

Javascript Todo

• - Basic javascript implementation
• - Keep scope inside of thread
• - Redis wrapper
• - Http wrapper
• - Wart information i.e. Health, name, cluster
• - Thread information i.e. Delay, State, Status
• - Thread control i.e. Stop thread, disable thread.