Technologies and design patterns of Erlang/OTP have been proven over the years. Now in Golang. Up to x5 times faster than original Erlang/OTP in terms of network messaging. The easiest way to create an OTP-designed application in Golang.

Purpose

The goal of this project is to leverage Erlang/OTP experience with Golang performance. Ergo Framework implements DIST protocol, ETF data format and OTP design patterns gen.Server, gen.Supervisor, gen.Application which makes you able to create distributed, high performance and reliable microservice solutions having native integration with Erlang infrastructure

Features

Support Erlang 24 (including Alias and Remote Spawn features)
Spawn Erlang-like processes
Register/unregister processes with simple atom
gen.Server behavior support (with atomic state)
gen.Supervisor behavior support with all known restart strategies support
- One For One
- One For All
- Rest For One
- Simple One For One
gen.Application behavior support with all known starting types support
- Permanent
- Temporary
- Transient
gen.Stage behavior support (originated from Elixir's GenStage). This is abstraction built on top of gen.Server to provide a simple way to create a distributed Producer/Consumer architecture, while automatically managing the concept of backpressure. This implementation is fully compatible with Elixir's GenStage. Example is here examples/genstage or just run go run ./examples/genstage to see it in action
gen.Saga behavior support. It implements Saga design pattern - a sequence of transactions that updates each service state and publishes the result (or cancels the transaction or triggers the next transaction step). gen.Saga also provides a feature of interim results (can be used as transaction progress or as a part of pipeline processing), time deadline (to limit transaction lifespan), two-phase commit (to make distributed transaction atomic). Here is example examples/gensaga.
gen.Raft behavior support. It's improved implementation of Raft consensus algorithm. The key improvement is using quorum under the hood to manage the leader election process and make the Raft cluster more reliable. This implementation supports quorums of 3, 5, 7, 9, or 11 quorum members. Here is an example of this feature examples/raft.
Connect to (accept connection from) any Erlang/Elixir node within a cluster
Making sync request ServerProcess.Call, async - ServerProcess.Cast or Process.Send in fashion of gen_server:call, gen_server:cast, erlang:send accordingly
Monitor processes/nodes, local/remote
Link processes local/remote
RPC callbacks support
embedded EPMD (in order to get rid of erlang' dependencies)
Unmarshalling terms into the struct using etf.TermIntoStruct, etf.TermProplistIntoStruct or to the string using etf.TermToString
Custom marshaling/unmarshaling via Marshal and Unmarshal interfaces
Encryption (TLS 1.3) support (including autogenerating self-signed certificates)
Compression support (with customization of compression level and threshold). It can be configured for the node or a particular process.
Proxy support with end-to-end encryption, includeing compression/fragmentation/linking/monitoring features.
Tested and confirmed support Windows, Darwin (MacOS), Linux, FreeBSD.
Zero dependencies. All features are implemented using the standard Golang library.

Requirements

Go 1.17.x and above

Versioning

Golang introduced v2 rule a while ago to solve complicated dependency issues. We found this solution very controversial and there is still a lot of discussion around it. So, we decided to keep the old way for the versioning, but have to use the git tag with v1 as a major version (due to "v2 rule" restrictions). Since now we use git tag pattern 1.999.XYZ where X - major number, Y - minor, Z - patch version.

Changelog

Here are the changes of latest release. For more details see the ChangeLog

v2.1.0 2022-04-19 [tag version v1.999.210]

Introduced compression feature support. Here are new methods and options to manage this feature:
- gen.Process:
  - SetCompression(enable bool), Compression() bool
  - SetCompressionLevel(level int) bool, CompressionLevel() int
  - SetCompressionThreshold(threshold int) bool, CompressionThreshold() int messages smaller than the threshold will be sent with no compression. The default compression threshold is 1024 bytes.
- node.Options:
  - Compression these settings are used as defaults for the spawning processes
- this feature will be ignored if the receiver is running on either the Erlang or Elixir node
Introduced proxy feature support with end-to-end encryption.
- node.Node new methods:
  - AddProxyRoute(...), RemoveProxyRoute(...)
  - ProxyRoute(...), ProxyRoutes()
  - NodesIndirect() returns list of connected nodes via proxy connection
- node.Options:
  - Proxy for configuring proxy settings
- includes support (over the proxy connection): compression, fragmentation, link/monitor process, monitor node
- example examples/proxy.
- this feature is not available for the Erlang/Elixir nodes
Introduced behavior gen.Raft. It's improved implementation of Raft consensus algorithm. The key improvement is using quorum under the hood to manage the leader election process and make the Raft cluster more reliable. This implementation supports quorums of 3, 5, 7, 9, or 11 quorum members. Here is an example of this feature examples/raft.
Introduced interfaces to customize network layer
- Resolver to replace EPMD routines with your solution (e.g., ZooKeeper or any other service registrar)
- Handshake allows customizing authorization/authentication process
- Proto provides the way to implement proprietary protocols (e.g., IoT area)
Other new features:
- gen.Process new methods:
  - NodeUptime(), NodeName(), NodeStop()
- gen.ServerProcess new method:
  - MessageCounter() shows how many messages have been handled by the gen.Server callbacks
- gen.ProcessOptions new option:
  - ProcessFallback allows forward messages to the fallback process if the process mailbox is full. Forwarded messages are wrapped into gen.MessageFallback struct. Related to issue #96.
- gen.SupervisorChildSpec and gen.ApplicationChildSpec got option gen.ProcessOptions to customize options for the spawning child processes.
Improved sending messages by etf.Pid or etf.Alias: methods gen.Process.Send, gen.ServerProcess.Cast, gen.ServerProcess.Call now return node.ErrProcessIncarnation if a message is sending to the remote process of the previous incarnation (remote node has been restarted). Making monitor on a remote process of the previous incarnation triggers sending gen.MessageDown with reason incarnation.
Introduced type gen.EnvKey for the environment variables
All spawned processes now have the node.EnvKeyNode variable to get access to the node.Node value.
Improved performance of local messaging (up to 8 times for some cases)
Important node.Options has changed. Make sure to adjust your code.
Fixed issue #89 (incorrect handling of Call requests)
Fixed issues #87, #88 and #93 (closing network socket)
Fixed issue #96 (silently drops message if process mailbox is full)
Updated minimal requirement of Golang version to 1.17 (go.mod)
We still keep the rule Zero Dependencies

Benchmarks

Here is simple EndToEnd test demonstrates performance of messaging subsystem

Hardware: workstation with AMD Ryzen Threadripper 3970X (64) @ 3.700GHz

❯❯❯❯ go test -bench=NodeParallel -run=XXX -benchtime=10s
goos: linux
goarch: amd64
pkg: github.com/ergo-services/ergo/tests
cpu: AMD Ryzen Threadripper 3970X 32-Core Processor
BenchmarkNodeParallel-64                 4738918              2532 ns/op
BenchmarkNodeParallelSingleNode-64      100000000              429.8 ns/op

PASS
ok      github.com/ergo-services/ergo/tests  29.596s

these numbers show almost 500.000 sync requests per second for the network messaging via localhost and 10.000.000 sync requests per second for the local messaging (within a node).

Compression

This benchmark shows the performance of compression for sending 1MB message between two nodes (via a network).

❯❯❯❯ go test -bench=NodeCompression -run=XXX -benchtime=10s
goos: linux
goarch: amd64
pkg: github.com/ergo-services/ergo/tests
cpu: AMD Ryzen Threadripper 3970X 32-Core Processor
BenchmarkNodeCompressionDisabled1MBempty-64         2400           4957483 ns/op
BenchmarkNodeCompressionEnabled1MBempty-64          5769           2088051 ns/op
BenchmarkNodeCompressionEnabled1MBstring-64         5202           2077099 ns/op
PASS
ok      github.com/ergo-services/ergo/tests     56.708s

It demonstrates more than 2 times improvement.

Proxy

This benchmark demonstrates how proxy feature and e2e encryption impact a messaging performance.

❯❯❯❯ go test -bench=NodeProxy -run=XXX -benchtime=10s
goos: linux
goarch: amd64
pkg: github.com/ergo-services/ergo/tests
cpu: AMD Ryzen Threadripper 3970X 32-Core Processor
BenchmarkNodeProxy_NodeA_to_NodeC_direct_Message_1KB-64                     1908477       6337 ns/op
BenchmarkNodeProxy_NodeA_to_NodeC_via_NodeB_Message_1KB-64                  1700984       7062 ns/op
BenchmarkNodeProxy_NodeA_to_NodeC_via_NodeB_Message_1KB_Encrypted-64        1271125       9410 ns/op
PASS
ok      github.com/ergo-services/ergo/tests     45.649s

Ergo Framework vs original Erlang/OTP

Hardware: laptop with Intel(R) Core(TM) i5-8265U (4 cores. 8 with HT)

benchmarks

sources of these benchmarks are here

EPMD

Ergo Framework has embedded EPMD implementation in order to run your node without external epmd process needs. By default, it works as a client with erlang' epmd daemon or others ergo's nodes either.

The one thing that makes embedded EPMD different is the behavior of handling connection hangs - if ergo' node is running as an EPMD client and lost connection, it tries either to run its own embedded EPMD service or to restore the lost connection.

Observer

It's a standard Erlang tool. Observer is a graphical tool for observing the characteristics of Erlang systems. The tool Observer displays system information, application supervisor trees, process information.

Here you can see this feature in action using one of the examples:

observer demo

Examples

Code below is a simple implementation of gen.Server pattern examples/simple

package main

import (
	"fmt"
	"time"

	"github.com/ergo-services/ergo"
	"github.com/ergo-services/ergo/etf"
	"github.com/ergo-services/ergo/gen"
	"github.com/ergo-services/ergo/node"
)

// simple implementation of Server
type simple struct {
	gen.Server
}

func (s *simple) HandleInfo(process *gen.ServerProcess, message etf.Term) gen.ServerStatus {
	value := message.(int)
	fmt.Printf("HandleInfo: %#v \n", message)
	if value > 104 {
		return gen.ServerStatusStop
	}
	// sending message with delay
	process.SendAfter(process.Self(), value+1, time.Duration(1*time.Second))
	return gen.ServerStatusOK
}

func main() {
	// create a new node
	node, _ := ergo.StartNode("[email protected]", "cookies", node.Options{})

	// spawn a new process of gen.Server
	process, _ := node.Spawn("gs1", gen.ProcessOptions{}, &simple{})

	// send a message to itself
	process.Send(process.Self(), 100)

	// wait for the process termination.
	process.Wait()
	fmt.Println("exited")
	node.Stop()
}

here is output of this code

$ go run ./examples/simple
HandleInfo: 100
HandleInfo: 101
HandleInfo: 102
HandleInfo: 103
HandleInfo: 104
HandleInfo: 105
exited

See examples/ for more details

Elixir Phoenix Users

Users of the Elixir Phoenix framework might encounter timeouts when trying to connect a Phoenix node to an ergo node. The reason is that, in addition to global_name_server and net_kernel, Phoenix attempts to broadcast messages to the pg2 PubSub handler

To work with Phoenix nodes, you must create and register a dedicated pg2 GenServer, and spawn it inside your node. The spawning process must have "pg2" as a process name:

type Pg2GenServer struct {
    gen.Server
}

func main() {
    // ...
    pg2 := &Pg2GenServer{}
    node1, _ := ergo.StartNode("[email protected]", "cookies", node.Options{})
    process, _ := node1.Spawn("pg2", gen.ProcessOptions{}, pg2, nil)
    // ...
}

Development and debugging

There are options already defined that you might want to use

-ergo.trace - enable extended debug info
-ergo.norecover - disable panic catching
-ergo.warning - enable/disable warnings (default: enable)

To enable Golang profiler just add --tags debug in your go run or go build like this:

go run --tags debug ./examples/genserver/demoGenServer.go

Now golang' profiler is available at http://localhost:9009/debug/pprof

To check test coverage:

go test -coverprofile=cover.out ./...
go tool cover -html=cover.out -o coverage.html

To run tests with cleaned test cache:

go vet
go clean -testcache
go test -v ./...

To run benchmarks:

go test -bench=Node -run=X -benchmem

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Commercial support

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