Hippo

A Microservices Toolkit.

Hippo is a collection of well crafted go packages that help you build robust, reliable, maintainable microservices. It is not a full-fledged framework with lot of magic, predefined architecture, specific patterns and bullshit opinions so you will be the one behind the wheel.

It provides libraries to implement components for service discovery, async jobs, authentication, authorization, logging, caching, metrics, tracing, rate-limiting...etc which are essential requirements for running microservices in production.

Documentation

Installation:

go get -u github.com/clivern/hippo

import (
    "github.com/clivern/hippo"
)

Components:

HTTP Requests Component

httpClient := hippo.NewHTTPClient()

// Get Request
response, err := httpClient.Get(
    "https://httpbin.org/get",
    map[string]string{"url_arg_key": "url_arg_value"},
    map[string]string{"header_key": "header_value"},
)

// Delete Request
response, err := httpClient.Delete(
    "https://httpbin.org/delete",
    map[string]string{"url_arg_key": "url_arg_value"},
    map[string]string{"header_key": "header_value"},
)

// Post Request
response, err := httpClient.Post(
    "https://httpbin.org/post",
    `{"RequestBodyKey":"RequestBodyValue"}`,
    map[string]string{"url_arg_key": "url_arg_value"},
    map[string]string{"header_key": "header_value"},
)

// Put Request
response, err := httpClient.Put(
    "https://httpbin.org/put",
    `{"RequestBodyKey":"RequestBodyValue"}`,
    map[string]string{"url_arg_key": "url_arg_value"},
    map[string]string{"header_key": "header_value"},
)

// ....

statusCode := httpClient.GetStatusCode(response)
responseBody, err := httpClient.ToString(response)

Cache/Redis Component

driver := hippo.NewRedisDriver("localhost:6379", "password", 0)

// connect to redis server
ok, err := driver.Connect()
// ping check
ok, err = driver.Ping()

// set an item
ok, err = driver.Set("app_name", "Hippo", 0)
// check if exists
ok, err = driver.Exists("app_name")
// get value
value, err := driver.Get("app_name")
// delete an item
count, err := driver.Del("app_name")

// hash set
ok, err = driver.HSet("configs", "app_name", "Hippo")
// check if item on a hash
ok, err = driver.HExists("configs", "app_name")
// get item from a hash
value, err = driver.HGet("configs", "app_name")
// hash length
count, err = driver.HLen("configs")
// delete item from a hash
count, err = driver.HDel("configs", "app_name")
// clear the hash
count, err = driver.HTruncate("configs")

// Pub/Sub
driver.Publish("hippo", "Hello")
driver.Subscribe("hippo", func(message hippo.Message) error {
    // message.Channel
    // message.Payload
    return nil
})

Time Series/Graphite Component

import "time"


metric := hippo.NewMetric("hippo1.up", "23", time.Now().Unix()) // Type is hippo.Metric

metrics := hippo.NewMetrics("hippo2.up", "35", time.Now().Unix()) // type is []hippo.Metric
metrics = append(metrics, hippo.NewMetric("hippo2.down", "40", time.Now().Unix()))
metrics = append(metrics, hippo.NewMetric("hippo2.error", "70", time.Now().Unix()))

// NewGraphite(protocol string, host string, port int, prefix string)
// protocol can be tcp, udp or nop
// prefix is a metric prefix
graphite := hippo.NewGraphite("tcp", "127.0.0.1", 2003, "")
error := graphite.Connect()

if error == nil{
    // send one by one
    graphite.SendMetric(metric)

    // bulk send
    graphite.SendMetrics(metrics)
}

System Stats Component

// func NewSystemStats(enableCPU, enableMem, enableGC bool) *SystemStats {
stats := hippo.NewSystemStats(true, true, true)
stats.GetStats() // type map[string]uint64
// map[cpu.cgo_calls:0 cpu.goroutines:1 mem.alloc:0....]

Correlation ID Component

correlation := hippo.NewCorrelation()
correlation.UUIDv4()

Workers Pool Component

import "fmt"

tasks := []*hippo.Task{
    hippo.NewTask(func() (string, error) {
        fmt.Println("Task #1")
        return "Result 1", nil
    }),
    hippo.NewTask(func() (string, error) {
        fmt.Println("Task #2")
        return "Result 2", nil
    }),
    hippo.NewTask(func() (string, error) {
        fmt.Println("Task #3")
        return "Result 3", nil
    }),
}

// hippo.NewWorkersPool(tasks []*Task, concurrency int) *WorkersPool
p := hippo.NewWorkersPool(tasks, 2)
p.Run()

var numErrors int
for _, task := range p.Tasks {
    if task.Err != nil {
        fmt.Println(task.Err)
        numErrors++
    } else {
        fmt.Println(task.Result)
    }
    if numErrors >= 10 {
        fmt.Println("Too many errors.")
        break
    }
}

Health Checker Component

import "fmt"

healthChecker := hippo.NewHealthChecker()
healthChecker.AddCheck("ping_check", func() (bool, error){
    return true, nil
})
healthChecker.AddCheck("db_check", func() (bool, error){
    return false, fmt.Errorf("Database Down")
})
healthChecker.RunChecks()

fmt.Println(healthChecker.ChecksStatus())
// Output -> DOWN
fmt.Println(healthChecker.ChecksReport())
// Output -> [{"id":"ping_check","status":"UP","error":"","result":true},{"id":"db_check","status":"DOWN","error":"Database Down","result":false}] <nil>

import "fmt"

healthChecker := hippo.NewHealthChecker()

healthChecker.AddCheck("url_check", func() (bool, error){
    return hippo.HTTPCheck("httpbin_service", "https://httpbin.org/status/503", map[string]string{}, map[string]string{})
})
healthChecker.AddCheck("redis_check", func() (bool, error){
    return hippo.RedisCheck("redis_service", "localhost:6379", "", 0)
})
healthChecker.RunChecks()

fmt.Println(healthChecker.ChecksStatus())
// Outputs -> DOWN
fmt.Println(healthChecker.ChecksReport())
// Outputs -> [{"id":"url_check","status":"DOWN","error":"Service httpbin_service is unavailable","result":false},{"id":"redis_check","status":"DOWN","error":"Error while connecting redis_service: dial tcp [::1]:6379: connect: connection refused","result":false}] <nil>

API Rate Limiting

import "time"

// Create a limiter with a specific identifier(IP address or access token or username....etc)
// NewCallerLimiter(identifier string, eventsRate rate.Limit, tokenBurst int) *rate.Limiter
limiter := hippo.NewCallerLimiter("10.10.10.10", 100, 1)
if limiter.Allow() == false {
    // Don't allow access
} else {
    // Allow Access
}


// auto clean old clients (should run as background process)
// CleanupCallers(cleanAfter time.Duration)
go func(){
    for {
        time.Sleep(60 * time.Second)
        hippo.CleanupCallers(60)
    }
}()

Logger Component

logger, _ := hippo.NewLogger("debug", "json", []string{"stdout", "/var/log/error.log"})

logger.Info("Hello World!")
logger.Debug("Hello World!")
logger.Warn("Hello World!")
logger.Error("Hello World!")

defer logger.Sync()

// check if path exists
exists := hippo.PathExists("/var/log")

// check if file exists
exists := hippo.FileExists("/var/log/error.log")

// check if dir exists
exists := hippo.DirExists("/var/log")

// ensure that dir exists
exists, err := hippo.EnsureDir("/var/log", 755)

Latency Tracker Component

httpClient := hippo.NewHTTPClient()

latency := hippo.NewLatencyTracker()
latency.NewAction("api.call")

// First HTTP Call
start := time.Now()
httpClient.Get(
    "https://httpbin.org/get",
    map[string]string{},
    map[string]string{},
)
latency.SetPoint("api.call", start, time.Now())

// Another HTTP Call
latency.SetStart("api.call", time.Now())
httpClient.Get(
    "https://httpbin.org/get",
    map[string]string{},
    map[string]string{},
)
latency.SetEnd("api.call", time.Now())

// Now it will calculate the average
fmt.Println(latency.GetLatency("api.call"))
// Output 486.217112ms <nil>

Versioning

For transparency into our release cycle and in striving to maintain backward compatibility, Hippo is maintained under the Semantic Versioning guidelines and release process is predictable and business-friendly.

See the Releases section of our GitHub project for changelogs for each release version of Hippo. It contains summaries of the most noteworthy changes made in each release.

Bug tracker

If you have any suggestions, bug reports, or annoyances please report them to our issue tracker at https://github.com/clivern/hippo/issues

Security Issues

If you discover a security vulnerability within Hippo, please send an email to hello@clivern.com

Contributing

We are an open source, community-driven project so please feel free to join us. see the contributing guidelines for more details.

License

© 2019, Clivern. Released under MIT License.

Hippo is authored and maintained by @Clivern.