Teal.Finance/Server
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Opinionated boilerplate HTTP server with CORS, OPA, Prometheus, rate-limiter… for API and static website. |
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Origin
This library was originally developed as part of the project Rainbow during hackathons, based on older Teal.Finance products, and then moved to its own repository.
Features
Teal.Finance/Server supports:
- Metrics server exporting data to Prometheus or other monitoring services ;
- File server intended for static web files ;
- HTTP/REST server for API endpoints (compatible any Go-standard HTTP handlers) ;
- Chained middlewares (fork of github.com/justinas/alice)
- Auto-completed error response in JSON format ;
- Middleware: authentication rules based on Datalog/Rego files using Open Policy Agent ;
- Middleware: rate limiter to prevent flooding by incoming requests ;
- Middleware: logging of incoming requests ;
- Middleware: Cross-Origin Resource Sharing (CORS).
License
LGPL-3.0-or-later: GNU Lesser General Public License v3.0 or later (tl;drLegal, Choosealicense.com). See the LICENSE file.
Except the two example files under CC0-1.0 (Creative Commons Zero v1.0 Universal) and the file chain.go (fork) under the MIT License.
High-level usage
See the high-level example.
The following Go code uses the high-level function Server.RunServer().
package main
import (
"log"
"github.com/teal-finance/server"
)
func main() {
s := server.Server{
Version: "MyApp-1.2.3",
Resp: "https://my-dns.com/doc",
AllowedOrigins: []string{"http://my-dns.com"},
OPAFilenames: []string{"example-auth.rego"},
}
h := myHandler()
// main port 8080, export port 9093, rate limiter 10 20, debug mode
log.Fatal(s.RunServer(h, 8080, 9093, 10, 20, true))
}
Low-level example
See the low-level example.
See also a complete real example in the repo github.com/teal-finance/rainbow.
The following Go code can be replaced by the high-level function Server.RunServer() presented in the previous chapter. The following Go code is intended to show that the Teal.Finance/Server can be customized to meet specific requirements.
0. // The metrics server is for use with Prometheus or another compatible monitoring tool. metrics := export.Metrics{} middlewares, connState = metrics.StartServer(9093, true) // Limit the input request rate per IP reqLimiter := limiter.New(10, 20, true, resErr) middlewares = middlewares.Append() // Endpoint authentication rules (Open Policy Agent) policy, err := opa.New(resErr, []string{"example-auth.rego"}) if err != nil { log.Fatal(err) } // CORS allowedOrigins := []string{"http://my-dns.com"} middlewares = middlewares.Append( server.LogRequests, reqLimiter.Limit, server.Header("MyServerName-1.2.3"), policy.Auth, cors.HandleCORS(allowedOrigins), ) return middlewares, connState } // runServer runs in foreground the main server. func runServer(h http.Handler, connState func(net.Conn, http.ConnState)) { server := http.Server{ Addr: ":8080", Handler: h, TLSConfig: nil, ReadTimeout: 1 * time.Second, ReadHeaderTimeout: 1 * time.Second, WriteTimeout: 1 * time.Second, IdleTimeout: 1 * time.Second, MaxHeaderBytes: 222, TLSNextProto: nil, ConnState: connState, ErrorLog: log.Default(), BaseContext: nil, ConnContext: nil, } log.Print("Server listening on http://localhost", server.Addr) log.Fatal(server.ListenAndServe()) } ">
package main import ( "log" "net" "net/http" "time" "github.com/teal-finance/server" "github.com/teal-finance/server/chain" "github.com/teal-finance/server/cors" "github.com/teal-finance/server/export" "github.com/teal-finance/server/limiter" "github.com/teal-finance/server/opa" "github.com/teal-finance/server/reserr" ) func main() { middlewares, connState := setMiddlewares() h := myHandler() h = middlewares.Then(h) runServer(h, connState) } func setMiddlewares() (middlewares chain.Chain, connState func(net.Conn, http.ConnState)) { // Uniformize error responses with API doc resErr := reserr.New("https://my-dns.com/doc") // Start a metrics server in background if export port > 0. // The metrics server is for use with Prometheus or another compatible monitoring tool. metrics := export.Metrics{} middlewares, connState = metrics.StartServer(9093, true) // Limit the input request rate per IP reqLimiter := limiter.New(10, 20, true, resErr) middlewares = middlewares.Append() // Endpoint authentication rules (Open Policy Agent) policy, err := opa.New(resErr, []string{"example-auth.rego"}) if err != nil { log.Fatal(err) } // CORS allowedOrigins := []string{"http://my-dns.com"} middlewares = middlewares.Append( server.LogRequests, reqLimiter.Limit, server.Header("MyServerName-1.2.3"), policy.Auth, cors.HandleCORS(allowedOrigins), ) return middlewares, connState } // runServer runs in foreground the main server. func runServer(h http.Handler, connState func(net.Conn, http.ConnState)) { server := http.Server{ Addr: ":8080", Handler: h, TLSConfig: nil, ReadTimeout: 1 * time.Second, ReadHeaderTimeout: 1 * time.Second, WriteTimeout: 1 * time.Second, IdleTimeout: 1 * time.Second, MaxHeaderBytes: 222, TLSNextProto: nil, ConnState: connState, ErrorLog: log.Default(), BaseContext: nil, ConnContext: nil, } log.Print("Server listening on http://localhost", server.Addr) log.Fatal(server.ListenAndServe()) }
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