README
¶
faas
An easy way to develop event-driven functions with modular approach using dependency injection.
The faas lets you write lightweight functions that run in different environments, including:
- Your local development machine
- AWS Lambda Functions
- Knative Eventing
History
This project started when we needed to use the lambda and it connected in several queues (sns, sqs, kinesis), and the format of the messages that arrived from the messenger was different in each technology.
So we created a way to convert all messages to the cloudevents format (cloudevents.io) and receive this message in the handler.
But we had a problem with testing our functions in a development environment, so in addition to our handler being a lambda, it should be a listener for nats (nats.io).
Shortly thereafter, we started looking at knative eventing (knative.dev), so we grew the project to support knative eventing as well.
And a little while ago we needed to create workers to connect to kafka and we added them too.
In short, it's a way for you to run your function in many different environments. it could be a lambda, it could be a knative, it could be a listener for kafka and nats, but we made it pretty plug and play, so in the future we could, for example, support rabbitmq as well.
All you need is to write your handler in a single format and configure what your handler will support, you can create supporting all and use the FAAS_CMD_DEFAULT config to specify which is the default implementation.
Installation
go get -u github.com/americanas-go/faas
Example
package main
import (
"context"
"os"
"github.com/americanas-go/config"
"github.com/americanas-go/faas/cloudevents"
"github.com/americanas-go/faas/cloudevents/plugins/contrib/americanas-go/log.v1"
"github.com/americanas-go/faas/cmd"
ilog "github.com/americanas-go/ignite/americanas-go/log.v1"
igce "github.com/americanas-go/ignite/cloudevents/sdk-go.v2"
v2 "github.com/cloudevents/sdk-go/v2"
"go.uber.org/fx"
)
func main() {
config.Load()
ilog.New()
options := fx.Options(
fx.Provide(
func() igce.Handler {
return Handle
},
func() []cloudevents.Middleware {
return []cloudevents.Middleware{
log.NewLogger(),
}
},
),
)
// sets env var
os.Setenv("FAAS_CMD_DEFAULT", "nats")
// os.Setenv("FAAS_CMD_DEFAULT", "cloudevents")
// os.Setenv("FAAS_CMD_DEFAULT", "lambda")
// go run main.go help
err := cmd.Run(options,
// go run main.go nats
// or
// FAAS_CMD_DEFAULT=nats go run main.go
cmd.NewNats(),
// go run main.go cloudevents
// or
// FAAS_CMD_DEFAULT=cloudevents go run main.go
cmd.NewCloudEvents(),
// go run main.go lambda
// or
// FAAS_CMD_DEFAULT=lambda go run main.go
cmd.NewLambda(),
)
if err != nil {
panic(err)
}
}
func Handle(ctx context.Context, in v2.Event) (*v2.Event, error) {
e := v2.NewEvent()
e.SetID("changeme")
e.SetSubject("changeme")
e.SetSource("changeme")
e.SetType("changeme")
e.SetExtension("partitionkey", "changeme")
err := e.SetData(v2.TextPlain, "changeme")
return &e, err
}
Example of nats client
package main
import (
"context"
"io/ioutil"
"github.com/americanas-go/config"
iglog "github.com/americanas-go/ignite/americanas-go/log.v1"
ignats "github.com/americanas-go/ignite/nats-io/nats.go.v1"
"github.com/americanas-go/log"
"github.com/nats-io/nats.go"
)
func main() {
config.Load()
iglog.New()
var err error
var conn *nats.Conn
conn, err = ignats.NewConn(context.Background())
if err != nil {
log.Fatal(err)
}
defer conn.Close()
subject := "changeme"
var b []byte
b, err = ioutil.ReadFile("examples/simple/client/example-nats.json")
if err != nil {
log.Fatal(err)
}
msg := &nats.Msg{
Subject: subject,
Data: b,
}
err = conn.PublishMsg(msg)
if err != nil {
log.Fatal(err)
}
log.Infof("published group message on subject [%s]", subject)
}
Example of sns client
package main
import (
"context"
"encoding/json"
"io/ioutil"
"github.com/americanas-go/config"
iglog "github.com/americanas-go/ignite/americanas-go/log.v1"
igaws "github.com/americanas-go/ignite/aws/aws-sdk-go.v2"
"github.com/americanas-go/log"
"github.com/aws/aws-sdk-go-v2/credentials"
"github.com/aws/aws-sdk-go-v2/service/sns"
"github.com/aws/aws-sdk-go/aws"
)
type Message struct {
Default string `json:"default"`
}
func main() {
config.Load()
iglog.New()
var err error
ctx := context.Background()
awsConfig := igaws.NewConfig(ctx)
// if you have already set aws credentials in your system environment variables,
// ignore the two lines below
awsConfig.Region = "YOUR_AWS_REGION"
awsConfig.Credentials = credentials.
NewStaticCredentialsProvider("YOUR_AWS_ACCESS_KEY_ID", "YOUR_AWS_SECRET_ACCESS_KEY", "")
client := sns.NewFromConfig(awsConfig)
topic := "arn:aws:sns:us-east-1:000000000000:changeme"
var b []byte
b, err = ioutil.ReadFile("examples/simple/client/example-sns.json")
if err != nil {
log.Fatal(err)
}
msg := Message{
Default: string(b),
}
msgBytes, _ := json.Marshal(msg)
msgStr := string(msgBytes)
res, err := client.Publish(ctx, &sns.PublishInput{
Message: aws.String(msgStr),
MessageStructure: aws.String("json"),
TopicArn: aws.String(topic),
})
if err != nil {
log.Fatal(err)
}
log.Infof("published group message on topic [%s]", topic)
resJSON, _ := json.Marshal(res)
log.Info(string(resJSON))
}
Contributing
Every help is always welcome. Feel free do throw us a pull request, we'll do our best to check it out as soon as possible. But before that, let us establish some guidelines:
- This is an open source project so please do not add any proprietary code or infringe any copyright of any sort.
- Avoid unnecessary dependencies or messing up go.mod file.
- Be aware of golang coding style. Use a lint to help you out.
- Add tests to cover your contribution.
- Add godoc to your code.
- Use meaningful messages to your commits.
- Use pull requests.
- At last, but also important, be kind and polite with the community.
Any submitted issue which disrespect one or more guidelines above, will be discarded and closed.
Released under the MIT License.
Directories