fix program arguments not being passed to commands

.gitignore

@@ -0,0 +1,2 @@
+gohookr
+test_output

Dockerfile

@@ -0,0 +1,9 @@
+FROM golang:1.16
+
+WORKDIR /go/src/app
+COPY . .
+
+RUN go get -d -v ./...
+RUN go install -v ./...
+
+CMD ["gohookr"]

Makefile

@@ -0,0 +1,20 @@
+all: install
+
+clean:
+	rm -rf gohookr
+
+build:
+	go mod tidy
+	go build -o gohookr
+
+install: build
+	cp gohookr /usr/local/bin/
+	cp gohookr.service /usr/lib/systemd/system/
+	cp -n config.json /etc/gohookr.json
+	systemctl daemon-reload
+	systemctl enable --now gohookr
+
+uninstall:
+	systemctl disable --now gohookr
+	rm -rf /usr/local/bin/gohookr /usr/lib/systemd/system/gohookr.service
+	systemctl daemon-reload

config.json

@@ -1,9 +1,34 @@
 {
+  "ListenAddress": "127.0.0.1:8654",
   "Services": {
     "test": {
-      "Script": "./example.sh",
-      "Secret": "THISISVERYSECRET",
-      "SignatureHeader": "X-Gitea-Signature"
+      "Script": {
+          "Program": "./example.sh",
+          "AppendPayload": true,
+          "AppendHeaders": true
+      },
+      "DisableSignatureVerification": true,
+      "Tests": [
+        {
+          "Program": "echo",
+          "Arguments": [ "test" ]
+        }
+      ]
+    },
+    "fails_tests": {
+      "Script": {
+          "Program": "./example.sh",
+          "AppendPayload": true
+      },
+      "Secret": "who_cares",
+      "SignatureHeader": "X-Hub-Signature-256",
+      "SignaturePrefix": "sha256=",
+      "Tests": [
+        {
+          "Program": "false",
+          "Arguments": []
+        }
+      ]
     }
   }
 }

config/command.go

@@ -0,0 +1,41 @@
+package config
+
+import (
+	"fmt"
+	"net/http"
+	"os/exec"
+	"strings"
+)
+
+type Command struct {
+	Program       string
+	Arguments     []string
+	AppendPayload bool
+	AppendHeaders bool
+}
+
+func (c Command) Execute(payload string, header http.Header) ([]byte, error) {
+	arguments := make([]string, len(c.Arguments))
+	copy(arguments, c.Arguments)
+
+	if c.AppendPayload {
+		arguments = append(arguments, payload)
+	}
+
+	if c.AppendHeaders {
+		var header_builder strings.Builder;
+		header.Write(&header_builder);
+
+		arguments = append(arguments, header_builder.String())
+	}
+
+	return exec.Command(c.Program, arguments...).Output()
+}
+
+func (c Command) String() string {
+	return fmt.Sprintf(
+		"<Command cmd=%v AppendPayload=%v>",
+		append([]string{c.Program}, c.Arguments...),
+		c.AppendPayload,
+	)
+}

config/config.go

@@ -0,0 +1,35 @@
+package config
+
+// The struct that represents the config.json file
+type Config struct {
+	ListenAddress string
+	Services      map[string]struct {
+		Script                       Command
+		Secret                       string
+		SignaturePrefix              string
+		SignatureHeader              string
+		DisableSignatureVerification bool
+		Tests                        []Command
+	}
+}
+
+// Check that all required fields are filled in
+func (c Config) Validate() error {
+	if c.ListenAddress == "" {
+		return requiredFieldError{"ListenAddress", ""}
+	}
+
+	for serviceName, service := range c.Services {
+		if service.Script.Program == "" {
+			return requiredFieldError{"Script.Program", serviceName}
+		}
+		if !service.DisableSignatureVerification && service.SignatureHeader == "" {
+			return requiredFieldError{"SignatureHeader", serviceName}
+		}
+		if !service.DisableSignatureVerification && service.Secret == "" {
+			return requiredFieldError{"Secret", serviceName}
+		}
+	}
+
+	return nil
+}

config/errors.go

@@ -0,0 +1,12 @@
+package config
+
+import "fmt"
+
+type requiredFieldError struct {
+	fieldName   string
+	serviceName string
+}
+
+func (e requiredFieldError) Error() string {
+	return fmt.Sprintf("%v cannot be empty (%v)", e.fieldName, e.serviceName)
+}

example.sh

@@ -1,2 +1,3 @@
 #!/usr/bin/bash
 date >> test_output
+echo "$1" "$2" >> test_output

go.mod

@@ -1,4 +1,4 @@
-module git.alra.uk/alvierahman90/ghookr
+module git.alv.cx/alvierahman90/gohookr
 
 go 1.16
 

gohookr.service

@@ -0,0 +1,11 @@
+[Unit]
+Description=A really simple webhook receiver.
+After=network.target
+
+[Service]
+Restart=on-failure
+RestartSec=5s
+ExecStart=/usr/local/bin/gohookr
+
+[Install]
+WantedBy=multi-user.target

main.go

@@ -7,86 +7,101 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"log"
 	"net/http"
 	"os"
-	"os/exec"
 
+	"git.alv.cx/alvierahman90/gohookr/config"
 	"github.com/gorilla/mux"
 )
 
-var config_filename = "/etc/ghookr.json"
+var config_filename = "/etc/gohookr.json"
+var checkSignature = true
+var c config.Config
 
 func main() {
-	// Used for testing purposes... generates hmac string
-	if os.Getenv("HMACGEN") == "true" {
-		input, err := ioutil.ReadAll(os.Stdin)
-		secret := os.Getenv("SECRET")
-		if err != nil {
-			panic(err.Error())
-		}
-		fmt.Println(getSha256HMACSignature([]byte(secret), string(input)))
-		return
-	}
 	r := mux.NewRouter()
-	r.HandleFunc("/webhook/{service}", webhook)
-
-	port := ":80"
-	if p, ok := os.LookupEnv("PORT"); ok {
-		port = fmt.Sprintf(":%v", p)
-	}
+	r.HandleFunc("/webhooks/{service}", webhookHandler)
 
 	if p, ok := os.LookupEnv("CONFIG"); ok {
 		config_filename = p
 	}
 
-	log.Fatal(http.ListenAndServe(port, r))
+	if p, ok := os.LookupEnv("NO_SIGNATURE_CHECK"); ok {
+		checkSignature = p != "true"
 	}
 
-func webhook(w http.ResponseWriter, r *http.Request) {
-	// TODO run any specified tests before running script
+	raw_config, err := os.ReadFile(config_filename)
+	if err != nil {
+		panic(err.Error())
+	}
 
-	service_name := mux.Vars(r)["service"]
+	if err := json.Unmarshal(raw_config, &c); err != nil {
+		panic(err.Error())
+	}
 
+	if err := c.Validate(); err != nil {
+		panic(err.Error())
+	}
+
+	log.Fatal(http.ListenAndServe(c.ListenAddress, r))
+}
+
+func webhookHandler(w http.ResponseWriter, r *http.Request) {
+	// Check what service is specified in URL (/webhooks/{service}) and if it exists
+	serviceName := string(mux.Vars(r)["service"])
+	service, ok := c.Services[serviceName]
+	if !ok {
+		writeResponse(w, 404, "Service Not Found")
+		fmt.Printf("Service not found: %v\n", serviceName)
+		return
+	}
+	fmt.Printf("Got webhook for: %v\n", serviceName)
+
+	// Read payload or return 500 if that doesn't work out
 	payload := ""
-	if p, err := ioutil.ReadAll(r.Body); err != nil {
+	if p, err := io.ReadAll(r.Body); err != nil {
 		writeResponse(w, 500, "Internal Server Error: Could not read payload")
+		fmt.Println("Error: Could not read payload")
 		return
 	} else {
 		payload = string(p)
 	}
 
-	raw_config, err := ioutil.ReadFile(config_filename)
-	if err != nil {
-		writeResponse(w, 500, "Internal Server Error: Could not open config file")
-		return
-	}
-	config := Config{}
-	json.Unmarshal(raw_config, &config)
-
-	var service = Service{}
-	if val, ok := config.Services[string(service_name)]; !ok {
-		writeResponse(w, 404, "Service Not Found")
-		return
-	} else {
-		service = val
-	}
-
+	// Verify that signature provided matches signature calculated using secretsss
 	signature := r.Header.Get(service.SignatureHeader)
-	if signature == getSha256HMACSignature([]byte(service.Secret), payload) {
+	calculatedSignature := fmt.Sprintf(
+		"%v%v",
+		service.SignaturePrefix,
+		getSha256HMACSignature([]byte(service.Secret), payload),
+	)
+	fmt.Printf("signature          = %v\n", signature)
+	fmt.Printf("calcuatedSignature = %v\n", calculatedSignature)
+	if checkSignature && !service.DisableSignatureVerification && signature != calculatedSignature {
 		writeResponse(w, 400, "Bad Request: Signatures do not match")
+		fmt.Println("Signatures do not match!")
 		return
 	}
 
-	if stdout, err := exec.Command(service.Script, payload).Output(); err != nil {
-		writeResponse(w, 500, err.Error())
-		return
-	} else {
-		writeResponse(w, 200, string(stdout))
+	// Run tests and script as goroutine to prevent timing out
+	go func() {
+		// Run tests, immediately stop if one fails
+		for _, test := range service.Tests {
+			if _, err := test.Execute(payload, r.Header); err != nil {
+				fmt.Printf("Test failed(%v) for service %v\n", test, serviceName)
 				return
 			}
 		}
+		stdout, err := service.Script.Execute(payload, r.Header)
+		fmt.Println(string(stdout))
+		if err != nil {
+			fmt.Println(err.Error())
+		}
+	}()
+
+	writeResponse(w, 200, "OK")
+	return
+}
 
 func writeResponse(w http.ResponseWriter, responseCode int, responseString string) {
 	w.WriteHeader(responseCode)
@@ -98,15 +113,3 @@ func getSha256HMACSignature(secret []byte, data string) string {
 	io.WriteString(h, data)
 	return hex.EncodeToString(h.Sum(nil))
 }
-
-type Service struct {
-	Gitea           bool
-	Script          string
-	Secret          string
-	SignatureHeader string
-	Tests           []string
-}
-
-type Config struct {
-	Services map[string]Service
-}

readme.md

@@ -1,7 +1,100 @@
 # gohookr
 
-A _really_ simple webhook receiver.
+A _really_ simple webhook receiver, which listens at `/webhooks/<webhook-name>`.
 
-Check config.json for an example configuration.
+## Installation
 
-Default config path is `/etc/ghookr.conf`, can be overriden with `CONFIG` environment variable.
+After you [install go](https://golang.org/doc/install):
+
+```
+make
+```
+
+## Configuration
+
+Default config path is `/etc/gohookr.json`.
+It can be overriden by setting environment variable `CONFIG`.
+
+Check below for an example configuration, which should tell you most of the things you need to know
+to configure gohookr.
+
+Currently gohookr must be restarted after config changes.
+
+### Signature Verification
+
+Signature verificaiton is done using SHA256 HMACs.
+You **must** set which HTTP header gohookr will receive a signature from using the `SignatureHeader`
+key for each service.
+You should also specify a shared secret in the `Secret` key.
+
+You may also need to specify a `SignaturePrefix`.
+For GitHub it would be `sha256=`.
+
+#### Disable Signature Verification
+
+You can disable signature verification by setting `DisableSignatureVerification` for a service to `true`.
+
+You can disable signature verification for all services by setting environment variable
+`NO_SIGNATURE_VERIFICATION` to `true`.
+
+### Writing Commands
+
+gohookr doesn't care what the command is as long as the `Program` is executable.
+You can specify extra arguments with the `Arguments` field.
+You can ask it to put the payload as the last (or second to last if `AppendHeaders` is set) argument by setting `AppendPayload` to true.
+You can ask it to put the request headers as the last argument by setting `AppendHeaders` to true.
+
+### Writing Tests
+
+gohookr can run test before running your script.
+Tests must be in the form of bash scripts.
+A non-zero return code is considered a fail and gohookr will run no further tests and will not
+deploy.
+
+Tests are run in the order they're listed so any actions that need to be done before
+tests are run can simply be put in this section before the tests.
+
+### Example Config
+
+Required config keys are `ListenAddress` and `Services`.
+
+Requried keys per service are `Script.Program`, `Secret`, `SignatureHeader`.
+
+An example config file can be found [here](./config.json) but also below:
+
+```json
+{
+  "ListenAddress": "127.0.0.1:8654",
+  "Services": {
+    "test": {
+      "Script": {
+          "Program": "./example.sh",
+          "AppendPayload": true,
+          "AppendHeaders": true
+      },
+      "DisableSignatureVerification": true,
+      "Tests": [
+        {
+          "Program": "echo",
+          "Arguments": [ "test" ]
+        }
+      ]
+    },
+    "fails_tests": {
+      "Script": {
+          "Program": "./example.sh",
+          "AppendPayload": true
+      },
+      "Secret": "who_cares",
+      "SignatureHeader": "X-Hub-Signature-256",
+      "SignaturePrefix": "sha256=",
+      "Tests": [
+        {
+          "Program": "false",
+          "Arguments": []
+        }
+      ]
+    }
+  }
+}
+```