initial import

.gitignore

@@ -0,0 +1 @@
+go-github-apps

README.md

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+# go-github-apps
+
+`go-github-apps` is a command-line tool to retrieve a github access token for your Github Apps.
+
+When you want to call Github APIs from machines, you would want an access token which independs of a real account.
+Github provides several ways to issue tokens, for example:
+- Issue Personal Access Token via machine-user: Before Github Apps exists, this is typical method to issue a token but it consumes one user seats.
+- Create Github Apps and issue a token for the app: This is a new way and recommended way. The problem is [it's not that easy to issue a token](https://docs.github.com/en/developers/apps/authenticating-with-github-apps#authenticating-as-a-github-app) just to automate small stuff.
+
+This command-line tool allows you to get a token with just providing `App ID`, `Installation ID` and the private key.
+
+## Usage
+
+```sh
+Usage of go-github-apps:
+  -app-id int
+    	App ID
+  -export
+    	show token as 'export GITHUB_TOKEN=...'
+  -inst-id int
+    	Installation ID
+```
+
+**Example**:
+```sh
+export GITHUB_PRIV_KEY=$(cat your-apps-2020-08-07.private-key.pem)
+eval $(go-github-apps -export -app-id 12345 -inst-id 123456)
+
+# github token is now exported to GITHUB_TOKEN environment variable
+```
+
+## AppID and Installation ID
+
+You can find how to get those ID at https://github.com/bradleyfalzon/ghinstallation#what-is-app-id-and-installation-id

go.mod

@@ -0,0 +1,9 @@
+module github.com/nabeken/go-github-apps
+
+go 1.14
+
+require (
+	github.com/bradleyfalzon/ghinstallation v1.1.1
+	github.com/google/go-github/v29 v29.0.3
+	golang.org/x/crypto v0.0.0-20200728195943-123391ffb6de // indirect
+)

go.sum

@@ -0,0 +1,23 @@
+github.com/bradleyfalzon/ghinstallation v1.1.1 h1:pmBXkxgM1WeF8QYvDLT5kuQiHMcmf+X015GI0KM/E3I=
+github.com/bradleyfalzon/ghinstallation v1.1.1/go.mod h1:vyCmHTciHx/uuyN82Zc3rXN3X2KTK8nUTCrTMwAhcug=
+github.com/dgrijalva/jwt-go v3.2.0+incompatible h1:7qlOGliEKZXTDg6OTjfoBKDXWrumCAMpl/TFQ4/5kLM=
+github.com/dgrijalva/jwt-go v3.2.0+incompatible/go.mod h1:E3ru+11k8xSBh+hMPgOLZmtrrCbhqsmaPHjLKYnJCaQ=
+github.com/golang/protobuf v1.3.2/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
+github.com/google/go-cmp v0.3.1/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
+github.com/google/go-github/v29 v29.0.2 h1:opYN6Wc7DOz7Ku3Oh4l7prmkOMwEcQxpFtxdU8N8Pts=
+github.com/google/go-github/v29 v29.0.2/go.mod h1:CHKiKKPHJ0REzfwc14QMklvtHwCveD0PxlMjLlzAM5E=
+github.com/google/go-github/v29 v29.0.3 h1:IktKCTwU//aFHnpA+2SLIi7Oo9uhAzgsdZNbcAqhgdc=
+github.com/google/go-github/v29 v29.0.3/go.mod h1:CHKiKKPHJ0REzfwc14QMklvtHwCveD0PxlMjLlzAM5E=
+github.com/google/go-querystring v1.0.0 h1:Xkwi/a1rcvNg1PPYe5vI8GbeBY/jrVuDX5ASuANWTrk=
+github.com/google/go-querystring v1.0.0/go.mod h1:odCYkC5MyYFN7vkCjXpyrEuKhc/BUO6wN/zVPAxq5ck=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2 h1:VklqNMn3ovrHsnt90PveolxSbWFaJdECFbxSq0Mqo2M=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20200728195943-123391ffb6de h1:ikNHVSjEfnvz6sxdSPCaPt572qowuyMDMJLLm3Db3ig=
+golang.org/x/crypto v0.0.0-20200728195943-123391ffb6de/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
+golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+google.golang.org/appengine v1.1.0/go.mod h1:EbEs0AVv82hx2wNQdGPgUI5lhzA/G0D9YwlJXL52JkM=

main.go

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+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+	"time"
+
+	"github.com/bradleyfalzon/ghinstallation"
+)
+
+func main() {
+	appID := flag.Int64("app-id", 0, "App ID")
+	instID := flag.Int64("inst-id", 0, "Installation ID")
+	export := flag.Bool("export", false, "show token as 'export GITHUB_TOKEN=...'")
+	flag.Parse()
+
+	if *appID == 0 || *instID == 0 {
+		fmt.Fprintf(os.Stderr, "App ID and Installation ID are required.\n\n")
+		flag.Usage()
+		os.Exit(1)
+	}
+
+	key := os.Getenv("GITHUB_PRIV_KEY")
+	if key == "" {
+		log.Fatal("Please populate GITHUB_PRIV_KEY environment variable with the private key for the App")
+	}
+
+	// Wrap the shared transport for use with the app ID 1 authenticating with installation ID 99.
+	itr, err := ghinstallation.New(http.DefaultTransport, *appID, *instID, []byte(key))
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), time.Minute)
+	defer cancel()
+
+	token, err := itr.Token(ctx)
+	if err != nil {
+		log.Fatalf("unable to get github token: %s", err)
+	}
+
+	if *export {
+		showExport(token)
+	} else {
+		fmt.Println(token)
+	}
+}
+
+func showExport(token string) {
+	fmt.Printf("export GITHUB_TOKEN=%s\n", token)
+}