feat: Add support for GCP secret manager (#66)

* feat: Add support for GCP secret manager
- Users can store github private keys in GCP secret manager
- Tested in GKE with workload identity

README.md

@@ -14,11 +14,18 @@ Key features:
 - Uses a custom resource `GithubApp` in your destination namespace.
 - Reads `appId`, `installId` and either and `privateKeySecret` or `vaultPrivateKey` defined in a `GithubApp` resource and requests an access token from Github for the Github App.
   - It stores the access token in a secret as per `accessTokenSecret`
-- For pulling a GitHub Apps private key, there are 2 options built-in:
+- For pulling a GitHub Apps private key, there are 3 options built-in:
   - Using a Kubernetes secret:
     - Use `privateKeySecret` - refers to an existing secret in the namespace which holds the base64 encoded PEM of the Github App's private key.
     - It expects the field `data.privateKey` in the secret to pull the private key from.
-  - Hashicorp Vault (this takes priority over `privateKeySecret` if both are specified):
+  - Using GCP Secret Manager (this takes priority over `privateKeySecret` if it is specified):
+    - **You must base64 encode your private key before saving in Secret Manager**
+      - The operator logic will only accept base64 encoded secrets else it will fail.
+    - Configure with the `googlePrivateKeySecret` - the full secret path in Secret Manager for your GithubApp secret
+      - i.e. "projects/xxxxxxxxxx/secrets/my-gh-app/versions/latest"
+    - Configure [Workload Identity](https://cloud.google.com/kubernetes-engine/docs/how-to/workload-identity) to bind secret access permissions to the operators Kubernetes Service Account
+        - Tested with role `roles/secretmanager.secretAccessor`
+  - Hashicorp Vault (this takes priority over `privateKeySecret` and `googlePrivateKeySecret` if they are specified):
     - **You must base64 encode your private key before saving in Vault**
       - The operator logic will only accept base64 encoded secrets else it will fail.
     - This will create a short-lived JWT (10mins TTL) via Kubernetes Token Request API, with an audience you define.
@@ -144,6 +151,24 @@ spec:
 EOF
 ```
 
+## Example GithubApp object using GCP Secret Manager to pull the private key during run-time
+- Below example will fetch the private key from GCP Secret Manager when the github access token expires
+- It requires that the Kubernetes Service Account has permissions on the secret in SEcret Manager, i.e. via [Workload Identity](https://cloud.google.com/kubernetes-engine/docs/how-to/workload-identity)
+```sh
+kubectl apply -f - <<EOF
+apiVersion: githubapp.samir.io/v1
+kind: GithubApp
+metadata:
+  name: GithubApp-sample
+  namespace: team-1
+spec:
+  appId: 123123
+  installId: 12312312
+  accessTokenSecret: github-app-access-token-123123
+  googlePrivateKeySecret: "projects/123123123123/secrets/gh-app-123123/versions/latest"
+EOF
+```
+
 ## Getting Started
 
 ### Prerequisites

api/v1/githubapp_types.go

@@ -22,12 +22,13 @@ import (
 
 // GithubAppSpec defines the desired state of GithubApp
 type GithubAppSpec struct {
-	AppId             int                    `json:"appId"`
-	InstallId         int                    `json:"installId"`
-	PrivateKeySecret  string                 `json:"privateKeySecret,omitempty"`
-	RolloutDeployment *RolloutDeploymentSpec `json:"rolloutDeployment,omitempty"`
-	VaultPrivateKey   *VaultPrivateKeySpec   `json:"vaultPrivateKey,omitempty"`
-	AccessTokenSecret string                 `json:"accessTokenSecret"`
+	AppId               int                    `json:"appId"`
+	InstallId           int                    `json:"installId"`
+	PrivateKeySecret    string                 `json:"privateKeySecret,omitempty"`
+	RolloutDeployment   *RolloutDeploymentSpec `json:"rolloutDeployment,omitempty"`
+	VaultPrivateKey     *VaultPrivateKeySpec   `json:"vaultPrivateKey,omitempty"`
+	AccessTokenSecret   string                 `json:"accessTokenSecret"`
+	GcpPrivateKeySecret string                 `json:"googlePrivateKeySecret,omitempty"`
 }
 
 // GithubAppStatus defines the observed state of GithubApp

config/crd/bases/githubapp.samir.io_githubapps.yaml

@@ -59,6 +59,8 @@ spec:
                 type: string
               appId:
                 type: integer
+              googlePrivateKeySecret:
+                type: string
               installId:
                 type: integer
               privateKeySecret:

go.mod

@@ -16,15 +16,22 @@ require (
 )
 
 require (
+	cloud.google.com/go/auth v0.7.0 // indirect
+	cloud.google.com/go/auth/oauth2adapt v0.2.2 // indirect
+	cloud.google.com/go/compute/metadata v0.4.0 // indirect
+	cloud.google.com/go/iam v1.1.10 // indirect
+	cloud.google.com/go/secretmanager v1.13.4 // indirect
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/cenkalti/backoff/v3 v3.2.2 // indirect
 	github.com/cespare/xxhash/v2 v2.2.0 // indirect
 	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
 	github.com/emicklei/go-restful/v3 v3.11.0 // indirect
 	github.com/evanphx/json-patch/v5 v5.9.0 // indirect
+	github.com/felixge/httpsnoop v1.0.4 // indirect
 	github.com/fsnotify/fsnotify v1.7.0 // indirect
 	github.com/go-jose/go-jose/v4 v4.0.1 // indirect
 	github.com/go-logr/logr v1.4.1 // indirect
+	github.com/go-logr/stdr v1.2.2 // indirect
 	github.com/go-logr/zapr v1.3.0 // indirect
 	github.com/go-openapi/jsonpointer v0.20.0 // indirect
 	github.com/go-openapi/jsonreference v0.20.2 // indirect
@@ -38,7 +45,10 @@ require (
 	github.com/google/go-cmp v0.6.0 // indirect
 	github.com/google/gofuzz v1.2.0 // indirect
 	github.com/google/pprof v0.0.0-20210720184732-4bb14d4b1be1 // indirect
+	github.com/google/s2a-go v0.1.7 // indirect
 	github.com/google/uuid v1.6.0 // indirect
+	github.com/googleapis/enterprise-certificate-proxy v0.3.2 // indirect
+	github.com/googleapis/gax-go/v2 v2.12.5 // indirect
 	github.com/hashicorp/errwrap v1.1.0 // indirect
 	github.com/hashicorp/go-cleanhttp v0.5.2 // indirect
 	github.com/hashicorp/go-multierror v1.1.1 // indirect
@@ -68,20 +78,32 @@ require (
 	github.com/ryanuber/go-glob v1.0.0 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect
 	github.com/stretchr/testify v1.9.0 // indirect
+	go.opencensus.io v0.24.0 // indirect
+	go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.49.0 // indirect
+	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.49.0 // indirect
+	go.opentelemetry.io/otel v1.24.0 // indirect
+	go.opentelemetry.io/otel/metric v1.24.0 // indirect
+	go.opentelemetry.io/otel/trace v1.24.0 // indirect
 	go.uber.org/multierr v1.11.0 // indirect
 	go.uber.org/zap v1.26.0 // indirect
-	golang.org/x/crypto v0.21.0 // indirect
+	golang.org/x/crypto v0.25.0 // indirect
 	golang.org/x/exp v0.0.0-20240222234643-814bf88cf225 // indirect
-	golang.org/x/net v0.23.0 // indirect
-	golang.org/x/oauth2 v0.18.0 // indirect
-	golang.org/x/sys v0.20.0 // indirect
-	golang.org/x/term v0.18.0 // indirect
-	golang.org/x/text v0.14.0 // indirect
+	golang.org/x/net v0.27.0 // indirect
+	golang.org/x/oauth2 v0.21.0 // indirect
+	golang.org/x/sync v0.7.0 // indirect
+	golang.org/x/sys v0.22.0 // indirect
+	golang.org/x/term v0.22.0 // indirect
+	golang.org/x/text v0.16.0 // indirect
 	golang.org/x/time v0.5.0 // indirect
-	golang.org/x/tools v0.18.0 // indirect
+	golang.org/x/tools v0.21.1-0.20240508182429-e35e4ccd0d2d // indirect
 	gomodules.xyz/jsonpatch/v2 v2.4.0 // indirect
+	google.golang.org/api v0.188.0 // indirect
 	google.golang.org/appengine v1.6.8 // indirect
-	google.golang.org/protobuf v1.33.0 // indirect
+	google.golang.org/genproto v0.0.0-20240708141625-4ad9e859172b // indirect
+	google.golang.org/genproto/googleapis/api v0.0.0-20240701130421-f6361c86f094 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20240708141625-4ad9e859172b // indirect
+	google.golang.org/grpc v1.64.1 // indirect
+	google.golang.org/protobuf v1.34.2 // indirect
 	gopkg.in/inf.v0 v0.9.1 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect