LOG-9171: Add GCP WIF support

Author: cahartma

Cargo.lock

@@ -331,9 +331,10 @@ prost = { workspace = true, optional = true }
 prost-reflect = { workspace = true, optional = true }
 prost-types = { workspace = true, optional = true }
 
-# GCP
-goauth = { version = "0.16.0", optional = true }
-smpl_jwt = { version = "0.8.0", default-features = false, optional = true }
+# GCP - using official googleapis/google-cloud-rust authentication library
+# Supports service accounts, external accounts (workload identity), and ADC
+# Version 1.6 required for full external account support
+google-cloud-auth = { version = "1.6", optional = true }
 
 # AMQP
 lapin = { version = "2.5.3", default-features = false, features = ["native-tls"], optional = true }
@@ -640,7 +641,7 @@ aws-core = [
 # Anything that requires Protocol Buffers.
 protobuf-build = ["dep:tonic-build", "dep:prost-build"]
 
-gcp = ["dep:base64", "dep:goauth", "dep:smpl_jwt"]
+gcp = ["dep:base64", "dep:google-cloud-auth"]
 
 # Enrichment Tables
 enrichment-tables = ["enrichment-tables-geoip", "enrichment-tables-mmdb", "enrichment-tables-memory"]

Cargo.toml

@@ -0,0 +1,222 @@
+# Google Cloud Platform Workload Identity Federation Support
+## Vector v0.54 Enhancement
+
+---
+
+## Summary
+
+Implement Google Cloud Platform (GCP) Workload Identity Federation (WIF) support in /viaq/vector v0.54, enabling **keyless authentication** for all GCP integrations.
+
+This enhancement eliminates the operational burden and security risks of managing service account keys while maintaining full backwards compatibility with existing deployments.
+
+### Key Features
+- ✅ Full WIF support across all GCP sinks and sources
+- ✅ Backward compatible with existing authentication methods
+- ✅ Production-ready and tested implementation
+
+---
+
+### Industry
+Google Cloud **recommends** Workload Identity Federation as the preferred authentication method for workloads running outside GCP, particularly in OpenShift environments. This is becoming a **requirement** for security-conscious enterprises and is mandated by many compliance frameworks.
+
+---
+
+### Auth Comparison
+
+**Traditional Auth (Static Keys - INSECURE):**
+```
+Collector Pod → Service Account Key (NEVER EXPIRES) → GCP APIs
+                     ↑
+              [Stored as secret]
+              [Can be copied anywhere]
+              [Persists in images/logs]
+              [Indefinite access if stolen]
+```
+
+**Workload Identity Federation (Dynamic Tokens - SECURE):**
+```
+Collector Pod → OpenShift Pod Token → GCP Token Exchange → Short-lived Token (1hr) → GCP APIs
+                  ↑                         ↓                        ↓
+         [Bound to pod identity]    [Logged & audited]      [Auto-refreshed]
+         [Cannot be copied]          [Traceable]             [Auto-expires]
+         [Terminates with pod]       [Revocable]             [Scoped access]
+```
+
+### Security Enhancement
+
+With WIF, there are **no long-lived credentials to protect**. Even if an attacker compromises a pod, they only gain access for the current token's remaining lifetime (maximum 1 hour).  Additionally, the token is cryptographically bound to that specific OpenShift workload identity, making it useless elsewhere.
+
+---
+
+### Implementation Details
+
+**Core Authentication Module** (`src/gcp.rs`)
+- Complete rewrite using official Google authentication library
+- Support for multiple OAuth scopes
+- Automatic token refresh handling
+- Thread-safe credential management
+
+**GCP Sinks** (Data Destinations)
+- `gcp_cloud_storage` - Cloud Storage bucket output
+- `gcp_pubsub` - Pub/Sub topic publishing
+- `gcp_stackdriver_logs` - Cloud Logging
+- `gcp_stackdriver_metrics` - Cloud Monitoring
+- `gcp_chronicle` - Chronicle Security
+
+### Cargo
+```toml
+# Before
+goauth = "0.16.0"
+smpl_jwt = "0.8.0"
+
+# After
+google-cloud-auth = "1.6"  # Official Google library with full WIF support    woot!
+```
+
+
+
+### New "type" of Credentials File
+```json
+{
+  "type": "external_account",
+  "audience": "//iam.googleapis.com/projects/PROJECT_NUM/locations/global/workloadIdentityPools/POOL/providers/PROVIDER",
+  "subject_token_type": "urn:ietf:params:oauth:token-type:jwt",
+  "token_url": "https://sts.googleapis.com/v1/token",
+  "credential_source": {
+    "file": "/var/run/ocp-collector/serviceaccount/token"
+  },
+  "service_account_impersonation_url": "https://iamcredentials.googleapis.com/v1/projects/-/serviceAccounts/SA@PROJECT.iam.gserviceaccount.com:generateAccessToken"
+}
+```
+
+---
+
+### Benefits
+
+- ✅ **Zero Key Management:** No rotation schedules, no distribution pipelines, no key tracking
+  - Eliminates entire category of operational incidents
+  - No "emergency key rotation" fire drills
+  - No secret management infrastructure needed
+
+- ✅ **Least Privilege Access:** Tokens are scoped to specific GCP APIs and resources
+  - Fine-grained IAM policies per workload
+  - No over-privileged "one key for everything" scenarios
+
+- ✅ **Complete Audit Trail:** Every authentication is logged and traceable
+  - GCP Cloud Audit Logs show which OpenShift pod accessed which resource
+  - Token exchange events provide forensic evidence
+  - Real-time detection of unauthorized access attempts
+
+- ✅ **Multi-Cloud Support:** Works with AWS, Azure, and other identity providers
+- ✅ **Industry Best Practice:** Aligns with Google Cloud's **required** approach for modern workloads
+
+- ✅ **Risk Reduction:** Eliminates entire class of credential leakage incidents
+  - No more "key accidentally committed to GitHub" incidents
+  - No credential exposure via container image scanning
+  - Protection against supply chain attacks targeting secrets
+
+---
+### Testing
+
+**Unit Tests**
+```bash
+✓ gcp::tests::skip_authentication
+✓ gcp::tests::uses_api_key
+✓ gcp::tests::fails_bad_api_key
+```
+
+**Build Verification**
+```bash
+✓ Compiles with all GCP features
+✓ Rust 1.92 compatibility verified
+✓ No clippy warnings or errors
+```
+
+**Integration Testing**
+- GCP integration test suite available (`cargo vdev int test gcp`)
+- Tested with service account credentials
+- Verified with external account credentials (WIF)
+
+---
+
+## Authentication Priority
+
+Vector searches for credentials in this order:
+
+1. `api_key` (if configured)
+2. `credentials_path` (if configured) - supports both Service Account and External Account (WIF) files
+3. **Application Default Credentials (ADC)** - automatic fallback
+
+ADC searches: `GOOGLE_APPLICATION_CREDENTIALS` env var → gcloud CLI → GCE/GKE metadata server
+
+**Behavior Change**: When no explicit credentials are configured, Vector now attempts ADC instead of failing immediately. Tests renamed from `fails_missing_creds` to `falls_back_to_adc` to reflect this improvement.
+
+---
+
+## Steps
+
+**Step 1:** Create a GCP service account to be used by the ClusterLogForwarder:
+```bash
+gcloud iam service-accounts create SERVICE_ACCOUNT_NAME \
+  --display-name="OpenShift Logging Admin" \
+  --project=PROJECT_ID
+```
+
+**Step 2:** Bind Permissions to your Collector Service Account
+```bash
+# Allow OpenShift service account to impersonate GCP service account
+gcloud iam service-accounts add-iam-policy-binding SERVICE_ACCOUNT_NAME@project.iam.gserviceaccount.com \
+  --role=roles/iam.workloadIdentityUser \
+  --member="principal://iam.googleapis.com/projects/PROJECT_NUM/locations/global/workloadIdentityPools/POOL/subject/system:serviceaccount:NAMESPACE:MY_COLLECTOR_SERVICE_ACCOUNT"
+```
+
+**Step 3:** Generate a Configuration file for the External Account (Google Service Account)
+```bash
+gcloud iam workload-identity-pools create-cred-config \
+  projects/PROJECT_NUM/locations/global/workloadIdentityPools/POOL/providers/PROVIDER \
+  --service-account=SA@PROJECT.iam.gserviceaccount.com \
+  --output-file=external-account.json \
+  --credential-source-file=/var/run/ocp-collector/serviceaccount/token
+```
+
+**Step 4:** Create secret and configure ClusterLogForwarder
+
+```bash
+# Create secret in openshift-logging namespace
+oc create secret generic gcp-wif-credentials \
+  --from-file=credentials.json=external-account.json \
+  -n openshift-logging
+```
+
+**ClusterLogForwarder Configuration**:
+```yaml
+apiVersion: observability.openshift.io/v1
+kind: ClusterLogForwarder
+metadata:
+  name: instance
+  namespace: openshift-logging
+spec:
+  outputs:
+    - name: gcp-wif-logging
+      type: googleCloudLogging
+      googleCloudLogging:
+        id:
+          type: project
+          value: my-project123
+        logId: my-logs123
+        authentication:
+          credentials:
+            secretName: gcp-wif-credentials
+            key: external-account.json
+...
+# The external-account.json contains external account config (WIF)
+# Vector detects the credential type and uses appropriate auth flow
+```
+
+## References
+
+- **Google Cloud Documentation:** [Workload Identity Federation](https://cloud.google.com/iam/docs/workload-identity-federation)
+- **google-cloud-auth Library:** [Official Rust SDK](https://github.com/googleapis/google-cloud-rust)
+- **Vector Documentation:** [GCP Authentication](https://vector.dev/docs/reference/configuration/sinks/gcp_stackdriver_logs/#authentication)
+- **Ticket:** RH OpenShift LOG-9171
+- **Branch:** `v0.54.0-rh-gcp-wif`