[minor] use google default application credentials

.gitignore

@@ -0,0 +1 @@
+lightsout

go.mod

@@ -1,3 +1,33 @@
 module github.com/libops/lightsout
 
 go 1.25.3
+
+require (
+	golang.org/x/oauth2 v0.33.0
+	google.golang.org/api v0.256.0
+)
+
+require (
+	cloud.google.com/go/auth v0.17.0 // indirect
+	cloud.google.com/go/auth/oauth2adapt v0.2.8 // indirect
+	cloud.google.com/go/compute/metadata v0.9.0 // indirect
+	github.com/felixge/httpsnoop v1.0.4 // indirect
+	github.com/go-logr/logr v1.4.3 // indirect
+	github.com/go-logr/stdr v1.2.2 // indirect
+	github.com/google/s2a-go v0.1.9 // indirect
+	github.com/google/uuid v1.6.0 // indirect
+	github.com/googleapis/enterprise-certificate-proxy v0.3.7 // indirect
+	github.com/googleapis/gax-go/v2 v2.15.0 // indirect
+	go.opentelemetry.io/auto/sdk v1.2.1 // indirect
+	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.63.0 // indirect
+	go.opentelemetry.io/otel v1.38.0 // indirect
+	go.opentelemetry.io/otel/metric v1.38.0 // indirect
+	go.opentelemetry.io/otel/trace v1.38.0 // indirect
+	golang.org/x/crypto v0.45.0 // indirect
+	golang.org/x/net v0.47.0 // indirect
+	golang.org/x/sys v0.38.0 // indirect
+	golang.org/x/text v0.31.0 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20251124214823-79d6a2a48846 // indirect
+	google.golang.org/grpc v1.77.0 // indirect
+	google.golang.org/protobuf v1.36.10 // indirect
+)

go.sum

@@ -0,0 +1,73 @@
+cloud.google.com/go/auth v0.17.0 h1:74yCm7hCj2rUyyAocqnFzsAYXgJhrG26XCFimrc/Kz4=
+cloud.google.com/go/auth v0.17.0/go.mod h1:6wv/t5/6rOPAX4fJiRjKkJCvswLwdet7G8+UGXt7nCQ=
+cloud.google.com/go/auth/oauth2adapt v0.2.8 h1:keo8NaayQZ6wimpNSmW5OPc283g65QNIiLpZnkHRbnc=
+cloud.google.com/go/auth/oauth2adapt v0.2.8/go.mod h1:XQ9y31RkqZCcwJWNSx2Xvric3RrU88hAYYbjDWYDL+c=
+cloud.google.com/go/compute/metadata v0.9.0 h1:pDUj4QMoPejqq20dK0Pg2N4yG9zIkYGdBtwLoEkH9Zs=
+cloud.google.com/go/compute/metadata v0.9.0/go.mod h1:E0bWwX5wTnLPedCKqk3pJmVgCBSM6qQI1yTBdEb3C10=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/felixge/httpsnoop v1.0.4 h1:NFTV2Zj1bL4mc9sqWACXbQFVBBg2W3GPvqp8/ESS2Wg=
+github.com/felixge/httpsnoop v1.0.4/go.mod h1:m8KPJKqk1gH5J9DgRY2ASl2lWCfGKXixSwevea8zH2U=
+github.com/go-logr/logr v1.2.2/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=
+github.com/go-logr/logr v1.4.3 h1:CjnDlHq8ikf6E492q6eKboGOC0T8CDaOvkHCIg8idEI=
+github.com/go-logr/logr v1.4.3/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
+github.com/go-logr/stdr v1.2.2 h1:hSWxHoqTgW2S2qGc0LTAI563KZ5YKYRhT3MFKZMbjag=
+github.com/go-logr/stdr v1.2.2/go.mod h1:mMo/vtBO5dYbehREoey6XUKy/eSumjCCveDpRre4VKE=
+github.com/golang/protobuf v1.5.4 h1:i7eJL8qZTpSEXOPTxNKhASYpMn+8e5Q6AdndVa1dWek=
+github.com/golang/protobuf v1.5.4/go.mod h1:lnTiLA8Wa4RWRcIUkrtSVa5nRhsEGBg48fD6rSs7xps=
+github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
+github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
+github.com/google/s2a-go v0.1.9 h1:LGD7gtMgezd8a/Xak7mEWL0PjoTQFvpRudN895yqKW0=
+github.com/google/s2a-go v0.1.9/go.mod h1:YA0Ei2ZQL3acow2O62kdp9UlnvMmU7kA6Eutn0dXayM=
+github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
+github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/googleapis/enterprise-certificate-proxy v0.3.7 h1:zrn2Ee/nWmHulBx5sAVrGgAa0f2/R35S4DJwfFaUPFQ=
+github.com/googleapis/enterprise-certificate-proxy v0.3.7/go.mod h1:MkHOF77EYAE7qfSuSS9PU6g4Nt4e11cnsDUowfwewLA=
+github.com/googleapis/gax-go/v2 v2.15.0 h1:SyjDc1mGgZU5LncH8gimWo9lW1DtIfPibOG81vgd/bo=
+github.com/googleapis/gax-go/v2 v2.15.0/go.mod h1:zVVkkxAQHa1RQpg9z2AUCMnKhi0Qld9rcmyfL1OZhoc=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
+github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
+go.opentelemetry.io/auto/sdk v1.2.1 h1:jXsnJ4Lmnqd11kwkBV2LgLoFMZKizbCi5fNZ/ipaZ64=
+go.opentelemetry.io/auto/sdk v1.2.1/go.mod h1:KRTj+aOaElaLi+wW1kO/DZRXwkF4C5xPbEe3ZiIhN7Y=
+go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.63.0 h1:RbKq8BG0FI8OiXhBfcRtqqHcZcka+gU3cskNuf05R18=
+go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.63.0/go.mod h1:h06DGIukJOevXaj/xrNjhi/2098RZzcLTbc0jDAUbsg=
+go.opentelemetry.io/otel v1.38.0 h1:RkfdswUDRimDg0m2Az18RKOsnI8UDzppJAtj01/Ymk8=
+go.opentelemetry.io/otel v1.38.0/go.mod h1:zcmtmQ1+YmQM9wrNsTGV/q/uyusom3P8RxwExxkZhjM=
+go.opentelemetry.io/otel/metric v1.38.0 h1:Kl6lzIYGAh5M159u9NgiRkmoMKjvbsKtYRwgfrA6WpA=
+go.opentelemetry.io/otel/metric v1.38.0/go.mod h1:kB5n/QoRM8YwmUahxvI3bO34eVtQf2i4utNVLr9gEmI=
+go.opentelemetry.io/otel/sdk v1.38.0 h1:l48sr5YbNf2hpCUj/FoGhW9yDkl+Ma+LrVl8qaM5b+E=
+go.opentelemetry.io/otel/sdk v1.38.0/go.mod h1:ghmNdGlVemJI3+ZB5iDEuk4bWA3GkTpW+DOoZMYBVVg=
+go.opentelemetry.io/otel/sdk/metric v1.38.0 h1:aSH66iL0aZqo//xXzQLYozmWrXxyFkBJ6qT5wthqPoM=
+go.opentelemetry.io/otel/sdk/metric v1.38.0/go.mod h1:dg9PBnW9XdQ1Hd6ZnRz689CbtrUp0wMMs9iPcgT9EZA=
+go.opentelemetry.io/otel/trace v1.38.0 h1:Fxk5bKrDZJUH+AMyyIXGcFAPah0oRcT+LuNtJrmcNLE=
+go.opentelemetry.io/otel/trace v1.38.0/go.mod h1:j1P9ivuFsTceSWe1oY+EeW3sc+Pp42sO++GHkg4wwhs=
+golang.org/x/crypto v0.45.0 h1:jMBrvKuj23MTlT0bQEOBcAE0mjg8mK9RXFhRH6nyF3Q=
+golang.org/x/crypto v0.45.0/go.mod h1:XTGrrkGJve7CYK7J8PEww4aY7gM3qMCElcJQ8n8JdX4=
+golang.org/x/net v0.47.0 h1:Mx+4dIFzqraBXUugkia1OOvlD6LemFo1ALMHjrXDOhY=
+golang.org/x/net v0.47.0/go.mod h1:/jNxtkgq5yWUGYkaZGqo27cfGZ1c5Nen03aYrrKpVRU=
+golang.org/x/oauth2 v0.33.0 h1:4Q+qn+E5z8gPRJfmRy7C2gGG3T4jIprK6aSYgTXGRpo=
+golang.org/x/oauth2 v0.33.0/go.mod h1:lzm5WQJQwKZ3nwavOZ3IS5Aulzxi68dUSgRHujetwEA=
+golang.org/x/sync v0.18.0 h1:kr88TuHDroi+UVf+0hZnirlk8o8T+4MrK6mr60WkH/I=
+golang.org/x/sync v0.18.0/go.mod h1:9KTHXmSnoGruLpwFjVSX0lNNA75CykiMECbovNTZqGI=
+golang.org/x/sys v0.38.0 h1:3yZWxaJjBmCWXqhN1qh02AkOnCQ1poK6oF+a7xWL6Gc=
+golang.org/x/sys v0.38.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
+golang.org/x/text v0.31.0 h1:aC8ghyu4JhP8VojJ2lEHBnochRno1sgL6nEi9WGFGMM=
+golang.org/x/text v0.31.0/go.mod h1:tKRAlv61yKIjGGHX/4tP1LTbc13YSec1pxVEWXzfoeM=
+gonum.org/v1/gonum v0.16.0 h1:5+ul4Swaf3ESvrOnidPp4GZbzf0mxVQpDCYUQE7OJfk=
+gonum.org/v1/gonum v0.16.0/go.mod h1:fef3am4MQ93R2HHpKnLk4/Tbh/s0+wqD5nfa6Pnwy4E=
+google.golang.org/api v0.256.0 h1:u6Khm8+F9sxbCTYNoBHg6/Hwv0N/i+V94MvkOSor6oI=
+google.golang.org/api v0.256.0/go.mod h1:KIgPhksXADEKJlnEoRa9qAII4rXcy40vfI8HRqcU964=
+google.golang.org/genproto v0.0.0-20250603155806-513f23925822 h1:rHWScKit0gvAPuOnu87KpaYtjK5zBMLcULh7gxkCXu4=
+google.golang.org/genproto v0.0.0-20250603155806-513f23925822/go.mod h1:HubltRL7rMh0LfnQPkMH4NPDFEWp0jw3vixw7jEM53s=
+google.golang.org/genproto/googleapis/api v0.0.0-20251022142026-3a174f9686a8 h1:mepRgnBZa07I4TRuomDE4sTIYieg/osKmzIf4USdWS4=
+google.golang.org/genproto/googleapis/api v0.0.0-20251022142026-3a174f9686a8/go.mod h1:fDMmzKV90WSg1NbozdqrE64fkuTv6mlq2zxo9ad+3yo=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20251124214823-79d6a2a48846 h1:Wgl1rcDNThT+Zn47YyCXOXyX/COgMTIdhJ717F0l4xk=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20251124214823-79d6a2a48846/go.mod h1:7i2o+ce6H/6BluujYR+kqX3GKH+dChPTQU19wjRPiGk=
+google.golang.org/grpc v1.77.0 h1:wVVY6/8cGA6vvffn+wWK5ToddbgdU3d8MNENr4evgXM=
+google.golang.org/grpc v1.77.0/go.mod h1:z0BY1iVj0q8E1uSQCjL9cppRj+gnZjzDnzV0dHhrNig=
+google.golang.org/protobuf v1.36.10 h1:AYd7cD/uASjIL6Q9LiTjz8JLcrh/88q5UObnmY3aOOE=
+google.golang.org/protobuf v1.36.10/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

main.go

@@ -2,7 +2,6 @@ package main
 
 import (
 	"context"
-	"encoding/json"
 	"fmt"
 	"log/slog"
 	"net/http"
@@ -14,6 +13,10 @@ import (
 	"sync"
 	"syscall"
 	"time"
+
+	"golang.org/x/oauth2/google"
+	compute "google.golang.org/api/compute/v1"
+	"google.golang.org/api/option"
 )
 
 type Config struct {
@@ -26,16 +29,6 @@ type Config struct {
 	GCEInstance       string
 }
 
-type AccessToken struct {
-	AccessToken string `json:"access_token"`
-	ExpiresIn   int    `json:"expires_in"`
-	TokenType   string `json:"token_type"`
-}
-
-type ComputeInstance struct {
-	Status string `json:"status"`
-}
-
 type ActivityTracker struct {
 	mu           sync.RWMutex
 	requestCount int64
@@ -162,115 +155,57 @@ func getLastGitHubActionsActivity() (time.Time, error) {
 	return time.Time{}, fmt.Errorf("could not parse github-actions timestamp")
 }
 
-func getAccessToken() (AccessToken, error) {
-	t := AccessToken{}
-
-	req, err := http.NewRequest("GET", "http://metadata.google.internal/computeMetadata/v1/instance/service-accounts/default/token", nil)
+func createComputeService(ctx context.Context) (*compute.Service, error) {
+	// Use Application Default Credentials (ADC)
+	// This will automatically use:
+	// 1. GOOGLE_APPLICATION_CREDENTIALS environment variable
+	// 2. GCE metadata server (when running on GCE)
+	// 3. gcloud CLI credentials
+	creds, err := google.FindDefaultCredentials(ctx, compute.ComputeScope)
 	if err != nil {
-		return t, err
+		return nil, fmt.Errorf("failed to find default credentials: %w", err)
 	}
-	req.Header.Set("Metadata-Flavor", "Google")
 
-	client := &http.Client{Timeout: 10 * time.Second}
-	resp, err := client.Do(req)
+	service, err := compute.NewService(ctx, option.WithCredentials(creds))
 	if err != nil {
-		return t, err
-	}
-	defer resp.Body.Close()
-
-	if resp.StatusCode != http.StatusOK {
-		return t, fmt.Errorf("fetching token non-200: %d", resp.StatusCode)
+		return nil, fmt.Errorf("failed to create compute service: %w", err)
 	}
 
-	if err := json.NewDecoder(resp.Body).Decode(&t); err != nil {
-		return t, fmt.Errorf("failed to decode token response: %w", err)
-	}
-	return t, nil
-}
-
-func getMachineMetadata(token AccessToken, targetURL string) (ComputeInstance, error) {
-	vm := ComputeInstance{}
-
-	req, err := http.NewRequest("GET", targetURL, nil)
-	if err != nil {
-		return vm, err
-	}
-	req.Header.Set("Authorization", "Bearer "+token.AccessToken)
-
-	client := &http.Client{Timeout: 30 * time.Second}
-	resp, err := client.Do(req)
-	if err != nil {
-		return vm, err
-	}
-	defer resp.Body.Close()
-
-	if resp.StatusCode != http.StatusOK {
-		return vm, fmt.Errorf("getMachineMetadata non-200: %d", resp.StatusCode)
-	}
-
-	if err := json.NewDecoder(resp.Body).Decode(&vm); err != nil {
-		return vm, fmt.Errorf("failed to decode instance metadata: %w", err)
-	}
-	return vm, nil
-}
-
-func performInstanceAction(token AccessToken, targetURL, action string) error {
-	actionURL := targetURL + "/" + action
-
-	req, err := http.NewRequest("POST", actionURL, nil)
-	if err != nil {
-		return err
-	}
-	req.Header.Set("Authorization", "Bearer "+token.AccessToken)
-
-	client := &http.Client{Timeout: 30 * time.Second}
-	resp, err := client.Do(req)
-	if err != nil {
-		return err
-	}
-	defer resp.Body.Close()
-
-	if resp.StatusCode != http.StatusOK {
-		return fmt.Errorf("performInstanceAction non-200: %d", resp.StatusCode)
-	}
-
-	return nil
+	return service, nil
 }
 
-func suspendMachine() (ComputeInstance, error) {
-	targetURL := fmt.Sprintf("https://compute.googleapis.com/compute/v1/projects/%s/zones/%s/instances/%s",
-		config.GoogleProjectID, config.GCEZone, config.GCEInstance)
+func suspendMachine() (*compute.Instance, error) {
+	ctx := context.Background()
 
 	slog.Info("Checking if machine is suspended",
 		"project", config.GoogleProjectID,
 		"zone", config.GCEZone,
 		"instance", config.GCEInstance)
 
-	// get access token
-	t, err := getAccessToken()
+	// Create compute service with default credentials
+	service, err := createComputeService(ctx)
 	if err != nil {
-		return ComputeInstance{}, fmt.Errorf("getAccessToken: %v", err)
+		return nil, fmt.Errorf("createComputeService: %v", err)
 	}
 
-	// get machine metadata
-	vm, err := getMachineMetadata(t, targetURL)
+	// Get instance details
+	instance, err := service.Instances.Get(config.GoogleProjectID, config.GCEZone, config.GCEInstance).Context(ctx).Do()
 	if err != nil {
-		return vm, fmt.Errorf("getMachineMetadata: %v", err)
+		return nil, fmt.Errorf("failed to get instance: %v", err)
 	}
 
-	// if the machine is running, suspend it
-	if vm.Status == "RUNNING" {
-		action := "suspend"
+	// If the machine is running, suspend it
+	if instance.Status == "RUNNING" {
 		slog.Info("Instance is RUNNING, suspending instance")
-		err := performInstanceAction(t, targetURL, action)
+		_, err := service.Instances.Suspend(config.GoogleProjectID, config.GCEZone, config.GCEInstance).Context(ctx).Do()
 		if err != nil {
-			return vm, fmt.Errorf("performInstanceAction: %v", err)
+			return instance, fmt.Errorf("failed to suspend instance: %v", err)
 		}
 	} else {
-		slog.Info("Instance is not RUNNING, skipping suspension", "status", vm.Status)
+		slog.Info("Instance is not RUNNING, skipping suspension", "status", instance.Status)
 	}
 
-	return vm, nil
+	return instance, nil
 }
 
 func suspendInstance() error {