use a single log writer

Use a single log writer instance for all std library logging.

Setup the std log writer in the logging package, and remove boilerplate
from test packages.

backend/local/local_test.go

@@ -2,24 +2,13 @@ package local
 
 import (
 	"flag"
-	"io/ioutil"
-	"log"
 	"os"
 	"testing"
 
-	"github.com/hashicorp/terraform/internal/logging"
+	_ "github.com/hashicorp/terraform/internal/logging"
 )
 
 func TestMain(m *testing.M) {
 	flag.Parse()
-
-	if testing.Verbose() {
-		// if we're verbose, use the logging requested by TF_LOG
-		logging.SetOutput()
-	} else {
-		// otherwise silence all logs
-		log.SetOutput(ioutil.Discard)
-	}
-
 	os.Exit(m.Run())
 }

backend/remote-state/inmem/backend_test.go

@@ -2,30 +2,20 @@ package inmem
 
 import (
 	"flag"
-	"io/ioutil"
-	"log"
 	"os"
 	"testing"
 
 	"github.com/hashicorp/hcl/v2"
 
 	"github.com/hashicorp/terraform/backend"
-	"github.com/hashicorp/terraform/internal/logging"
 	statespkg "github.com/hashicorp/terraform/states"
 	"github.com/hashicorp/terraform/states/remote"
+
+	_ "github.com/hashicorp/terraform/internal/logging"
 )
 
 func TestMain(m *testing.M) {
 	flag.Parse()
-
-	if testing.Verbose() {
-		// if we're verbose, use the logging requested by TF_LOG
-		logging.SetOutput()
-	} else {
-		// otherwise silence all logs
-		log.SetOutput(ioutil.Discard)
-	}
-
 	os.Exit(m.Run())
 }
 

backend/remote/remote_test.go

@@ -2,25 +2,15 @@ package remote
 
 import (
 	"flag"
-	"io/ioutil"
-	"log"
 	"os"
 	"testing"
 
-	"github.com/hashicorp/terraform/internal/logging"
+	_ "github.com/hashicorp/terraform/internal/logging"
 )
 
 func TestMain(m *testing.M) {
 	flag.Parse()
 
-	if testing.Verbose() {
-		// if we're verbose, use the logging requested by TF_LOG
-		logging.SetOutput()
-	} else {
-		// otherwise silence all logs
-		log.SetOutput(ioutil.Discard)
-	}
-
 	// Make sure TF_FORCE_LOCAL_BACKEND is unset
 	os.Unsetenv("TF_FORCE_LOCAL_BACKEND")
 

command/command_test.go

@@ -5,11 +5,9 @@ import (
 	"crypto/md5"
 	"encoding/base64"
 	"encoding/json"
-	"flag"
 	"fmt"
 	"io"
 	"io/ioutil"
-	"log"
 	"net/http"
 	"net/http/httptest"
 	"os"
@@ -30,7 +28,6 @@ import (
 	"github.com/hashicorp/terraform/configs/configload"
 	"github.com/hashicorp/terraform/configs/configschema"
 	"github.com/hashicorp/terraform/internal/copy"
-	"github.com/hashicorp/terraform/internal/logging"
 	"github.com/hashicorp/terraform/plans"
 	"github.com/hashicorp/terraform/plans/planfile"
 	"github.com/hashicorp/terraform/providers"
@@ -44,6 +41,7 @@ import (
 
 	backendInit "github.com/hashicorp/terraform/backend/init"
 	backendLocal "github.com/hashicorp/terraform/backend/local"
+	_ "github.com/hashicorp/terraform/internal/logging"
 )
 
 // These are the directories for our test data and fixtures.
@@ -83,15 +81,6 @@ func init() {
 func TestMain(m *testing.M) {
 	defer os.RemoveAll(testingDir)
 
-	flag.Parse()
-	if testing.Verbose() {
-		// if we're verbose, use the logging requested by TF_LOG
-		logging.SetOutput()
-	} else {
-		// otherwise silence all logs
-		log.SetOutput(ioutil.Discard)
-	}
-
 	// Make sure backend init is initialized, since our tests tend to assume it.
 	backendInit.Init(nil)
 

dag/dag_test.go

@@ -3,8 +3,6 @@ package dag
 import (
 	"flag"
 	"fmt"
-	"io/ioutil"
-	"log"
 	"os"
 	"reflect"
 	"strconv"
@@ -14,19 +12,11 @@ import (
 
 	"github.com/hashicorp/terraform/tfdiags"
 
-	"github.com/hashicorp/terraform/internal/logging"
+	_ "github.com/hashicorp/terraform/internal/logging"
 )
 
 func TestMain(m *testing.M) {
 	flag.Parse()
-	if testing.Verbose() {
-		// if we're verbose, use the logging requested by TF_LOG
-		logging.SetOutput()
-	} else {
-		// otherwise silence all logs
-		log.SetOutput(ioutil.Discard)
-	}
-
 	os.Exit(m.Run())
 }
 

dag/walk.go

@@ -383,7 +383,6 @@ func (w *Walker) walkVertex(v Vertex, info *walkerVertex) {
 	var diags tfdiags.Diagnostics
 	var upstreamFailed bool
 	if depsSuccess {
-		log.Printf("[TRACE] dag/walk: visiting %q", VertexName(v))
 		diags = w.Callback(v)
 	} else {
 		log.Printf("[TRACE] dag/walk: upstream of %q errored, so skipping", VertexName(v))

internal/getproviders/http_mirror_source.go

@@ -68,11 +68,7 @@ func newHTTPMirrorSourceWithHTTPClient(baseURL *url.URL, creds svcauth.Credentia
 	retryableClient.RequestLogHook = requestLogHook
 	retryableClient.ErrorHandler = maxRetryErrorHandler
 
-	logOutput, err := logging.LogOutput()
-	if err != nil {
-		log.Printf("[WARN] Failed to set up provider HTTP mirror logger, so continuing without client logging: %s", err)
-	}
-	retryableClient.Logger = log.New(logOutput, "", log.Flags())
+	retryableClient.Logger = log.New(logging.LogOutput(), "", log.Flags())
 
 	return &HTTPMirrorSource{
 		baseURL:    baseURL,

internal/getproviders/registry_client.go

@@ -77,12 +77,7 @@ func newRegistryClient(baseURL *url.URL, creds svcauth.HostCredentials) *registr
 	retryableClient.RequestLogHook = requestLogHook
 	retryableClient.ErrorHandler = maxRetryErrorHandler
 
-	logOutput, err := logging.LogOutput()
-	if err != nil {
-		log.Printf("[WARN] Failed to set up registry client logger, "+
-			"continuing without client logging: %s", err)
-	}
-	retryableClient.Logger = log.New(logOutput, "", log.Flags())
+	retryableClient.Logger = log.New(logging.LogOutput(), "", log.Flags())
 
 	return &registryClient{
 		baseURL:    baseURL,

internal/initwd/module_install_test.go

@@ -4,7 +4,6 @@ import (
 	"flag"
 	"fmt"
 	"io/ioutil"
-	"log"
 	"os"
 	"path/filepath"
 	"strings"
@@ -15,21 +14,14 @@ import (
 	"github.com/hashicorp/terraform/configs"
 	"github.com/hashicorp/terraform/configs/configload"
 	"github.com/hashicorp/terraform/internal/copy"
-	"github.com/hashicorp/terraform/internal/logging"
 	"github.com/hashicorp/terraform/registry"
 	"github.com/hashicorp/terraform/tfdiags"
+
+	_ "github.com/hashicorp/terraform/internal/logging"
 )
 
 func TestMain(m *testing.M) {
 	flag.Parse()
-	if testing.Verbose() {
-		// if we're verbose, use the logging requested by TF_LOG
-		logging.SetOutput()
-	} else {
-		// otherwise silence all logs
-		log.SetOutput(ioutil.Discard)
-	}
-
 	os.Exit(m.Run())
 }
 

internal/logging/logging.go

@@ -25,16 +25,25 @@ var ValidLevels = []LogLevel{"TRACE", "DEBUG", "INFO", "WARN", "ERROR"}
 // logger is the global hclog logger
 var logger hclog.Logger
 
+// logWriter is a global writer for logs, to be used with the std log package
+var logWriter io.Writer
+
 func init() {
 	logger = NewHCLogger("")
+	logWriter = logger.StandardWriter(&hclog.StandardLoggerOptions{InferLevels: true})
+
+	// setup the default std library logger to use our output
+	log.SetFlags(0)
+	log.SetPrefix("")
+	log.SetOutput(logWriter)
 }
 
-// LogOutput determines where we should send logs (if anywhere) and the log level.
-func LogOutput() (logOutput io.Writer, err error) {
-	return logger.StandardWriter(&hclog.StandardLoggerOptions{InferLevels: true}), nil
+// LogOutput return the default global log io.Writer
+func LogOutput() io.Writer {
+	return logWriter
 }
 
-// HCLogger returns the default global loggers
+// HCLogger returns the default global hclog logger
 func HCLogger() hclog.Logger {
 	return logger
 }
@@ -63,25 +72,6 @@ func NewHCLogger(name string) hclog.Logger {
 	})
 }
 
-// SetOutput checks for a log destination with LogOutput, and calls
-// log.SetOutput with the result. If LogOutput returns nil, SetOutput uses
-// ioutil.Discard. Any error from LogOutout is fatal.
-func SetOutput() {
-	out, err := LogOutput()
-	if err != nil {
-		log.Fatal(err)
-	}
-
-	if out == nil {
-		out = ioutil.Discard
-	}
-
-	// the hclog logger will add the prefix info
-	log.SetFlags(0)
-	log.SetPrefix("")
-	log.SetOutput(out)
-}
-
 // CurrentLogLevel returns the current log level string based the environment vars
 func CurrentLogLevel() string {
 	envLevel := strings.ToUpper(os.Getenv(EnvLog))

registry/client.go

@@ -87,11 +87,7 @@ func NewClient(services *disco.Disco, client *http.Client) *Client {
 	retryableClient.RequestLogHook = requestLogHook
 	retryableClient.ErrorHandler = maxRetryErrorHandler
 
-	logOutput, err := logging.LogOutput()
-	if err != nil {
-		log.Printf("[WARN] Failed to set up registry client logger, "+
-			"continuing without client logging: %s", err)
-	}
+	logOutput := logging.LogOutput()
 	retryableClient.Logger = log.New(logOutput, "", log.Flags())
 
 	services.Transport = retryableClient.HTTPClient.Transport

repl/session_test.go

@@ -2,8 +2,6 @@ package repl
 
 import (
 	"flag"
-	"io/ioutil"
-	"log"
 	"os"
 	"strings"
 	"testing"
@@ -13,23 +11,15 @@ import (
 	"github.com/hashicorp/terraform/addrs"
 	"github.com/hashicorp/terraform/configs/configschema"
 	"github.com/hashicorp/terraform/internal/initwd"
-	"github.com/hashicorp/terraform/internal/logging"
 	"github.com/hashicorp/terraform/providers"
 	"github.com/hashicorp/terraform/states"
 	"github.com/hashicorp/terraform/terraform"
+
+	_ "github.com/hashicorp/terraform/internal/logging"
 )
 
 func TestMain(m *testing.M) {
 	flag.Parse()
-
-	if testing.Verbose() {
-		// if we're verbose, use the logging requested by TF_LOG
-		logging.SetOutput()
-	} else {
-		// otherwise silence all logs
-		log.SetOutput(ioutil.Discard)
-	}
-
 	os.Exit(m.Run())
 }
 

states/statemgr/statemgr_test.go

@@ -4,13 +4,11 @@ import (
 	"context"
 	"encoding/json"
 	"flag"
-	"io/ioutil"
-	"log"
 	"os"
 	"testing"
 	"time"
 
-	"github.com/hashicorp/terraform/internal/logging"
+	_ "github.com/hashicorp/terraform/internal/logging"
 )
 
 func TestNewLockInfo(t *testing.T) {
@@ -91,12 +89,5 @@ func TestLockWithContext(t *testing.T) {
 
 func TestMain(m *testing.M) {
 	flag.Parse()
-	if testing.Verbose() {
-		// if we're verbose, use the logging requested by TF_LOG
-		logging.SetOutput()
-	} else {
-		// otherwise silence all logs
-		log.SetOutput(ioutil.Discard)
-	}
 	os.Exit(m.Run())
 }

terraform/context.go

@@ -10,7 +10,6 @@ import (
 	"github.com/hashicorp/terraform/addrs"
 	"github.com/hashicorp/terraform/configs"
 	"github.com/hashicorp/terraform/instances"
-	"github.com/hashicorp/terraform/internal/logging"
 	"github.com/hashicorp/terraform/lang"
 	"github.com/hashicorp/terraform/plans"
 	"github.com/hashicorp/terraform/providers"
@@ -19,11 +18,9 @@ import (
 	"github.com/hashicorp/terraform/states/statefile"
 	"github.com/hashicorp/terraform/tfdiags"
 	"github.com/zclconf/go-cty/cty"
-)
 
-func init() {
-	logging.SetOutput()
-}
+	_ "github.com/hashicorp/terraform/internal/logging"
+)
 
 // InputMode defines what sort of input will be asked for when Input
 // is called on Context.

terraform/graph.go

@@ -2,6 +2,7 @@ package terraform
 
 import (
 	"log"
+	"strings"
 
 	"github.com/hashicorp/terraform/tfdiags"
 
@@ -77,7 +78,11 @@ func (g *Graph) walk(walker GraphWalker) tfdiags.Diagnostics {
 				subDiags := g.walk(walker)
 				diags = diags.Append(subDiags)
 				if subDiags.HasErrors() {
-					log.Printf("[TRACE] vertex %q: dynamic subgraph encountered errors", dag.VertexName(v))
+					var errs []string
+					for _, d := range subDiags {
+						errs = append(errs, d.Description().Summary)
+					}
+					log.Printf("[TRACE] vertex %q: dynamic subgraph encountered errors: %s", dag.VertexName(v), strings.Join(errs, ","))
 					return
 				}
 				log.Printf("[TRACE] vertex %q: dynamic subgraph completed successfully", dag.VertexName(v))

terraform/terraform_test.go

@@ -4,7 +4,6 @@ import (
 	"flag"
 	"io"
 	"io/ioutil"
-	"log"
 	"os"
 	"path/filepath"
 	"strings"
@@ -20,12 +19,13 @@ import (
 	"github.com/hashicorp/terraform/configs/configload"
 	"github.com/hashicorp/terraform/helper/experiment"
 	"github.com/hashicorp/terraform/internal/initwd"
-	"github.com/hashicorp/terraform/internal/logging"
 	"github.com/hashicorp/terraform/plans"
 	"github.com/hashicorp/terraform/providers"
 	"github.com/hashicorp/terraform/provisioners"
 	"github.com/hashicorp/terraform/registry"
 	"github.com/hashicorp/terraform/states"
+
+	_ "github.com/hashicorp/terraform/internal/logging"
 )
 
 // This is the directory where our test fixtures are.
@@ -39,14 +39,6 @@ func TestMain(m *testing.M) {
 	experiment.Flag(flag.CommandLine)
 	flag.Parse()
 
-	if testing.Verbose() {
-		// if we're verbose, use the logging requested by TF_LOG
-		logging.SetOutput()
-	} else {
-		// otherwise silence all logs
-		log.SetOutput(ioutil.Discard)
-	}
-
 	// Make sure shadow operations fail our real tests
 	contextFailOnShadowError = true