Log stderr on errors (#58)

Fixes #32.

Author: lukehoban

provider/pkg/provider/command.go

@@ -113,8 +113,8 @@ func (c *command) run(ctx context.Context, command string, host *provider.HostCl
 
 	stdoutch := make(chan struct{})
 	stderrch := make(chan struct{})
-	go copyOutput(ctx, host, urn, stdouttee, stdoutch)
-	go copyOutput(ctx, host, urn, stderrtee, stderrch)
+	go copyOutput(ctx, host, urn, stdouttee, stdoutch, diag.Debug)
+	go copyOutput(ctx, host, urn, stderrtee, stderrch, diag.Error)
 
 	err = cmd.Start()
 	pid := cmd.Process.Pid
@@ -140,11 +140,11 @@ func (c *command) run(ctx context.Context, command string, host *provider.HostCl
 	return strings.TrimSuffix(stdoutbuf.String(), "\n"), strings.TrimSuffix(stderrbuf.String(), "\n"), id, nil
 }
 
-func copyOutput(ctx context.Context, host *provider.HostClient, urn resource.URN, r io.Reader, doneCh chan<- struct{}) {
+func copyOutput(ctx context.Context, host *provider.HostClient, urn resource.URN, r io.Reader, doneCh chan<- struct{}, severity diag.Severity) {
 	defer close(doneCh)
 	scanner := bufio.NewScanner(r)
 	for scanner.Scan() {
-		err := host.Log(ctx, diag.Debug, urn, scanner.Text())
+		err := host.Log(ctx, severity, urn, scanner.Text())
 		if err != nil {
 			return
 		}

provider/pkg/provider/remotecommand.go

@@ -24,12 +24,12 @@ import (
 	"strings"
 	"time"
 
-	"github.com/pulumi/pulumi/sdk/v3/go/common/util/retry"
-
 	"golang.org/x/crypto/ssh"
 
 	"github.com/pulumi/pulumi/pkg/v3/resource/provider"
+	"github.com/pulumi/pulumi/sdk/v3/go/common/diag"
 	"github.com/pulumi/pulumi/sdk/v3/go/common/resource"
+	"github.com/pulumi/pulumi/sdk/v3/go/common/util/retry"
 )
 
 type remoteconnection struct {
@@ -175,8 +175,8 @@ func (c *remotecommand) run(ctx context.Context, cmd string, host *provider.Host
 
 	stdoutch := make(chan struct{})
 	stderrch := make(chan struct{})
-	go copyOutput(ctx, host, urn, stdouttee, stdoutch)
-	go copyOutput(ctx, host, urn, stderrtee, stderrch)
+	go copyOutput(ctx, host, urn, stdouttee, stdoutch, diag.Debug)
+	go copyOutput(ctx, host, urn, stderrtee, stderrch, diag.Info)
 
 	err = session.Run(cmd)