sdk/go: somewhat gross support for opentelemetry

had to copy-paste a lot of the telemetry code into sdk/go/. would love
to just move everything there so it can be shared between the shim, the
Go runtime, and the engine, however it is currently a huge PITA to share
code between all three, because of the way codegen works. saving that
for another day. maybe tomorrow.

Signed-off-by: Alex Suraci <alex@dagger.io>

cmd/codegen/generator/go/generator.go

@@ -56,7 +56,11 @@ func (g *GoGenerator) Generate(ctx context.Context, schema *introspection.Schema
 
 	var overlay fs.FS = mfs
 	if g.Config.ModuleName != "" {
-		overlay = layerfs.New(mfs, &MountedFS{FS: dagger.QueryBuilder, Name: "internal"})
+		overlay = layerfs.New(
+			mfs,
+			&MountedFS{FS: dagger.QueryBuilder, Name: "internal"},
+			&MountedFS{FS: dagger.Telemetry, Name: "internal"},
+		)
 	}
 
 	genSt := &generator.GeneratedState{

cmd/codegen/generator/go/templates/module_interfaces.go

@@ -346,7 +346,7 @@ func (spec *parsedIfaceType) marshalJSONMethodCode() *Statement {
 		BlockFunc(func(g *Group) {
 			g.If(Id("r").Op("==").Nil()).Block(Return(Index().Byte().Parens(Lit(`""`)), Nil()))
 
-			g.List(Id("id"), Id("err")).Op(":=").Id("r").Dot("ID").Call(Qual("context", "Background").Call())
+			g.List(Id("id"), Id("err")).Op(":=").Id("r").Dot("ID").Call(Id("marshalCtx"))
 			g.If(Id("err").Op("!=").Nil()).Block(Return(Nil(), Id("err")))
 			g.Return(Id("json").Dot("Marshal").Call(Id("id")))
 		})

cmd/codegen/generator/go/templates/modules.go

@@ -93,6 +93,12 @@ func (funcs goTemplateFuncs) moduleMainSrc() (string, error) {
 
 	tps := []types.Type{}
 	for _, obj := range objs {
+		// ignore any private definitions, they may be part of the runtime itself
+		// e.g. marshalCtx
+		if !obj.Exported() {
+			continue
+		}
+
 		// check if this is the constructor func, save it for later if so
 		if ok := ps.checkConstructor(obj); ok {
 			continue
@@ -230,58 +236,86 @@ const (
 	mainSrc = `func main() {
 	ctx := context.Background()
 
+	// Direct slog to the new stderr. This is only for dev time debugging, and
+	// runtime errors/warnings.
+	slog.SetDefault(slog.New(slog.NewTextHandler(os.Stderr, &slog.HandlerOptions{
+		Level: slog.LevelWarn,
+	})))
+
+	if err := dispatch(ctx); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(2)
+	}
+}
+
+func dispatch(ctx context.Context) error {
+	ctx = telemetry.InitEmbedded(ctx, resource.NewWithAttributes(
+		semconv.SchemaURL,
+		semconv.ServiceNameKey.String("dagger-go-sdk"),
+		// TODO version?
+	))
+	defer telemetry.Close()
+
+	ctx, span := Tracer().Start(ctx, "Go runtime",
+		trace.WithAttributes(
+			// In effect, the following two attributes hide the exec /runtime span.
+			//
+			// Replace the parent span,
+			attribute.Bool("dagger.io/ui.mask", true),
+			// and only show our children.
+			attribute.Bool("dagger.io/ui.passthrough", true),
+		))
+	defer span.End()
+
+	// A lot of the "work" actually happens when we're marshalling the return
+	// value, which entails getting object IDs, which happens in MarshalJSON,
+	// which has no ctx argument, so we use this lovely global variable.
+	setMarshalContext(ctx)
+
 	fnCall := dag.CurrentFunctionCall()
 	parentName, err := fnCall.ParentName(ctx)
 	if err != nil {
-		fmt.Println(err.Error())
-		os.Exit(2)
+		return fmt.Errorf("get parent name: %w", err)
 	}
 	fnName, err := fnCall.Name(ctx)
 	if err != nil {
-		fmt.Println(err.Error())
-		os.Exit(2)
+		return fmt.Errorf("get fn name: %w", err)
 	}
 	parentJson, err := fnCall.Parent(ctx)
 	if err != nil {
-		fmt.Println(err.Error())
-		os.Exit(2)
+		return fmt.Errorf("get fn parent: %w", err)
 	}
 	fnArgs, err := fnCall.InputArgs(ctx)
 	if err != nil {
-		fmt.Println(err.Error())
-		os.Exit(2)
+		return fmt.Errorf("get fn args: %w", err)
 	}
 
 	inputArgs := map[string][]byte{}
 	for _, fnArg := range fnArgs {
 		argName, err := fnArg.Name(ctx)
 		if err != nil {
-			fmt.Println(err.Error())
-			os.Exit(2)
+			return fmt.Errorf("get fn arg name: %w", err)
 		}
 		argValue, err := fnArg.Value(ctx)
 		if err != nil {
-			fmt.Println(err.Error())
-			os.Exit(2)
+			return fmt.Errorf("get fn arg value: %w", err)
 		}
 		inputArgs[argName] = []byte(argValue)
 	}
 
 	result, err := invoke(ctx, []byte(parentJson), parentName, fnName, inputArgs)
 	if err != nil {
-		fmt.Println(err.Error())
-		os.Exit(2)
+		return fmt.Errorf("invoke: %w", err)
 	}
 	resultBytes, err := json.Marshal(result)
 	if err != nil {
-		fmt.Println(err.Error())
-		os.Exit(2)
+		return fmt.Errorf("marshal: %w", err)
 	}
 	_, err = fnCall.ReturnValue(ctx, JSON(resultBytes))
 	if err != nil {
-		fmt.Println(err.Error())
-		os.Exit(2)
+		return fmt.Errorf("store return value: %w", err)
 	}
+	return nil
 }
 `
 	parentJSONVar  = "parentJSON"

cmd/codegen/generator/go/templates/src/_dagger.gen.go/alias.go.tmpl

@@ -1,15 +1,33 @@
 import (
+  "context"
+	"log/slog"
+
 	"{{.PackageImport}}/internal/dagger"
+
+	"go.opentelemetry.io/otel/trace"
 )
 
 var dag = dagger.Connect()
 
+func Tracer() trace.Tracer {
+	return otel.Tracer("dagger.io/sdk.go")
+}
+
+// used for local MarshalJSON implementations
+var marshalCtx = context.Background()
+
+// called by main()
+func setMarshalContext(ctx context.Context) {
+	marshalCtx = ctx
+	dagger.SetMarshalContext(ctx)
+}
+
 type DaggerObject = dagger.DaggerObject
 
 type ExecError = dagger.ExecError
 
 {{ range .Types }}
-{{ $name := .Name | FormatName }} 
+{{ $name := .Name | FormatName }}
 
 {{ .Description | Comment }}
 type {{ $name }} = dagger.{{ $name }}

cmd/codegen/generator/go/templates/src/_dagger.gen.go/defs.go.tmpl

@@ -1,6 +1,7 @@
 import (
 	"context"
 	"encoding/json"
+	"log/slog"
 	"errors"
 	"fmt"
 	"net"
@@ -14,15 +15,33 @@ import (
 	"github.com/Khan/genqlient/graphql"
 	"github.com/vektah/gqlparser/v2/gqlerror"
 	"go.opentelemetry.io/otel/propagation"
+	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/trace"
 
 {{ if IsModuleCode }}
 	"{{.PackageImport}}/internal/querybuilder"
+	"{{.PackageImport}}/internal/telemetry"
 {{ else }}
 	"{{.PackageImport}}/querybuilder"
+	"{{.PackageImport}}/telemetry"
 {{ end }}
 )
 
+func Tracer() trace.Tracer {
+	return otel.Tracer("dagger.io/sdk.go")
+}
+
+// reassigned at runtime after the span is initialized
+var marshalCtx = context.Background()
+
+{{ if IsModuleCode }}
+// SetMarshalContext is a hack that lets us set the ctx to use for
+// MarshalJSON implementations that get an object's ID.
+func SetMarshalContext(ctx context.Context) {
+	marshalCtx = ctx
+}
+{{ end }}
+
 // assertNotNil panic if the given value is nil.
 // This function is used to validate that input with pointer type are not nil.
 // See https://github.com/dagger/dagger/issues/5696 for more context.

cmd/codegen/generator/go/templates/src/_types/object.go.tmpl

@@ -175,7 +175,7 @@ func (r *{{ $.Name | FormatName }}) XXX_GraphQLID(ctx context.Context) (string,
 }
 
 func (r *{{ $.Name | FormatName }}) MarshalJSON() ([]byte, error) {
-  id, err := r.ID(context.Background())
+  id, err := r.ID(marshalCtx)
   if err != nil {
     return nil, err
   }

go.mod

@@ -13,7 +13,7 @@ require (
 	github.com/a-h/templ v0.2.543
 	github.com/adrg/xdg v0.4.0
 	github.com/blang/semver v3.5.1+incompatible
-	github.com/cenkalti/backoff/v4 v4.2.1
+	github.com/cenkalti/backoff/v4 v4.3.0
 	github.com/charmbracelet/bubbles v0.18.0 // indirect
 	github.com/charmbracelet/bubbletea v0.25.0
 	github.com/charmbracelet/lipgloss v0.9.1
@@ -94,8 +94,8 @@ require (
 	golang.org/x/term v0.17.0
 	golang.org/x/text v0.14.0
 	golang.org/x/tools v0.17.0
-	google.golang.org/grpc v1.62.0
-	google.golang.org/protobuf v1.32.0
+	google.golang.org/grpc v1.62.1
+	google.golang.org/protobuf v1.33.0
 	gopkg.in/yaml.v3 v3.0.1
 	gotest.tools/v3 v3.5.1
 )
@@ -109,7 +109,7 @@ require (
 	go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp v1.24.0
 	go.opentelemetry.io/otel/log v0.0.1-alpha
 	go.opentelemetry.io/otel/sdk/metric v1.24.0
-	google.golang.org/genproto/googleapis/rpc v0.0.0-20240123012728-ef4313101c80
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20240325203815-454cdb8f5daa
 )
 
 require (

go.sum

@@ -269,8 +269,8 @@ github.com/bwesterb/go-ristretto v1.2.3/go.mod h1:fUIoIZaG73pV5biE2Blr2xEzDoMj7N
 github.com/caarlos0/ctrlc v1.0.0/go.mod h1:CdXpj4rmq0q/1Eb44M9zi2nKB0QraNKuRGYGrrHhcQw=
 github.com/campoy/unique v0.0.0-20180121183637-88950e537e7e/go.mod h1:9IOqJGCPMSc6E5ydlp5NIonxObaeu/Iub/X03EKPVYo=
 github.com/cavaliercoder/go-cpio v0.0.0-20180626203310-925f9528c45e/go.mod h1:oDpT4efm8tSYHXV5tHSdRvBet/b/QzxZ+XyyPehvm3A=
-github.com/cenkalti/backoff/v4 v4.2.1 h1:y4OZtCnogmCPw98Zjyt5a6+QwPLGkiQsYW5oUqylYbM=
-github.com/cenkalti/backoff/v4 v4.2.1/go.mod h1:Y3VNntkOUPxTVeUxJ/G5vcM//AlwfmyYozVcomhLiZE=
+github.com/cenkalti/backoff/v4 v4.3.0 h1:MyRJ/UdXutAwSAT+s3wNd7MfTIcy71VQueUuFK343L8=
+github.com/cenkalti/backoff/v4 v4.3.0/go.mod h1:Y3VNntkOUPxTVeUxJ/G5vcM//AlwfmyYozVcomhLiZE=
 github.com/census-instrumentation/opencensus-proto v0.2.0/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
 github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
 github.com/cespare/xxhash v1.1.0/go.mod h1:XrSqR1VqqWfGrhpAt58auRo0WTKS1nRRg3ghfAqPWnc=
@@ -1841,8 +1841,8 @@ google.golang.org/genproto v0.0.0-20240123012728-ef4313101c80 h1:KAeGQVN3M9nD0/b
 google.golang.org/genproto v0.0.0-20240123012728-ef4313101c80/go.mod h1:cc8bqMqtv9gMOr0zHg2Vzff5ULhhL2IXP4sbcn32Dro=
 google.golang.org/genproto/googleapis/api v0.0.0-20240123012728-ef4313101c80 h1:Lj5rbfG876hIAYFjqiJnPHfhXbv+nzTWfm04Fg/XSVU=
 google.golang.org/genproto/googleapis/api v0.0.0-20240123012728-ef4313101c80/go.mod h1:4jWUdICTdgc3Ibxmr8nAJiiLHwQBY0UI0XZcEMaFKaA=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20240123012728-ef4313101c80 h1:AjyfHzEPEFp/NpvfN5g+KDla3EMojjhRVZc1i7cj+oM=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20240123012728-ef4313101c80/go.mod h1:PAREbraiVEVGVdTZsVWjSbbTtSyGbAgIIvni8a8CD5s=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20240325203815-454cdb8f5daa h1:RBgMaUMP+6soRkik4VoN8ojR2nex2TqZwjSSogic+eo=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20240325203815-454cdb8f5daa/go.mod h1:WtryC6hu0hhx87FDGxWCDptyssuo68sk10vYjF+T9fY=
 google.golang.org/grpc v0.0.0-20160317175043-d3ddb4469d5a/go.mod h1:yo6s7OP7yaDglbqo1J04qKzAhqBH6lvTonzMVmEdcZw=
 google.golang.org/grpc v1.14.0/go.mod h1:yo6s7OP7yaDglbqo1J04qKzAhqBH6lvTonzMVmEdcZw=
 google.golang.org/grpc v1.16.0/go.mod h1:0JHn/cJsOMiMfNA9+DeHDlAU7KAAB5GDlYFpa9MZMio=
@@ -1862,8 +1862,8 @@ google.golang.org/grpc v1.29.1/go.mod h1:itym6AZVZYACWQqET3MqgPpjcuV5QH3BxFS3Iji
 google.golang.org/grpc v1.30.0/go.mod h1:N36X2cJ7JwdamYAgDz+s+rVMFjt3numwzf/HckM8pak=
 google.golang.org/grpc v1.31.0/go.mod h1:N36X2cJ7JwdamYAgDz+s+rVMFjt3numwzf/HckM8pak=
 google.golang.org/grpc v1.33.2/go.mod h1:JMHMWHQWaTccqQQlmk3MJZS+GWXOdAesneDmEnv2fbc=
-google.golang.org/grpc v1.62.0 h1:HQKZ/fa1bXkX1oFOvSjmZEUL8wLSaZTjCcLAlmZRtdk=
-google.golang.org/grpc v1.62.0/go.mod h1:IWTG0VlJLCh1SkC58F7np9ka9mx/WNkjl4PGJaiq+QE=
+google.golang.org/grpc v1.62.1 h1:B4n+nfKzOICUXMgyrNd19h/I9oH0L1pizfk1d4zSgTk=
+google.golang.org/grpc v1.62.1/go.mod h1:IWTG0VlJLCh1SkC58F7np9ka9mx/WNkjl4PGJaiq+QE=
 google.golang.org/protobuf v0.0.0-20200109180630-ec00e32a8dfd/go.mod h1:DFci5gLYBciE7Vtevhsrf46CRTquxDuWsQurQQe4oz8=
 google.golang.org/protobuf v0.0.0-20200221191635-4d8936d0db64/go.mod h1:kwYJMbMJ01Woi6D6+Kah6886xMZcty6N08ah7+eCXa0=
 google.golang.org/protobuf v0.0.0-20200228230310-ab0ca4ff8a60/go.mod h1:cfTl7dwQJ+fmap5saPgwCLgHXTUD7jkjRqWcaiX5VyM=
@@ -1877,8 +1877,8 @@ google.golang.org/protobuf v1.25.0/go.mod h1:9JNX74DMeImyA3h4bdi1ymwjUzf21/xIlba
 google.golang.org/protobuf v1.26.0-rc.1/go.mod h1:jlhhOSvTdKEhbULTjvd4ARK9grFBp09yW+WbY/TyQbw=
 google.golang.org/protobuf v1.26.0/go.mod h1:9q0QmTI4eRPtz6boOQmLYwt+qCgq0jsYwAQnmE0givc=
 google.golang.org/protobuf v1.27.1/go.mod h1:9q0QmTI4eRPtz6boOQmLYwt+qCgq0jsYwAQnmE0givc=
-google.golang.org/protobuf v1.32.0 h1:pPC6BG5ex8PDFnkbrGU3EixyhKcQ2aDuBS36lqK/C7I=
-google.golang.org/protobuf v1.32.0/go.mod h1:c6P6GXX6sHbq/GpV6MGZEdwhWPcYBgnhAHhKbcUYpos=
+google.golang.org/protobuf v1.33.0 h1:uNO2rsAINq/JlFpSdYEKIZ0uKD/R9cpdv0T+yoGwGmI=
+google.golang.org/protobuf v1.33.0/go.mod h1:c6P6GXX6sHbq/GpV6MGZEdwhWPcYBgnhAHhKbcUYpos=
 gopkg.in/airbrake/gobrake.v2 v2.0.9/go.mod h1:/h5ZAUhDkGaJfjzjKLSjv6zCL6O0LLBxU4K+aSYdM/U=
 gopkg.in/alecthomas/kingpin.v2 v2.2.6/go.mod h1:FMv+mEhP44yOT+4EoQTLFTRgOQ1FBLkstjWtayDeSgw=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=