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feat(provisioner): propagate trace info
If tracing is enabled, propagate the trace information to the terraform provisioner via environment variables. This sets the `TRACEPARENT` environment variable using the default W3C trace propagators. Users can choose to continue the trace by adding new spans in the provisioner by reading from the environment like: ctx := env.ContextWithRemoteSpanContext(context.Background(), os.Environ())
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‎provisioner/terraform/otelenv.go

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package terraform
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import (
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"context"
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"fmt"
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"strings"
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"unicode"
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"go.opentelemetry.io/otel"
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"go.opentelemetry.io/otel/propagation"
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)
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// TODO: replace this with the upstream OTEL env propagation when it is
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// released.
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// envCarrier is a propagation.TextMapCarrier that is used to extract or
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// inject tracing environment variables. This is used with a
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// propagation.TextMapPropagator
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type envCarrier struct {
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Env []string
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}
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var _ propagation.TextMapCarrier = (*envCarrier)(nil)
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func toKey(key string) string {
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key = strings.ToUpper(key)
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key = strings.ReplaceAll(key, "-", "_")
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return strings.Map(func(r rune) rune {
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if unicode.IsLetter(r) || unicode.IsNumber(r) || r == '_' {
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return r
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}
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return -1
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}, key)
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}
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func (c *envCarrier) Set(key, value string) {
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if c == nil {
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return
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}
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key = toKey(key)
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for i, e := range c.Env {
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if strings.HasPrefix(e, key+"=") {
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// don't directly update the slice so we don't modify the slice
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// passed in
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newEnv := make([]string, len(c.Env))
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copy(newEnv, c.Env)
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c.Env = append(newEnv[:i], append([]string{fmt.Sprintf("%s=%s", key, value)}, newEnv[i+1:]...)...)
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return
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}
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}
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c.Env = append(c.Env, fmt.Sprintf("%s=%s", key, value))
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}
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func (c *envCarrier) Get(key string) string {
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// Get not necessary to inject environment variables
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panic("Not implemented")
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}
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func (c *envCarrier) Keys() []string {
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// Keys not necessary to inject environment variables
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panic("Not implemented")
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}
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// otelEnvInject will add add any necessary environment variables for the span
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// found in the Context. If environment variables are already present
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// in `environ` then they will be updated. If no variables are found the
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// new ones will be appended. The new environment will be returned, `environ`
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// will never be modified.
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func otelEnvInject(ctx context.Context, environ []string) []string {
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c := &envCarrier{Env: environ}
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otel.GetTextMapPropagator().Inject(ctx, c)
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return c.Env
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}

‎provisioner/terraform/otelenv_test.go

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package terraform
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import (
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"context"
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"testing"
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"github.com/stretchr/testify/require"
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"go.opentelemetry.io/otel"
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"go.opentelemetry.io/otel/propagation"
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sdktrace "go.opentelemetry.io/otel/sdk/trace"
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"go.opentelemetry.io/otel/trace"
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)
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type testIDGenerator struct{}
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var _ sdktrace.IDGenerator = (*testIDGenerator)(nil)
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func (g *testIDGenerator) NewIDs(ctx context.Context) (trace.TraceID, trace.SpanID) {
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traceID, _ := trace.TraceIDFromHex("60d19e9e9abf2197c1d6d8f93e28ee2a")
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spanID, _ := trace.SpanIDFromHex("a028bd951229a46f")
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return traceID, spanID
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}
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func (g *testIDGenerator) NewSpanID(ctx context.Context, traceID trace.TraceID) trace.SpanID {
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spanID, _ := trace.SpanIDFromHex("a028bd951229a46f")
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return spanID
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}
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func TestOtelEnvInject(t *testing.T) {
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testTraceProvider := sdktrace.NewTracerProvider(
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sdktrace.WithSampler(sdktrace.AlwaysSample()),
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sdktrace.WithIDGenerator(&testIDGenerator{}),
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)
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tracer := testTraceProvider.Tracer("example")
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ctx, span := tracer.Start(context.Background(), "testing")
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defer span.End()
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input := []string{"PATH=/usr/bin:/bin"}
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otel.SetTextMapPropagator(propagation.TraceContext{})
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got := otelEnvInject(ctx, input)
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require.Equal(t, []string{
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"PATH=/usr/bin:/bin",
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"TRACEPARENT=00-60d19e9e9abf2197c1d6d8f93e28ee2a-a028bd951229a46f-01",
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}, got)
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// verify we update rather than append
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input = []string{
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"PATH=/usr/bin:/bin",
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"TRACEPARENT=origTraceParent",
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"TERM=xterm",
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}
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otel.SetTextMapPropagator(propagation.TraceContext{})
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got = otelEnvInject(ctx, input)
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require.Equal(t, []string{
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"PATH=/usr/bin:/bin",
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"TRACEPARENT=00-60d19e9e9abf2197c1d6d8f93e28ee2a-a028bd951229a46f-01",
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"TERM=xterm",
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}, got)
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}

‎provisioner/terraform/provision.go

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Original file line numberDiff line numberDiff line change
@@ -156,6 +156,7 @@ func (s *server) Plan(
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if err != nil {
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return provisionersdk.PlanErrorf("setup env: %s", err)
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}
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env = otelEnvInject(ctx, env)
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vars, err := planVars(request)
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if err != nil {
@@ -208,6 +209,7 @@ func (s *server) Apply(
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if err != nil {
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return provisionersdk.ApplyErrorf("provision env: %s", err)
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}
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env = otelEnvInject(ctx, env)
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resp, err := e.apply(
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ctx, killCtx, env, sess,
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)

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