From d018e6ebbd2b9082253dccd3ca6f57ae7d8fb1a1 Mon Sep 17 00:00:00 2001
From: Paschalis Tsilias <tpaschalis@users.noreply.github.com>
Date: Thu, 23 May 2024 11:55:31 +0200
Subject: [PATCH] otelcol: decouple otel/alloy component IDs (#882)

Signed-off-by: Paschalis Tsilias <paschalist0@gmail.com>
---
 CHANGELOG.md                                  |  3 ++
 internal/component/otelcol/auth/auth.go       | 20 ++++++++++++-
 internal/component/otelcol/auth/auth_test.go  | 30 +++++++++++++++++++
 .../otelcol/receiver/prometheus/prometheus.go |  6 ----
 4 files changed, 52 insertions(+), 7 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index d4d91b324a..6aae180841 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -41,6 +41,9 @@ Main (unreleased)
 
 - Fix error on boot when using IPv6 advertise addresses without explicitly
   specifying a port. (@matthewpi)
+  
+- Fix an issue where having long component labels (>63 chars) on otelcol.auth
+  components lead to a panic. (@tpaschalis)
 
 ### Other changes
 
diff --git a/internal/component/otelcol/auth/auth.go b/internal/component/otelcol/auth/auth.go
index 0281db889c..a404962806 100644
--- a/internal/component/otelcol/auth/auth.go
+++ b/internal/component/otelcol/auth/auth.go
@@ -7,6 +7,8 @@ package auth
 
 import (
 	"context"
+	"fmt"
+	"hash/fnv"
 	"os"
 	"strings"
 
@@ -168,7 +170,7 @@ func (a *Auth) Update(args component.Arguments) error {
 		components = append(components, ext)
 	}
 
-	cTypeStr := strings.ReplaceAll(strings.ReplaceAll(a.opts.ID, ".", "_"), "/", "_")
+	cTypeStr := NormalizeType(a.opts.ID)
 
 	// Inform listeners that our handler changed.
 	a.opts.OnStateChange(Exports{
@@ -187,3 +189,19 @@ func (a *Auth) Update(args component.Arguments) error {
 func (a *Auth) CurrentHealth() component.Health {
 	return a.sched.CurrentHealth()
 }
+
+func getHash(in string) string {
+	fnvHash := fnv.New32()
+	fnvHash.Write([]byte(in))
+	return fmt.Sprintf("%x", fnvHash.Sum(nil))
+}
+
+func NormalizeType(in string) string {
+	res := strings.ReplaceAll(strings.ReplaceAll(in, ".", "_"), "/", "_")
+
+	if len(res) > 63 {
+		res = res[:40] + getHash(res)
+	}
+
+	return res
+}
diff --git a/internal/component/otelcol/auth/auth_test.go b/internal/component/otelcol/auth/auth_test.go
index 464e659f45..8659c31013 100644
--- a/internal/component/otelcol/auth/auth_test.go
+++ b/internal/component/otelcol/auth/auth_test.go
@@ -2,6 +2,7 @@ package auth_test
 
 import (
 	"context"
+	"regexp"
 	"testing"
 	"time"
 
@@ -93,3 +94,32 @@ func (fa fakeAuthArgs) Extensions() map[otelcomponent.ID]otelextension.Extension
 func (fa fakeAuthArgs) Exporters() map[otelcomponent.DataType]map[otelcomponent.ID]otelcomponent.Component {
 	return nil
 }
+
+func TestNormalizeType(t *testing.T) {
+	type tc struct {
+		input    string
+		expected string
+	}
+	testcases := []tc{
+		{"foo", "foo"},
+		{"foo1", "foo1"},
+		{"fooBar", "fooBar"},
+
+		{"foo.bar", "foo_bar"},
+		{"foo/bar", "foo_bar"},
+		{"foo.bar/baz", "foo_bar_baz"},
+		{"foo/bar_baz", "foo_bar_baz"},
+
+		{"thisStringsConstructedSoThatItsLengthIsSetToBeAtSixtyThreeChars", "thisStringsConstructedSoThatItsLengthIsSetToBeAtSixtyThreeChars"},
+		{"whileThisOneHeresConstructedSoThatItsSizeIsEqualToSixtyFourChars", "whileThisOneHeresConstructedSoThatItsSiz2d7fa5d2"},
+	}
+
+	// https://github.com/open-telemetry/opentelemetry-collector/blob/e09b25f7d1b4090a9b7b73ef7d3c514592331554/component/config.go#L127-L131
+	var typeRegexp = regexp.MustCompile(`^[a-zA-Z][0-9a-zA-Z_]{0,62}$`)
+
+	for _, tt := range testcases {
+		actual := auth.NormalizeType(tt.input)
+		require.Equal(t, tt.expected, actual)
+		require.True(t, typeRegexp.MatchString(actual))
+	}
+}
diff --git a/internal/component/otelcol/receiver/prometheus/prometheus.go b/internal/component/otelcol/receiver/prometheus/prometheus.go
index c429405d9e..89775aaa78 100644
--- a/internal/component/otelcol/receiver/prometheus/prometheus.go
+++ b/internal/component/otelcol/receiver/prometheus/prometheus.go
@@ -5,7 +5,6 @@ import (
 	"context"
 	"os"
 	"regexp"
-	"strings"
 	"sync"
 	"time"
 
@@ -117,12 +116,7 @@ func (c *Component) Update(newConfig component.Arguments) error {
 		gcInterval = 5 * time.Minute
 	)
 
-	cTypeStr := strings.ReplaceAll(strings.ReplaceAll(c.opts.ID, ".", "_"), "/", "_")
-
 	settings := otelreceiver.CreateSettings{
-
-		ID: otelcomponent.NewID(otelcomponent.MustNewType(cTypeStr)),
-
 		TelemetrySettings: otelcomponent.TelemetrySettings{
 			Logger: zapadapter.New(c.opts.Logger),