discovery: add rails service name detector

pkg/collector/corechecks/servicediscovery/module/impl_linux.go

@@ -342,9 +342,6 @@ func (s *discovery) getServiceInfo(proc *process.Process) (*serviceInfo, error)
  return nil, err
  }
 
- contextMap := make(usm.DetectorContextMap)
- contextMap[usm.ServiceProc] = proc
-
  root := kernel.HostProc(strconv.Itoa(int(proc.Pid)), "root")
  lang := language.FindInArgs(exe, cmdline)
  if lang == "" {
@@ -356,6 +353,8 @@ func (s *discovery) getServiceInfo(proc *process.Process) (*serviceInfo, error)
  }
 
  contextMap := make(usm.DetectorContextMap)
+ contextMap[usm.ServiceProc] = proc
+
  fs := usm.NewSubDirFS(root)
  ctx := usm.NewDetectionContext(cmdline, env, fs)
  ctx.Pid = int(proc.Pid)

pkg/collector/corechecks/servicediscovery/usm/ruby.go

@@ -1,11 +1,12 @@
 // Unless explicitly stated otherwise all files in this repository are licensed
 // under the Apache License Version 2.0.
 // This product includes software developed at Datadog (https://www.datadoghq.com/).
-// Copyright 2016-present Datadog, Inc.
+// Copyright 2024-present Datadog, Inc.
 
 package usm
 
 import (
+ "fmt"
  "io"
  "io/fs"
  "regexp"
@@ -35,7 +36,16 @@ func newRailsDetector(ctx DetectionContext) detector {
 // project is created. This file should contain a `module` declaration with the
 // application name.
 func (r railsDetector) detect(_ []string) (ServiceMetadata, bool) {
- proc := r.ctx.contextMap[ServiceProc].(*process.Process)
+ var proc *process.Process
+
+ if procEntry, ok := r.ctx.ContextMap[ServiceProc]; ok {
+ if p, ok := procEntry.(*process.Process); ok {
+ proc = p
+ } else {
+ log.Error("could not get process object in rails detector")
+ }
+ }
+
  cwd, err := proc.Cwd()
  if err != nil {
  log.Debugf("could not get cwd of process: %s", err)
@@ -47,8 +57,9 @@ func (r railsDetector) detect(_ []string) (ServiceMetadata, bool) {
  return ServiceMetadata{}, false
  }
 
- name, ok := r.findRailsApplicationName(absFile)
- if !ok {
+ name, err := r.findRailsApplicationName(absFile)
+ if err != nil {
+ log.Debugf("could not find ruby application name: %s", err)
  return ServiceMetadata{}, false
  }
 
@@ -57,37 +68,33 @@ func (r railsDetector) detect(_ []string) (ServiceMetadata, bool) {
 
 // findRailsApplicationName scans the `config/application.rb` file to find the
 // Rails application name.
-func (r railsDetector) findRailsApplicationName(filename string) (string, bool) {
- log.Debugf("findRailsApplicationName")
+func (r railsDetector) findRailsApplicationName(filename string) (string, error) {
  file, err := r.ctx.fs.Open(filename)
  if err != nil {
- log.Debugf("could not open application.rb")
- return "", false
+ return "", fmt.Errorf("could not open application.rb: %w", err)
  }
  defer file.Close()
 
  reader, err := SizeVerifiedReader(file)
  if err != nil {
- log.Debugf("skipping application.rb (%q): %v", filename, err)
- return "", true
+ return "", fmt.Errorf("skipping application.rb (%q): %w", filename, err)
  }
 
  bytes, err := io.ReadAll(reader)
  if err != nil {
- log.Debugf("unable to read application.rb (%q): %v", filename, err)
- return "", true
+ return "", fmt.Errorf("unable to read application.rb (%q): %w", filename, err)
  }
 
  matches := moduleRegexp.FindSubmatch(bytes)
- if matches != nil {
- return string(matches[1]), true
+ if len(matches) < 2 {
+ // No match found
+ return "", fmt.Errorf("could not find Ruby module name")
  }
 
- // No match found
- return "", false
+ return string(matches[1]), nil
 }
 
-// Converts a PascalCasedWord to a snake_cased_word.
+// railsUnderscore converts a PascalCasedWord to a snake_cased_word.
 // It keeps uppercase acronyms together when converting (e.g. "HTTPServer" -> "http_server").
 func railsUnderscore(pascalCasedWord string) string {
  snake := matchFirstCap.ReplaceAllString(pascalCasedWord, "${1}_${2}")

pkg/collector/corechecks/servicediscovery/usm/ruby_test.go

@@ -1,9 +1,9 @@
 // Unless explicitly stated otherwise all files in this repository are licensed
 // under the Apache License Version 2.0.
 // This product includes software developed at Datadog (https://www.datadoghq.com/).
-// Copyright 2016-present Datadog, Inc.
+// Copyright 2024-present Datadog, Inc.
 
-//go:build !windows
+//go:build linux
 
 package usm