From 8c13faf3d8dc845a4cce19bdc3efcecff33a2b58 Mon Sep 17 00:00:00 2001
From: "Michael B. Gale" <mbg@github.com>
Date: Fri, 5 Sep 2025 14:07:15 +0100
Subject: [PATCH] Go: Set log level based on `CODEQL_VERBOSITY`

---
 .../cli/go-autobuilder/go-autobuilder.go      |  2 +
 go/extractor/cli/go-extractor/BUILD.bazel     |  1 +
 go/extractor/cli/go-extractor/go-extractor.go |  3 ++
 go/extractor/util/BUILD.bazel                 |  2 +
 go/extractor/util/logging.go                  | 45 +++++++++++++++++++
 go/extractor/util/logging_test.go             | 33 ++++++++++++++
 6 files changed, 86 insertions(+)
 create mode 100644 go/extractor/util/logging.go
 create mode 100644 go/extractor/util/logging_test.go

diff --git a/go/extractor/cli/go-autobuilder/go-autobuilder.go b/go/extractor/cli/go-autobuilder/go-autobuilder.go
index 1601b5659d33..ae9a478c3674 100644
--- a/go/extractor/cli/go-autobuilder/go-autobuilder.go
+++ b/go/extractor/cli/go-autobuilder/go-autobuilder.go
@@ -623,6 +623,8 @@ func installDependenciesAndBuild() {
 }
 
 func main() {
+	util.SetLogLevel()
+
 	if len(os.Args) == 1 {
 		installDependenciesAndBuild()
 	} else if len(os.Args) == 2 && os.Args[1] == "--identify-environment" {
diff --git a/go/extractor/cli/go-extractor/BUILD.bazel b/go/extractor/cli/go-extractor/BUILD.bazel
index 769e4a7b09bc..ec7cf150f0a6 100644
--- a/go/extractor/cli/go-extractor/BUILD.bazel
+++ b/go/extractor/cli/go-extractor/BUILD.bazel
@@ -11,6 +11,7 @@ go_library(
     deps = [
         "//go/extractor",
         "//go/extractor/diagnostics",
+        "//go/extractor/util",
     ],
 )
 
diff --git a/go/extractor/cli/go-extractor/go-extractor.go b/go/extractor/cli/go-extractor/go-extractor.go
index 425af6cd55d8..72ab3291f3cc 100644
--- a/go/extractor/cli/go-extractor/go-extractor.go
+++ b/go/extractor/cli/go-extractor/go-extractor.go
@@ -10,6 +10,7 @@ import (
 
 	"github.com/github/codeql-go/extractor"
 	"github.com/github/codeql-go/extractor/diagnostics"
+	"github.com/github/codeql-go/extractor/util"
 )
 
 var cpuprofile, memprofile string
@@ -96,6 +97,8 @@ func parseFlags(args []string, mimic bool, extractTests bool) ([]string, []strin
 }
 
 func main() {
+	util.SetLogLevel()
+
 	extractTestsDefault := os.Getenv("CODEQL_EXTRACTOR_GO_OPTION_EXTRACT_TESTS") == "true"
 	buildFlags, patterns, extractTests := parseFlags(os.Args[1:], false, extractTestsDefault)
 
diff --git a/go/extractor/util/BUILD.bazel b/go/extractor/util/BUILD.bazel
index dd294a63a9c1..b8f005378aa2 100644
--- a/go/extractor/util/BUILD.bazel
+++ b/go/extractor/util/BUILD.bazel
@@ -6,6 +6,7 @@ go_library(
     name = "util",
     srcs = [
         "extractvendordirs.go",
+        "logging.go",
         "registryproxy.go",
         "semver.go",
         "util.go",
@@ -18,6 +19,7 @@ go_library(
 go_test(
     name = "util_test",
     srcs = [
+        "logging_test.go",
         "registryproxy_test.go",
         "semver_test.go",
         "util_test.go",
diff --git a/go/extractor/util/logging.go b/go/extractor/util/logging.go
new file mode 100644
index 000000000000..b0919151edfd
--- /dev/null
+++ b/go/extractor/util/logging.go
@@ -0,0 +1,45 @@
+package util
+
+import (
+	"log/slog"
+	"os"
+	"strings"
+)
+
+// Mirrors the verbosity definitions in the CodeQL CLI, which are passed to us
+// in the `CODEQL_VERBOSITY` environment variable.
+type Verbosity string
+
+const (
+	// Only print error messages.
+	Errors Verbosity = "errors"
+	// Print warnings and error messages.
+	Warnings Verbosity = "warnings"
+	// Default verbosity.
+	Progress Verbosity = "progress"
+	// More details of normal operations.
+	Details Verbosity = "progress+"
+	// Debug level set by e.g. the CodeQL Action.
+	Spammy Verbosity = "progress++"
+	// The most detailed.
+	Spammier Verbosity = "progress+++"
+)
+
+func parseLogLevel(value string) slog.Level {
+	value = strings.ToLower(value)
+	if strings.HasPrefix(value, string(Details)) {
+		return slog.LevelDebug
+	} else if value == string(Errors) {
+		return slog.LevelError
+	} else if value == string(Warnings) {
+		return slog.LevelWarn
+	} else {
+		// Default
+		return slog.LevelInfo
+	}
+}
+
+// Sets the log level for the default `slog` logger, based on `CODEQL_VERBOSITY`.
+func SetLogLevel() {
+	slog.SetLogLoggerLevel(parseLogLevel(os.Getenv("CODEQL_VERBOSITY")))
+}
diff --git a/go/extractor/util/logging_test.go b/go/extractor/util/logging_test.go
new file mode 100644
index 000000000000..1409f7b8d9a0
--- /dev/null
+++ b/go/extractor/util/logging_test.go
@@ -0,0 +1,33 @@
+package util
+
+import (
+	"log/slog"
+	"strings"
+	"testing"
+)
+
+func assertLogLevel(t *testing.T, value string, level slog.Level) {
+	actual := parseLogLevel(value)
+	if actual != level {
+		t.Errorf("Expected %s to parse as %s, but got %s", value, level, actual)
+	}
+}
+
+func TestParseLogLevel(t *testing.T) {
+	// Known verbosity levels.
+	assertLogLevel(t, string(Errors), slog.LevelError)
+	assertLogLevel(t, string(Warnings), slog.LevelWarn)
+	assertLogLevel(t, string(Progress), slog.LevelInfo)
+	assertLogLevel(t, string(Details), slog.LevelDebug)
+	assertLogLevel(t, string(Spammy), slog.LevelDebug)
+	assertLogLevel(t, string(Spammier), slog.LevelDebug)
+
+	// Ignore case
+	assertLogLevel(t, strings.ToUpper(string(Spammier)), slog.LevelDebug)
+	assertLogLevel(t, strings.ToUpper(string(Errors)), slog.LevelError)
+
+	// Other values default to LevelInfo
+	assertLogLevel(t, "", slog.LevelInfo)
+	assertLogLevel(t, "unknown", slog.LevelInfo)
+	assertLogLevel(t, "none", slog.LevelInfo)
+}