Implement logging telemetry log 1926

[pmoogi-redhat]

Description

Story
As a member of the OpenShift Logging Team, I want telemetry metrics of the CLO
so that we have a better understanding of how CLF is being utilized by customers (e.g. which outputs)

Acceptance Criteria
Verifying telemetry metrics are available from the CLO metrics endpoint in prometheus

/cc @jcantrill @alanconway
/assign

Links

• JIRA: https://issues.redhat.com/browse/LOG-1926

[pmoogi-redhat]

/test functional

[alanconway]

Global variable is not good practice, make this a member of the reconciler or some other suitable home.

[pmoogi-redhat]

@alanconway i see that EO also implemented by declaring global variables part of their metrics package. i wanted to do minimal changes to existing CLO stack and keep all new changes / implementation confining to this telemetry package. do you still think we should make this data a member of reconciler ? let me know.

[alanconway]

IMO this is a concurrent-unsafe pattern. Even if it is implemented safely today it is much too easy for someone who doesn't understand the concurrency rules to make an unsafe reference in new code.

Lets leave it global but use a concurrent-safe map for now. Patch below for a concurrent-safe string map.
I'd like to review the pattern in future, but for now that should do the trick.

diff --git a/internal/utils/stringmap.go b/internal/utils/stringmap.go
new file mode 100644
index 000000000..de1e10bc9
--- /dev/null
+++ b/internal/utils/stringmap.go
@@ -0,0 +1,28 @@
+package utils
+
+import "sync"
+
+// StringMap is a concurrent-safe map[string]string based on sync.Map
+type StringMap struct{ m sync.Map }
+
+// GetOK returns (value, true) if key is present and ("", false) if absent.
+func (m *StringMap) GetOK(key string) (s string, ok bool) {
+	x, ok := m.m.Load(key)
+	if ok {
+		s = x.(string)
+	}
+	return s, ok
+}
+
+// Get returns the value, or "" if the key is absent.
+func (m *StringMap) Get(key string) string {
+	if s, ok := m.GetOK(key); ok == true {
+		return s
+	}
+	return ""
+}
+
+// Set sets key to value.
+func (m *StringMap) Set(key, value string) {
+	m.m.Store(key, value)
+}
diff --git a/internal/utils/stringmap_test.go b/internal/utils/stringmap_test.go
new file mode 100644
index 000000000..ed008f6c7
--- /dev/null
+++ b/internal/utils/stringmap_test.go
@@ -0,0 +1,20 @@
+package utils
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestStringMap(t *testing.T) {
+	m := StringMap{}
+	assert.Equal(t, "", m.Get("x"))
+	s, ok := m.GetOK("x")
+	assert.Equal(t, "", s)
+	assert.False(t, ok)
+	m.Set("x", "y")
+	assert.Equal(t, "y", m.Get("x"))
+	s, ok = m.GetOK("x")
+	assert.Equal(t, "y", s)
+	assert.True(t, ok)
+}

[pmoogi-redhat]

@alanconway resolved

[pmoogi-redhat]

/test e2e

[pmoogi-redhat]

/test e2e

[pmoogi-redhat]

/test e2e

[pmoogi-redhat]

/test e2e

[pmoogi-redhat]

/test e2e

[openshift-ci]

@pmoogi-redhat: all tests passed!

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[alanconway]

/lgtm

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: alanconway, pmoogi-redhat

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