From 5b8c8c2ebd3d12b225ba5e1862f5af4b75bc1748 Mon Sep 17 00:00:00 2001
From: Lukasz Mierzwa <lukasz@cloudflare.com>
Date: Fri, 9 Aug 2024 09:46:01 +0100
Subject: [PATCH] Validate ignoreLabelsValue

---
 docs/changelog.md                |  6 ++++++
 docs/checks/promql/series.md     | 29 +++++++++++++++++++++++++++++
 internal/checks/promql_series.go |  6 ++++++
 internal/config/config_test.go   | 16 ++++++++++++++++
 4 files changed, 57 insertions(+)

diff --git a/docs/changelog.md b/docs/changelog.md
index 7094093c..e53623b8 100644
--- a/docs/changelog.md
+++ b/docs/changelog.md
@@ -1,5 +1,11 @@
 # Changelog
 
+## v0.64.1
+
+### Fixed
+
+- Validate `ignoreLabelsValue` option values in the pint config.
+
 ## v0.64.0
 
 ### Added
diff --git a/docs/checks/promql/series.md b/docs/checks/promql/series.md
index c4caac16..3d43f53d 100644
--- a/docs/checks/promql/series.md
+++ b/docs/checks/promql/series.md
@@ -164,6 +164,8 @@ check "promql/series" {
   should **NOT** report problems if there's a query that uses a **value** that does not exist.
   This can be also set per rule using `# pint rule/set promql/series ignore/label-value $labelName`
   comments, see below.
+  The value of this option is a map where the key is a metric selector to match on and the value
+  is the list of label names.
 
 Example:
 
@@ -193,6 +195,33 @@ check "promql/series" {
 }
 ```
 
+You can use any metric selectors as keys in `ignoreLabelsValue` if you want apply it only
+to metric selectors in queries that match the selector in `ignoreLabelsValue`.
+For example if you have a rule that uses the same metric with two different selectors:
+
+```yaml
+- alerts: ...
+  expr: |
+    rate(http_requests_total{env="prod", code="401"}[5m]) > 0
+    or
+    rate(http_requests_total{env="dev", code="401"}[5m]) > 0
+```
+
+And you want to disable pint warnings only for the second selector (`http_requests_total{env="dev", code="401"}`)
+but not the first one (`http_requests_total{env="prod", code="401"}`) you can do that by adding any label matcher
+used in the query:
+
+```js
+check "promql/series" {
+  ignoreLabelsValue = {
+    "http_requests_total{env=\"dev\"}" = [ "code" ]
+  }
+}
+```
+
+You can only use label matchers that would match the selector from the query itself, not from the time series
+the query would return. This whole logic applies only to the query, not to the results of it.
+
 ### min-age
 
 But default this check will report a problem if a metric was present
diff --git a/internal/checks/promql_series.go b/internal/checks/promql_series.go
index a832a387..7c76a50d 100644
--- a/internal/checks/promql_series.go
+++ b/internal/checks/promql_series.go
@@ -60,6 +60,12 @@ func (c *PromqlSeriesSettings) Validate() error {
 		c.lookbackStepDuration = time.Duration(dur)
 	}
 
+	for selector := range c.IgnoreLabelsValue {
+		if _, err := promParser.ParseMetricSelector(selector); err != nil {
+			return fmt.Errorf("%q is not a valid PromQL metric selector: %w", selector, err)
+		}
+	}
+
 	return nil
 }
 
diff --git a/internal/config/config_test.go b/internal/config/config_test.go
index cb39a4b1..3e2fb757 100644
--- a/internal/config/config_test.go
+++ b/internal/config/config_test.go
@@ -2148,6 +2148,22 @@ func TestConfigErrors(t *testing.T) {
 			config: `check "promql/series" { ignoreMetrics = [".+++"] }`,
 			err:    "error parsing regexp: invalid nested repetition operator: `++`",
 		},
+		{
+			config: `check "promql/series" {
+  ignoreLabelsValue = {
+    "foo bar" = [ "abc" ]
+  }
+}`,
+			err: `"foo bar" is not a valid PromQL metric selector: 1:5: parse error: unexpected identifier "bar"`,
+		},
+		{
+			config: `check "promql/series" {
+  ignoreLabelsValue = {
+    "foo{" = [ "abc" ]
+  }
+}`,
+			err: `"foo{" is not a valid PromQL metric selector: 1:5: parse error: unexpected end of input inside braces`,
+		},
 		{
 			config: `rule {
   link ".+++" {}