feat(syntax/stdlib): add base64_decode helper function (#953)

* feat(syntax/stdlib): add `base64_decode` helper function Signed-off-by: hainenber <[email protected]> * doc: correct title for `base64_decode` func ref Signed-off-by: hainenber <[email protected]> * chore: use a generic string for `base64_decode` code example Signed-off-by: hainenber <[email protected]> --------- Signed-off-by: hainenber <[email protected]>
grafana · Jun 7, 2024 · fa02432 · fa02432
1 parent 10da36a
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -73,6 +73,8 @@ Main (unreleased)
 
 - Prefix Faro measurement values with `value_` to align with the latest Faro cloud receiver updates. (@codecapitano)
 
+- Add `base64_decode` to standard library. (@hainenber)
+
 ### Bugfixes
 
 - Fixed an issue with `prometheus.scrape` in which targets that move from one

diff --git a/docs/sources/reference/stdlib/base64_decode.md b/docs/sources/reference/stdlib/base64_decode.md
@@ -0,0 +1,19 @@
+---
+canonical: https://grafana.com/docs/alloy/latest/reference/stdlib/base64_decode/
+description: Learn about base64_decode
+title: base64_decode
+---
+
+# base64_decode
+
+The `base64_decode` function decodes a RFC4648-compliant Base64-encoded string 
+into the original string. 
+
+`base64_decode` fails if the provided string argument contains invalid Base64 data. 
+
+## Examples
+
+```
+> base64_decode("dGFuZ2VyaW5l")
+tangerine
+```
diff --git a/syntax/internal/stdlib/stdlib.go b/syntax/internal/stdlib/stdlib.go
@@ -2,6 +2,7 @@
 package stdlib
 
 import (
+	"encoding/base64"
 	"encoding/json"
 	"fmt"
 	"os"
@@ -93,6 +94,14 @@ var Identifiers = map[string]interface{}{
 		return res, nil
 	},
 
+	"base64_decode": func(in string) (interface{}, error) {
+		decoded, err := base64.StdEncoding.DecodeString(in)
+		if err != nil {
+			return nil, err
+		}
+		return decoded, nil
+	},
+
 	"json_path": func(jsonString string, path string) (interface{}, error) {
 		jsonPathExpr, err := jp.ParseString(path)
 		if err != nil {

diff --git a/syntax/vm/vm_stdlib_test.go b/syntax/vm/vm_stdlib_test.go
@@ -31,6 +31,7 @@ func TestVM_Stdlib(t *testing.T) {
 		{"yaml_decode array float", "yaml_decode(`[0.0, 1.0, 2.0]`)", []interface{}{float64(0), float64(1), float64(2)}},
 		{"yaml_decode nil field", "yaml_decode(`foo: null`)", map[string]interface{}{"foo": nil}},
 		{"yaml_decode nil array element", `yaml_decode("[0, null]")`, []interface{}{0, nil}},
+		{"base64_decode", `base64_decode("Zm9vYmFyMTIzIT8kKiYoKSctPUB+")`, string(`foobar123!?$*&()'-=@~`)},
 	}
 
 	for _, tc := range tt {