[pkg/stanza] Fix issue where add operator did not correctly compile e…

…xpressions (#26467)

Alternate to #26374

Resolves #26373

.chloggen/pkg-stanza-fix-add.yaml

@@ -0,0 +1,27 @@
+ # Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: filelogreceiver
+
+# A brief description of the change. Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Fix the behavior of the add operator to continue to support EXPR(env("MY_ENV_VAR")) expressions
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [26373]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: []

pkg/stanza/operator/helper/expr_string.go

@@ -91,6 +91,10 @@ func (e ExprStringConfig) Build() (*ExprString, error) {
  }, nil
 }
 
+func ExprCompile(input string) (*vm.Program, error) {
+ return expr.Compile(input, expr.AllowUndefinedVariables(), expr.Patch(&patcher{}))
+}
+
 func ExprCompileBool(input string) (*vm.Program, error) {
  return expr.Compile(input, expr.AllowUndefinedVariables(), expr.Patch(&patcher{}), expr.AsBool())
 }

pkg/stanza/operator/transformer/add/add.go

@@ -8,7 +8,6 @@ import (
  "fmt"
  "strings"
 
- "github.com/antonmedv/expr"
  "github.com/antonmedv/expr/vm"
  "go.uber.org/zap"
 
@@ -61,7 +60,7 @@ func (c Config) Build(logger *zap.SugaredLogger) (operator.Operator, error) {
  exprStr := strings.TrimPrefix(strVal, "EXPR(")
  exprStr = strings.TrimSuffix(exprStr, ")")
 
- compiled, err := expr.Compile(exprStr, expr.AllowUndefinedVariables())
+ compiled, err := helper.ExprCompile(exprStr)
  if err != nil {
  return nil, fmt.Errorf("failed to compile expression '%s': %w", c.IfExpr, err)
  }

pkg/stanza/operator/transformer/add/add_test.go

@@ -23,6 +23,7 @@ type testCase struct {
 }
 
 func TestProcessAndBuild(t *testing.T) {
+ t.Setenv("TEST_EXPR_STRING_ENV", "val")
  now := time.Now()
  newTestEntry := func() *entry.Entry {
  e := entry.New()
@@ -297,6 +298,42 @@ func TestProcessAndBuild(t *testing.T) {
  },
  false,
  },
+ {
+ "add_expr",
+ func() *Config {
+ cfg := NewConfig()
+ cfg.Field = entry.NewAttributeField("fookey")
+ cfg.Value = "EXPR('foo_' + body.key)"
+ return cfg
+ }(),
+ newTestEntry,
+ func() *entry.Entry {
+ e := newTestEntry()
+ e.Attributes = map[string]interface{}{
+ "fookey": "foo_val",
+ }
+ return e
+ },
+ false,
+ },
+ {
+ "add_expr_env",
+ func() *Config {
+ cfg := NewConfig()
+ cfg.Field = entry.NewAttributeField("fookey")
+ cfg.Value = "EXPR('foo_' + env('TEST_EXPR_STRING_ENV'))"
+ return cfg
+ }(),
+ newTestEntry,
+ func() *entry.Entry {
+ e := newTestEntry()
+ e.Attributes = map[string]interface{}{
+ "fookey": "foo_val",
+ }
+ return e
+ },
+ false,
+ },
  }
  for _, tc := range cases {
  t.Run("BuildandProcess/"+tc.name, func(t *testing.T) {