[chore][pkg/stanza] Clean up csv parser build (open-telemetry#30645)

pkg/stanza/operator/parser/csv/csv.go

@@ -66,9 +66,6 @@ func (c Config) Build(logger *zap.SugaredLogger) (operator.Operator, error) {
  return nil, errors.New("only one of 'ignore_quotes' or 'lazy_quotes' can be true")
  }
 
- fieldDelimiter := []rune(c.FieldDelimiter)[0]
- headerDelimiter := []rune(c.HeaderDelimiter)[0]
-
  if len([]rune(c.FieldDelimiter)) != 1 {
  return nil, fmt.Errorf("invalid 'delimiter': '%s'", c.FieldDelimiter)
  }
@@ -77,36 +74,39 @@ func (c Config) Build(logger *zap.SugaredLogger) (operator.Operator, error) {
  return nil, fmt.Errorf("invalid 'header_delimiter': '%s'", c.HeaderDelimiter)
  }
 
- var headers []string
- switch {
- case c.Header == "" && c.HeaderAttribute == "":
+ if c.Header == "" && c.HeaderAttribute == "" {
  return nil, errors.New("missing required field 'header' or 'header_attribute'")
- case c.Header != "" && c.HeaderAttribute != "":
+ }
+
+ if c.Header != "" && c.HeaderAttribute != "" {
  return nil, errors.New("only one header parameter can be set: 'header' or 'header_attribute'")
- case c.Header != "" && !strings.Contains(c.Header, c.HeaderDelimiter):
+ }
+
+ if c.Header != "" && !strings.Contains(c.Header, c.HeaderDelimiter) {
  return nil, errors.New("missing field delimiter in header")
- case c.Header != "":
- headers = strings.Split(c.Header, c.HeaderDelimiter)
  }
 
- return &Parser{
+ p := &Parser{
  ParserOperator: parserOperator,
- header: headers,
  headerAttribute: c.HeaderAttribute,
- fieldDelimiter: fieldDelimiter,
- headerDelimiter: headerDelimiter,
+ fieldDelimiter: []rune(c.FieldDelimiter)[0],
+ headerDelimiter: []rune(c.HeaderDelimiter)[0],
  lazyQuotes: c.LazyQuotes,
  ignoreQuotes: c.IgnoreQuotes,
- parse: generateParseFunc(headers, fieldDelimiter, c.LazyQuotes, c.IgnoreQuotes),
- }, nil
+ }
+
+ if c.Header != "" {
+ p.parse = generateParseFunc(strings.Split(c.Header, c.HeaderDelimiter), p.fieldDelimiter, c.LazyQuotes, c.IgnoreQuotes)
+ }
+
+ return p, nil
 }
 
 // Parser is an operator that parses csv in an entry.
 type Parser struct {
  helper.ParserOperator
  fieldDelimiter rune
  headerDelimiter rune
- header []string
  headerAttribute string
  lazyQuotes bool
  ignoreQuotes bool
@@ -117,26 +117,26 @@ type parseFunc func(any) (any, error)
 
 // Process will parse an entry for csv.
 func (r *Parser) Process(ctx context.Context, e *entry.Entry) error {
- parse := r.parse
-
- // If we have a headerAttribute set we need to dynamically generate our parser function
- if r.headerAttribute != "" {
- h, ok := e.Attributes[r.headerAttribute]
- if !ok {
- err := fmt.Errorf("failed to read dynamic header attribute %s", r.headerAttribute)
- r.Error(err)
- return err
- }
- headerString, ok := h.(string)
- if !ok {
- err := fmt.Errorf("header is expected to be a string but is %T", h)
- r.Error(err)
- return err
- }
- headers := strings.Split(headerString, string([]rune{r.headerDelimiter}))
- parse = generateParseFunc(headers, r.fieldDelimiter, r.lazyQuotes, r.ignoreQuotes)
+ // Static parse function
+ if r.parse != nil {
+ return r.ParserOperator.ProcessWith(ctx, e, r.parse)
  }
 
+ // Dynamically generate the parse function based on a header attribute
+ h, ok := e.Attributes[r.headerAttribute]
+ if !ok {
+ err := fmt.Errorf("failed to read dynamic header attribute %s", r.headerAttribute)
+ r.Error(err)
+ return err
+ }
+ headerString, ok := h.(string)
+ if !ok {
+ err := fmt.Errorf("header is expected to be a string but is %T", h)
+ r.Error(err)
+ return err
+ }
+ headers := strings.Split(headerString, string([]rune{r.headerDelimiter}))
+ parse := generateParseFunc(headers, r.fieldDelimiter, r.lazyQuotes, r.ignoreQuotes)
  return r.ParserOperator.ProcessWith(ctx, e, parse)
 }