Csv header delimiter (#370)

* support optionally setting the header delimiter

* perform type assertion once

* changelog for csv parser: support optionally setting the header delimiter

* update error test cases. add HeaderDelimiter test cases

Author: Joseph Sirianni

CHANGELOG.md

@@ -8,6 +8,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 - File input: Added optional labels for resolved symlink file name and path [PR 364](https://github.com/observIQ/stanza/pull/364)
+- CSV Parser: Added optional configuration field `header_delimiter` [PR 370](https://github.com/observIQ/stanza/pull/370)
 
 ## 1.1.5 - 2021-07-15
 

docs/operators/csv_parser.md

@@ -9,6 +9,7 @@ The `csv_parser` operator parses the string-type field selected by `parse_from`
 | `id`          | `csv_parser`     | A unique identifier for the operator                                                                                                                                                                                                     |
 | `output`      | Next in pipeline | The connected operator(s) that will receive all outbound entries                                                                                                                                                                         |
 | `header`      | required         | A string of delimited field names. The values in the delimited header will be used as keys                                                                                                                                               |
+| `header_delimiter`   | value of delimiter              | A character that will be used as a delimiter for the header. Values `\r` and `\n` cannot be used as a delimiter                                                                                                    |
 | `delimiter`   | `,`              | A character that will be used as a delimiter. Values `\r` and `\n` cannot be used as a delimiter                                                                                                                                         |
 | `parse_from`  | $                | A [field](/docs/types/field.md) that indicates the field to be parsed                                                                                                                                                                    |
 | `parse_to`    | $                | A [field](/docs/types/field.md) that indicates the field to be parsed                                                                                                                                                                    |
@@ -144,6 +145,50 @@ Configuration:
 }
 ```
 
+</td>
+</tr>
+</table>
+
+#### Parse the field `message` with differing delimiters for header and fields
+
+Configuration:
+
+```yaml
+- type: csv_parser
+  parse_from: message
+  delimiter: "+"
+  header_delimiter: ","
+  header: 'id,severity,message'
+```
+
+<table>
+<tr><td> Input record </td> <td> Output record </td></tr>
+<tr>
+<td>
+
+```json
+{
+  "timestamp": "",
+  "record": {
+    "message": "1+debug+\"\"Debug Message\"\""
+  }
+}
+```
+
+</td>
+<td>
+
+```json
+{
+  "timestamp": "",
+  "record": {
+    "id": "1",
+    "severity": "debug",
+    "message": "\"Debug Message\""
+  }
+}
+```
+
 </td>
 </tr>
 </table>

operator/builtin/parser/csv/csv.go

@@ -27,8 +27,9 @@ func NewCSVParserConfig(operatorID string) *CSVParserConfig {
 type CSVParserConfig struct {
 	helper.ParserConfig `yaml:",inline"`
 
-	Header         string `json:"header" yaml:"header"`
-	FieldDelimiter string `json:"delimiter,omitempty" yaml:"delimiter,omitempty"`
+	Header          string `json:"header" yaml:"header"`
+	HeaderDelimiter string `json:"header_delimiter,omitempty" yaml:"header_delimiter,omitempty"`
+	FieldDelimiter  string `json:"delimiter,omitempty" yaml:"delimiter,omitempty"`
 }
 
 // Build will build a csv parser operator.
@@ -52,17 +53,24 @@ func (c CSVParserConfig) Build(context operator.BuildContext) ([]operator.Operat
 
 	fieldDelimiter := []rune(c.FieldDelimiter)[0]
 
-	if !strings.Contains(c.Header, c.FieldDelimiter) {
-		return nil, fmt.Errorf("missing field delimiter in header")
+	if c.HeaderDelimiter == "" {
+		c.HeaderDelimiter = c.FieldDelimiter
 	}
 
-	numFields := len(strings.Split(c.Header, c.FieldDelimiter))
+	headerDelimiter := []rune(c.HeaderDelimiter)[0]
+
+	if !strings.Contains(c.Header, c.HeaderDelimiter) {
+		return nil, fmt.Errorf("missing header delimiter in header")
+	}
+
+	numFields := len(strings.Split(c.Header, c.HeaderDelimiter))
 
 	csvParser := &CSVParser{
-		ParserOperator: parserOperator,
-		header:         c.Header,
-		fieldDelimiter: fieldDelimiter,
-		numFields:      numFields,
+		ParserOperator:  parserOperator,
+		header:          c.Header,
+		headerDelimiter: headerDelimiter,
+		fieldDelimiter:  fieldDelimiter,
+		numFields:       numFields,
 	}
 
 	return []operator.Operator{csvParser}, nil
@@ -71,9 +79,10 @@ func (c CSVParserConfig) Build(context operator.BuildContext) ([]operator.Operat
 // CSVParser is an operator that parses csv in an entry.
 type CSVParser struct {
 	helper.ParserOperator
-	header         string
-	fieldDelimiter rune
-	numFields      int
+	header          string
+	headerDelimiter rune
+	fieldDelimiter  rune
+	numFields       int
 }
 
 // Process will parse an entry for csv.
@@ -84,17 +93,15 @@ func (r *CSVParser) Process(ctx context.Context, entry *entry.Entry) error {
 // parse will parse a value using the supplied csv header.
 func (r *CSVParser) parse(value interface{}) (interface{}, error) {
 	var csvLine string
-	switch value.(type) {
+	switch t := value.(type) {
 	case string:
-		csvLine += value.(string)
+		csvLine += t
 	case []byte:
-		csvLine += string(value.([]byte))
+		csvLine += string(t)
 	default:
 		return nil, fmt.Errorf("type '%T' cannot be parsed as csv", value)
 	}
 
-	delimiterStr := string([]rune{r.fieldDelimiter})
-
 	reader := csvparser.NewReader(strings.NewReader(csvLine))
 	reader.Comma = r.fieldDelimiter
 	reader.FieldsPerRecord = r.numFields
@@ -110,7 +117,7 @@ func (r *CSVParser) parse(value interface{}) (interface{}, error) {
 			return nil, err
 		}
 
-		for i, key := range strings.Split(r.header, delimiterStr) {
+		for i, key := range strings.Split(r.header, string([]rune{r.headerDelimiter})) {
 			parsedValues[key] = record[i]
 		}
 	}

operator/builtin/parser/csv/csv_test.go

@@ -169,6 +169,19 @@ func TestParserCSV(t *testing.T) {
 				"position": "agent",
 			},
 		},
+		{
+			"header-delimiter",
+			func(p *CSVParserConfig) {
+				p.Header = "name+sev+msg"
+				p.HeaderDelimiter = "+"
+			},
+			"stanza,INFO,started agent",
+			map[string]interface{}{
+				"name": "stanza",
+				"sev":  "INFO",
+				"msg":  "started agent",
+			},
+		},
 	}
 
 	for _, tc := range cases {
@@ -270,7 +283,7 @@ func TestBuildParserCSV(t *testing.T) {
 		c.Header = "name"
 		_, err := c.Build(testutil.NewBuildContext(t))
 		require.Error(t, err)
-		require.Contains(t, err.Error(), "missing field delimiter in header")
+		require.Contains(t, err.Error(), "missing header delimiter in header")
 	})
 
 	t.Run("InvalidHeaderFieldWrongDelimiter", func(t *testing.T) {
@@ -286,6 +299,25 @@ func TestBuildParserCSV(t *testing.T) {
 		c.FieldDelimiter = ":"
 		_, err := c.Build(testutil.NewBuildContext(t))
 		require.Error(t, err)
-		require.Contains(t, err.Error(), "missing field delimiter in header")
+		require.Contains(t, err.Error(), "missing header delimiter in header")
+	})
+
+	t.Run("HeaderDelimiter", func(t *testing.T) {
+		c := newBasicCSVParser()
+		c.Header = "name+position+number"
+		c.HeaderDelimiter = "+"
+		c.FieldDelimiter = ":"
+		_, err := c.Build(testutil.NewBuildContext(t))
+		require.NoError(t, err)
+	})
+
+	t.Run("InvalidHeaderDelimiter", func(t *testing.T) {
+		c := newBasicCSVParser()
+		c.Header = "name,position,number"
+		c.HeaderDelimiter = "+"
+		c.FieldDelimiter = ":"
+		_, err := c.Build(testutil.NewBuildContext(t))
+		require.Error(t, err)
+		require.Contains(t, err.Error(), "missing header delimiter in header")
 	})
 }