address some of Daniel's comments

docs/DATA_FORMATS_INPUT.md

@@ -726,23 +726,23 @@ HTTPD_ERRORLOG %{HTTPD20_ERRORLOG}|%{HTTPD24_ERRORLOG}
 
 #### Grok Configuration:
 ```toml
-  [inputs.reader]
+[[inputs.reader]]
   ## This is a list of patterns to check the given log file(s) for.
   ## Note that adding patterns here increases processing time. The most
   ## efficient configuration is to have one pattern per logparser.
   ## Other common built-in patterns are:
   ##   %{COMMON_LOG_FORMAT}   (plain apache & nginx access logs)
   ##   %{COMBINED_LOG_FORMAT} (access logs + referrer & agent)
-    patterns = ["%{COMBINED_LOG_FORMAT}"]
+  grok_patterns = ["%{COMBINED_LOG_FORMAT}"]
 
   ## Name of the outputted measurement name.
-    name_override = "apache_access_log"
+  grok_name_override = "apache_access_log"
 
   ## Full path(s) to custom pattern files.
-    custom_pattern_files = []
+  grok_custom_pattern_files = []
 
   ## Custom patterns can also be defined here. Put one pattern per line.
-    custom_patterns = '''
+  grok_custom_patterns = '''
 
   ## Timezone allows you to provide an override for timestamps that
   ## don't already include an offset
@@ -753,5 +753,5 @@ HTTPD_ERRORLOG %{HTTPD20_ERRORLOG}|%{HTTPD24_ERRORLOG}
   ##   1. Local             -- interpret based on machine localtime
   ##   2. "Canada/Eastern"  -- Unix TZ values like those found in https://en.wikipedia.org/wiki/List_of_tz_database_time_zones
   ##   3. UTC               -- or blank/unspecified, will return timestamp in UTC
-    timezone = "Canada/Eastern"
-    ```
+  grok_timezone = "Canada/Eastern"
+```

internal/config/config.go

@@ -1339,7 +1339,7 @@ func buildParser(name string, tbl *ast.Table) (parsers.Parser, error) {
 	}
 
 	//for grok data_format
-	if node, ok := tbl.Fields["named_patterns"]; ok {
+	if node, ok := tbl.Fields["grok_named_patterns"]; ok {
 		if kv, ok := node.(*ast.KeyValue); ok {
 			if ary, ok := kv.Value.(*ast.Array); ok {
 				for _, elem := range ary.Value {
@@ -1351,7 +1351,7 @@ func buildParser(name string, tbl *ast.Table) (parsers.Parser, error) {
 		}
 	}
 
-	if node, ok := tbl.Fields["patterns"]; ok {
+	if node, ok := tbl.Fields["grok_patterns"]; ok {
 		if kv, ok := node.(*ast.KeyValue); ok {
 			if ary, ok := kv.Value.(*ast.Array); ok {
 				for _, elem := range ary.Value {
@@ -1363,7 +1363,7 @@ func buildParser(name string, tbl *ast.Table) (parsers.Parser, error) {
 		}
 	}
 
-	if node, ok := tbl.Fields["custom_patterns"]; ok {
+	if node, ok := tbl.Fields["grok_custom_patterns"]; ok {
 		if kv, ok := node.(*ast.KeyValue); ok {
 			if str, ok := kv.Value.(*ast.String); ok {
 				c.CustomPatterns = str.Value
@@ -1371,7 +1371,7 @@ func buildParser(name string, tbl *ast.Table) (parsers.Parser, error) {
 		}
 	}
 
-	if node, ok := tbl.Fields["custom_pattern_files"]; ok {
+	if node, ok := tbl.Fields["grok_custom_pattern_files"]; ok {
 		if kv, ok := node.(*ast.KeyValue); ok {
 			if ary, ok := kv.Value.(*ast.Array); ok {
 				for _, elem := range ary.Value {
@@ -1383,7 +1383,7 @@ func buildParser(name string, tbl *ast.Table) (parsers.Parser, error) {
 		}
 	}
 
-	if node, ok := tbl.Fields["timezone"]; ok {
+	if node, ok := tbl.Fields["grok_timezone"]; ok {
 		if kv, ok := node.(*ast.KeyValue); ok {
 			if str, ok := kv.Value.(*ast.String); ok {
 				c.TimeZone = str.Value
@@ -1406,11 +1406,11 @@ func buildParser(name string, tbl *ast.Table) (parsers.Parser, error) {
 	delete(tbl.Fields, "dropwizard_time_format")
 	delete(tbl.Fields, "dropwizard_tags_path")
 	delete(tbl.Fields, "dropwizard_tag_paths")
-	delete(tbl.Fields, "named_patterns")
-	delete(tbl.Fields, "patterns")
-	delete(tbl.Fields, "custom_patterns")
-	delete(tbl.Fields, "custom_pattern_files")
-	delete(tbl.Fields, "timezone")
+	delete(tbl.Fields, "grok_named_patterns")
+	delete(tbl.Fields, "grok_patterns")
+	delete(tbl.Fields, "grok_custom_patterns")
+	delete(tbl.Fields, "grok_custom_pattern_files")
+	delete(tbl.Fields, "grok_timezone")
 
 	return parsers.NewParser(c)
 }

plugins/inputs/reader/reader.go

@@ -1,8 +1,8 @@
 package reader
 
 import (
+	"fmt"
 	"io/ioutil"
-	"log"
 
 	"github.com/influxdata/telegraf"
 	"github.com/influxdata/telegraf/internal/globpath"
@@ -50,14 +50,8 @@ func (r *Reader) Gather(acc telegraf.Accumulator) error {
 			return err
 		}
 
-		for i, m := range metrics {
-
-			//error if m is nil
-			if m == nil {
-				log.Printf("E! Metric could not be parsed from: %v, on line %v", k, i)
-				continue
-			}
-			acc.AddFields(m.Name(), m.Fields(), m.Tags())
+		for _, m := range metrics {
+			acc.AddFields(m.Name(), m.Fields(), m.Tags(), m.Time())
 		}
 	}
 	return nil
@@ -67,13 +61,12 @@ func (r *Reader) SetParser(p parsers.Parser) {
 	r.parser = p
 }
 
-func (r *Reader) refreshFilePaths() {
+func (r *Reader) refreshFilePaths() error {
 	var allFiles []string
 	for _, filepath := range r.Filepaths {
 		g, err := globpath.Compile(filepath)
 		if err != nil {
-			log.Printf("E! Error Glob %s failed to compile, %s", filepath, err)
-			continue
+			return fmt.Errorf("E! Error Glob: %v could not be compiled, %s", filepath, err)
 		}
 		files := g.Match()
 
@@ -83,13 +76,13 @@ func (r *Reader) refreshFilePaths() {
 	}
 
 	r.Filenames = allFiles
+	return nil
 }
 
-//requires that Parser has been compiled
 func (r *Reader) readMetric(filename string) ([]telegraf.Metric, error) {
 	fileContents, err := ioutil.ReadFile(filename)
 	if err != nil {
-		log.Printf("E! File could not be opened: %v", filename)
+		return nil, fmt.Errorf("E! Error file: %v could not be read, %s", filename, err)
 	}
 	return r.parser.Parse(fileContents)
 

plugins/parsers/grok/parser.go

@@ -71,7 +71,7 @@ type Parser struct {
 	NamedPatterns      []string
 	CustomPatterns     string
 	CustomPatternFiles []string
-	Measurement        string
+	MetricName         string
 
 	// Timezone is an optional component to help render log dates to
 	// your chosen zone.
@@ -167,10 +167,6 @@ func (p *Parser) Compile() error {
 		p.addCustomPatterns(scanner)
 	}
 
-	if p.Measurement == "" {
-		p.Measurement = "logparser_grok"
-	}
-
 	p.loc, err = time.LoadLocation(p.Timezone)
 	if err != nil {
 		log.Printf("W! improper timezone supplied (%s), setting loc to UTC", p.Timezone)
@@ -348,7 +344,7 @@ func (p *Parser) ParseLine(line string) (telegraf.Metric, error) {
 		return nil, fmt.Errorf("logparser_grok: must have one or more fields")
 	}
 
-	return metric.New(p.Measurement, tags, fields, p.tsModder.tsMod(timestamp))
+	return metric.New(p.MetricName, tags, fields, p.tsModder.tsMod(timestamp))
 }
 
 func (p *Parser) Parse(buf []byte) ([]telegraf.Metric, error) {

plugins/parsers/grok/parser_test.go

@@ -9,7 +9,7 @@ import (
 
 func TestGrokParse(t *testing.T) {
 	parser := Parser{
-		Measurement: "t_met",
+		MetricName: "t_met",
 		Patterns:   []string{"%{COMMON_LOG_FORMAT}"},
 	}
 	parser.Compile()

plugins/parsers/registry.go

@@ -148,7 +148,7 @@ func newGrokParser(metricName string,
 	cPatterns string,
 	cPatternFiles []string, tZone string) (Parser, error) {
 	parser := grok.Parser{
-		Measurement:        metricName,
+		MetricName:         metricName,
 		Patterns:           patterns,
 		NamedPatterns:      nPatterns,
 		CustomPatterns:     cPatterns,