Version v1.1.0

- Add template header and footer support

Makefile

@@ -47,8 +47,7 @@ gitignore:
 .PHONY: lint
 lint:
 	golangci-lint run \
-		--timeout=3m \
-		--exclude-dirs hack
+		--timeout=3m
 
 .INTERMEDIATE: $(DISTFILE:.gz=)
 $(DISTFILE:.gz=): $(BUILDDIR)

README.md

@@ -317,19 +317,70 @@ terraform.io,76.76.21.21
 
 ### Template
 
-Additionally, you can specify your own template for the lookup result for every task separately. The only available variables are `{{host}}` for the host and `{{address}}` for addresses:
+Additionally, you can specify your own template for the lookup result for every task separately. You can also specify a header (i.e., the first line) and a footer (i.e., the last line) for the template. The only available variables are `{{host}}` for the host and `{{address}}` for addresses, and these variables are available only for the body of the template..
 
 ```bash
-$ dns-lookuper -f testdata/lists/1.lst -r template -t "there is {{host}} with address {{address}}"
+$ dns-lookuper -f testdata/lists/1.lst -r template -t "there is {{host}} with address {{address}}" --template-header "hello from the header of the template" --template-footer "hello from the footer of the template"
 ```
 
 Output:
 
 ```text
-there is cloudflare.com with address 104.16.132.229
+hello from the header of the template
 there is cloudflare.com with address 104.16.133.229
-there is cloudflare.com with address 2606:4700::6810:85e5
+there is cloudflare.com with address 104.16.132.229
 there is cloudflare.com with address 2606:4700::6810:84e5
+there is cloudflare.com with address 2606:4700::6810:85e5
 there is hashicorp.com with address 76.76.21.21
 there is terraform.io with address 76.76.21.21
+hello from the footer of the template
+```
+
+Another example for the config file stored in [testdata/config/template.yaml](/testdata/config/template.yaml):
+
+```yaml
+tasks:
+  - files:
+      - ../lists/1.lst
+      - ../lists/2.lst
+    output: '-'
+    format: template
+    mode: ipv4
+    template:
+      header: |
+        welcome to my awesome resolved list header
+        it can be multiline
+      text: "here is {{host}} with address {{address}}"
+      footer: |
+        welcome to my awesome resolved list footer
+        it can be multiline as well
+        byebye!
+```
+
+```bash
+$ dns-lookuper -c testdata/configs/template.yaml
+```
+
+```text
+welcome to my awesome resolved list header
+it can be multiline
+
+here is cloudflare.com with address 104.16.133.229
+here is cloudflare.com with address 104.16.132.229
+here is google.com with address 142.250.150.138
+here is google.com with address 142.250.150.113
+here is google.com with address 142.250.150.102
+here is google.com with address 142.250.150.100
+here is google.com with address 142.250.150.101
+here is google.com with address 142.250.150.139
+here is hashicorp.com with address 76.76.21.21
+here is linked.in with address 108.174.10.24
+here is rpm.releases.hashicorp.com with address 52.222.214.72
+here is rpm.releases.hashicorp.com with address 52.222.214.58
+here is rpm.releases.hashicorp.com with address 52.222.214.125
+here is rpm.releases.hashicorp.com with address 52.222.214.123
+here is terraform.io with address 76.76.21.21
+welcome to my awesome resolved list footer
+it can be multiline as well
+byebye!
 ```

internal/lookuper/config.go

@@ -11,15 +11,17 @@ import (
 )
 
 const (
-	argFile     = "file"
-	argOutput   = "output"
-	argMode     = "mode"
-	argFormat   = "format"
-	argTemplate = "template"
-	argConfig   = "config"
-	argDaemon   = "daemon"
-	argInterval = "interval"
-	argTimeout  = "timeout"
+	argFile           = "file"
+	argOutput         = "output"
+	argMode           = "mode"
+	argFormat         = "format"
+	argTemplateText   = "template-text"
+	argTemplateHeader = "template-header"
+	argTemplateFooter = "template-footer"
+	argConfig         = "config"
+	argDaemon         = "daemon"
+	argInterval       = "interval"
+	argTimeout        = "timeout"
 )
 
 const (
@@ -66,11 +68,17 @@ type daemonSettings struct {
 }
 
 type task struct {
-	Files    []string `json:"files"`
-	Output   string   `json:"output"`
-	Mode     string   `json:"mode"`
-	Format   string   `json:"format"`
-	Template string   `json:"template"`
+	Files    []string  `json:"files"`
+	Output   string    `json:"output"`
+	Mode     string    `json:"mode"`
+	Format   string    `json:"format"`
+	Template *template `json:"template"`
+}
+
+type template struct {
+	Text   string `json:"text"`
+	Header string `json:"header"`
+	Footer string `json:"footer"`
 }
 
 var (
@@ -103,10 +111,20 @@ var (
 			Value:   formatDefault,
 		},
 		&cli.StringFlag{
-			Name:    argTemplate,
-			Usage:   fmt.Sprintf("output template; required with --%s=%s", argFormat, formatTemplate),
+			Name:    argTemplateText,
+			Usage:   fmt.Sprintf("output template text; required with --%s=%s", argFormat, formatTemplate),
 			Aliases: []string{"t"},
-			EnvVars: []string{"DNS_LOOKUPER_TEMPLATE"},
+			EnvVars: []string{"DNS_LOOKUPER_TEMPLATE_TEXT"},
+		},
+		&cli.StringFlag{
+			Name:    argTemplateHeader,
+			Usage:   "output template header",
+			EnvVars: []string{"DNS_LOOKUPER_TEMPLATE_HEADER"},
+		},
+		&cli.StringFlag{
+			Name:    argTemplateFooter,
+			Usage:   "output template footer",
+			EnvVars: []string{"DNS_LOOKUPER_TEMPLATE_FOOTER"},
 		},
 		&cli.StringFlag{
 			Name:    argConfig,
@@ -140,7 +158,7 @@ var (
 	formatEnum     = []string{formatJSON, formatYAML, formatCSV, formatHosts, formatList, formatTemplate}
 	modeEnum       = []string{modeAll, modeIpv4, modeIpv6}
 	argsConfigFile = []string{argConfig}
-	argCmdLine     = []string{argDaemon, argFile, argFormat, argInterval, argMode, argOutput, argTemplate, argTimeout}
+	argCmdLine     = []string{argDaemon, argFile, argFormat, argInterval, argMode, argOutput, argTemplateText, argTemplateFooter, argTemplateHeader, argTimeout}
 )
 
 func newConfig(clictx *cli.Context) (*Config, error) {
@@ -177,11 +195,15 @@ func newConfig(clictx *cli.Context) (*Config, error) {
 
 	} else if cmdLineIsSet(clictx) {
 		singleton := task{
-			Files:    clictx.StringSlice(argFile),
-			Output:   clictx.String(argOutput),
-			Mode:     clictx.String(argMode),
-			Format:   clictx.String(argFormat),
-			Template: clictx.String(argTemplate),
+			Files:  clictx.StringSlice(argFile),
+			Output: clictx.String(argOutput),
+			Mode:   clictx.String(argMode),
+			Format: clictx.String(argFormat),
+			Template: &template{
+				Header: clictx.String(argTemplateHeader),
+				Text:   clictx.String(argTemplateText),
+				Footer: clictx.String(argTemplateFooter),
+			},
 		}
 
 		result.Tasks = append(result.Tasks, singleton)
@@ -259,12 +281,15 @@ func validateTask(t *task, s *settings) error {
 		return fmt.Errorf("unsupported output format %s; valid formats are %s", t.Format, formatEnum)
 	}
 
-	if t.Format == formatTemplate && t.Template == "" {
-		return fmt.Errorf(`you must specify template string (--%[1]s or "%[1]s" key in file) when output format is "%[2]s"`, argTemplate, formatTemplate)
+	if t.Format == formatTemplate && t.Template.Text == "" {
+		return fmt.Errorf(`you must specify template text at least (--%[1]s or template key in file) when output format is "%[2]s"`, argTemplateText, formatTemplate)
 	}
 
-	if t.Format != formatTemplate && t.Template != "" {
-		return fmt.Errorf(`template string allowed only with output format of type "template"`)
+	if t.Format != formatTemplate &&
+		(t.Template.Text != "" ||
+			t.Template.Header != "" ||
+			t.Template.Footer != "") {
+		return fmt.Errorf(`template settings allowed only with output format of type "%s"`, formatTemplate)
 	}
 
 	return nil

internal/lookuper/lookuper.go

@@ -167,7 +167,8 @@ func performTask(t *task, settings *settings) error {
 	case formatYAML:
 		printer.fn = printer.printYAML
 	case formatCSV:
-		printer.fn = printer.printCSV
+		printer.task.Template = templateCSV
+		printer.fn = printer.printTemplate
 	default:
 		return fmt.Errorf(`invalid output format "%s"`, t.Format)
 	}

internal/lookuper/printers.go

@@ -1,7 +1,6 @@
 package lookuper
 
 import (
-	"encoding/csv"
 	"encoding/json"
 	"fmt"
 	"os"
@@ -21,20 +20,32 @@ type printer struct {
 type printerFunc func() error
 
 var (
-	CSVHeaders    = []string{"name", "address"}
-	templateHosts = "{{address}} {{host}}"
+	templateCSV = &template{
+		Header: "name,address",
+		Text:   "{{host}},{{address}}",
+	}
+
+	templateHosts = &template{
+		Text: "{{address}} {{host}}",
+	}
 )
 
 func (p *printer) print() error {
 	return p.fn()
 }
 
 func (p *printer) printTemplate() error {
-	t, err := fasttemplate.NewTemplate(p.task.Template, "{{", "}}")
+	t, err := fasttemplate.NewTemplate(p.task.Template.Text, "{{", "}}")
 	if err != nil {
 		return err
 	}
 
+	if p.task.Template.Header != "" {
+		if _, err := p.file.WriteString(fmt.Sprintln(p.task.Template.Header)); err != nil {
+			return err
+		}
+	}
+
 	for _, response := range p.responseList {
 		for _, address := range response.Addresses {
 			s := t.ExecuteString(map[string]interface{}{
@@ -47,6 +58,12 @@ func (p *printer) printTemplate() error {
 			}
 		}
 	}
+
+	if p.task.Template.Footer != "" {
+		if _, err := p.file.WriteString(fmt.Sprintln(p.task.Template.Footer)); err != nil {
+			return err
+		}
+	}
 	return nil
 }
 
@@ -99,23 +116,3 @@ func (p *printer) printYAML() error {
 
 	return nil
 }
-
-func (p *printer) printCSV() error {
-	encoder := csv.NewWriter(p.file)
-	defer encoder.Flush()
-
-	err := encoder.Write(CSVHeaders)
-	if err != nil {
-		return err
-	}
-
-	for _, response := range p.responseList {
-		for _, address := range response.Addresses {
-			err = encoder.Write([]string{response.Name, address.String()})
-			if err != nil {
-				return err
-			}
-		}
-	}
-	return nil
-}

testdata/configs/template.yaml

@@ -0,0 +1,16 @@
+tasks:
+  - files:
+      - ../lists/1.lst
+      - ../lists/2.lst
+    output: '-'
+    format: template
+    mode: ipv4
+    template:
+      header: |
+        welcome to my awesome resolved list header
+        it can be multiline
+      text: "here is {{host}} with address {{address}}"
+      footer: |
+        welcome to my awesome resolved list footer
+        it can be multiline as well
+        byebye!