add templating & dockerize application #2

2025-08-08T20:42:00Z

jonasclaes commented

2025-08-08 20:42:00 +00:00

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copilot-pull-request-reviewer[bot] (Migrated from github.com) reviewed

2025-08-08 20:42:46 +00:00

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Pull Request Overview

This PR adds templating functionality to the thermal printer application and containerizes it with Docker. The changes enable users to print receipts using template files with variable substitution instead of raw ESC/POS commands.

Adds a templating system with custom functions for formatting (bold, underline, italic)
Introduces a new /print-template API endpoint for template-based printing
Dockerizes the application with proper configuration for containerized deployment

Reviewed Changes

Copilot reviewed 16 out of 17 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
templates/receipt.tmpl	Sample receipt template demonstrating variable substitution and formatting functions
pkg/template/template.go	Core templating engine with ESC/POS rendering functionality
pkg/service/printer-service.go	Service layer method for template printing
pkg/service/print-service.go	Low-level template rendering and printing methods
pkg/dto/printer-dto.go	DTO for template printing requests
pkg/controller/printer-controller.go	HTTP endpoint for template printing
Dockerfile	Multi-stage Docker build with proper security practices
docker-compose.yml	Docker Compose configuration for easy deployment
config.docker.toml	Docker-specific configuration file
pkg/model/app-config.go	Changed default host binding for container compatibility
pkg/escpos/const.go	Extended character code page constants

## Pull Request Overview This PR adds templating functionality to the thermal printer application and containerizes it with Docker. The changes enable users to print receipts using template files with variable substitution instead of raw ESC/POS commands. - Adds a templating system with custom functions for formatting (bold, underline, italic) - Introduces a new `/print-template` API endpoint for template-based printing - Dockerizes the application with proper configuration for containerized deployment ### Reviewed Changes Copilot reviewed 16 out of 17 changed files in this pull request and generated 3 comments. <details> <summary>Show a summary per file</summary> | File | Description | | ---- | ----------- | | templates/receipt.tmpl | Sample receipt template demonstrating variable substitution and formatting functions | | pkg/template/template.go | Core templating engine with ESC/POS rendering functionality | | pkg/service/printer-service.go | Service layer method for template printing | | pkg/service/print-service.go | Low-level template rendering and printing methods | | pkg/dto/printer-dto.go | DTO for template printing requests | | pkg/controller/printer-controller.go | HTTP endpoint for template printing | | Dockerfile | Multi-stage Docker build with proper security practices | | docker-compose.yml | Docker Compose configuration for easy deployment | | config.docker.toml | Docker-specific configuration file | | pkg/model/app-config.go | Changed default host binding for container compatibility | | pkg/escpos/const.go | Extended character code page constants | </details>

Dockerfile

					
				@ -0,0 +50,4 @@

				EXPOSE 8080

				# Health check

				HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \

The health check uses 'wget' but the Alpine image doesn't include wget by default. Consider using 'curl' (which needs to be installed) or a simple approach like 'nc' for port checking, or install wget in the RUN command above.

pkg/template/template.go

					
				@ -0,0 +56,4 @@

						},

						"italics": func(text string) string {

							return fmt.Sprintf("\x1B\x34\x01%s\x1B\x34\x00", text)

						},

The 'italics' function duplicates the exact same logic as the 'italic' function. Consider removing this duplicate or making one an alias of the other to reduce code duplication.

		"italic":   italicFunc,
		"italics":  italicFunc,

The 'italics' function duplicates the exact same logic as the 'italic' function. Consider removing this duplicate or making one an alias of the other to reduce code duplication. ```suggestion "italic": italicFunc, "italics": italicFunc, ```

templates/receipt.tmpl

					
				@ -0,0 +10,4 @@

				{{bold (printf "Subtotal: \xD5%.2f" .subtotal)}}

				{{bold (printf "Tax:      \xD5%.2f" .tax)}}

				{{bold (printf "Total:    \xD5%.2f" .total)}}

The currency symbol '\xD5' is a magic number. Consider making this configurable or using a named constant to improve maintainability and support multiple currencies.

{{range $item, $price := .items}}{{$item}}: {{bold (printf "%s%.2f\n" .currencySymbol $price)}}{{end}}

{{bold (printf "Subtotal: %s%.2f" .currencySymbol .subtotal)}}
{{bold (printf "Tax:      %s%.2f" .currencySymbol .tax)}}
{{bold (printf "Total:    %s%.2f" .currencySymbol .total)}}

The currency symbol '\xD5' is a magic number. Consider making this configurable or using a named constant to improve maintainability and support multiple currencies. ```suggestion {{range $item, $price := .items}}{{$item}}: {{bold (printf "%s%.2f\n" .currencySymbol $price)}}{{end}} {{bold (printf "Subtotal: %s%.2f" .currencySymbol .subtotal)}} {{bold (printf "Tax: %s%.2f" .currencySymbol .tax)}} {{bold (printf "Total: %s%.2f" .currencySymbol .total)}} ```

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