feat(flags): adds support for http proxy config (#82)

Reviewed-on: https://codeberg.org/woodpecker-plugins/go-plugin/pulls/82
Reviewed-by: qwerty287 <qwerty287@noreply.codeberg.org>
Co-authored-by: OCram85 <marco.blessing@googlemail.com>
Co-committed-by: OCram85 <marco.blessing@googlemail.com>

README.md

@@ -9,12 +9,40 @@ HTTP client library.
 ## Builtin settings
 
 | Settings Name | Environment variable | Default | Description                                                                  |
-| ------------- | -------------------- | ------- | ---------------------------------------------------------------------------- | ------------------------------------ |
+| ------------- | -------------------- | ------- | ---------------------------------------------------------------------------- |
 | `log_level`   | -                    | `info`  | Sets log level (`panic`, `fatal`, `error`, `warn`, `info`, `debug`, `trace`) |
-| `skip_verify` | -                    | `false` | -                                                                            | Skip verification of TLS certificate |
+| `skip_verify` | -                    | `false` | Skip verification of TLS certificate                                         |
 |               | `SOCKS_PROXY`        | _none_  | SOCKS5 proxy to use for connections                                          |
 |               | `SOCKS_PROXY_OFF`    | _none_  | Do not use SOCKS5 proxy                                                      |
 
+### Optional: HTTP proxy support
+
+HTTP proxy support is **opt-in** and must be explicitly enabled by the plugin author via `EnableHTTPProxy: true` in `plugin.Options`. When enabled, the following settings become available:
+
+| Settings Name | Environment variable | Default | Description                                            |
+| ------------- | -------------------- | ------- | ------------------------------------------------------ |
+| `http_proxy`  | `HTTP_PROXY`         | _none_  | HTTP proxy URL for outgoing connections                |
+| `https_proxy` | `HTTPS_PROXY`        | _none_  | HTTPS proxy URL for outgoing connections               |
+| `no_proxy`    | `NO_PROXY`           | _none_  | Comma-separated list of hosts to exclude from proxying |
+
+The settings are resolved in the following order of precedence:
+
+1. **Plugin settings** — `PLUGIN_HTTP_PROXY`, `PLUGIN_HTTPS_PROXY`, `PLUGIN_NO_PROXY`
+2. **Lowercase env vars** — `http_proxy`, `https_proxy`, `no_proxy`
+3. **Uppercase env vars** — `HTTP_PROXY`, `HTTPS_PROXY`, `NO_PROXY`
+
+Example Woodpecker CI pipeline configuration:
+
+```yaml
+steps:
+  - name: my-plugin
+    image: my-plugin:latest
+    settings:
+      http_proxy: http://proxy.example.com:3128
+      https_proxy: http://proxy.example.com:3128
+      no_proxy: "localhost,internal.example.com"
+```
+
 ## Creating plugin
 
 ```go
@@ -62,10 +90,11 @@ func main() {
 	}
 
 	p.Plugin = plugin.New(plugin.Options{
-		Name:        "sample-plugin",
-		Description: "Sample plugin",
-		Flags:       p.Flags(),
-		Execute:     p.Execute,
+		Name:            "sample-plugin",
+		Description:     "Sample plugin",
+		Flags:           p.Flags(),
+		Execute:         p.Execute,
+		EnableHTTPProxy: true, // opt-in to HTTP proxy support
 	})
 
 	p.Run()

http.go

@@ -20,6 +20,7 @@ import (
 	"crypto/x509"
 	"net"
 	"net/http"
+	"os"
 	"time"
 
 	"github.com/rs/zerolog/log"
@@ -55,13 +56,60 @@ func httpClientFlags() []cli.Flag {
 	}
 }
 
-func HTTPClientFromContext(c *cli.Command) *http.Client {
+// httpProxyFlags returns the optional HTTP proxy flags.
+// Only added to the app when EnableHTTPProxy is set in Options.
+func httpProxyFlags() []cli.Flag {
+	return []cli.Flag{
+		&cli.StringFlag{
+			Name:  "transport.http-proxy",
+			Usage: "HTTP proxy URL",
+			Sources: cli.EnvVars(
+				"PLUGIN_HTTP_PROXY",
+			),
+			Hidden: true,
+		},
+		&cli.StringFlag{
+			Name:  "transport.https-proxy",
+			Usage: "HTTPS proxy URL",
+			Sources: cli.EnvVars(
+				"PLUGIN_HTTPS_PROXY",
+			),
+			Hidden: true,
+		},
+		&cli.StringFlag{
+			Name:  "transport.no-proxy",
+			Usage: "Hosts to exclude from proxy (comma-separated)",
+			Sources: cli.EnvVars(
+				"PLUGIN_NO_PROXY",
+			),
+			Hidden: true,
+		},
+	}
+}
+
+func HTTPClientFromContext(c *cli.Command, httpProxyEnabled bool) *http.Client {
 	var (
 		skip     = c.Bool("transport.skip-verify")
 		socks    = c.String("transport.socks-proxy")
 		socksOff = c.Bool("transport.socks-proxy-off")
 	)
 
+	if httpProxyEnabled {
+		if v := c.String("transport.http-proxy"); v != "" {
+			os.Setenv("HTTP_PROXY", v)
+			os.Setenv("http_proxy", v)
+		}
+		if v := c.String("transport.https-proxy"); v != "" {
+			os.Setenv("HTTPS_PROXY", v)
+			os.Setenv("https_proxy", v)
+
+		}
+		if v := c.String("transport.no-proxy"); v != "" {
+			os.Setenv("NO_PROXY", v)
+			os.Setenv("no_proxy", v)
+		}
+	}
+
 	certs, err := x509.SystemCertPool()
 	if err != nil {
 		log.Error().Err(err).Msg("failed to find system CA certs")
@@ -105,4 +153,4 @@ func HTTPClientFromContext(c *cli.Command) *http.Client {
 	return &http.Client{
 		Transport: transport,
 	}
-}
+}

plugin.go

@@ -38,6 +38,10 @@ type Options struct {
 	Execute ExecuteFunc
 	// Context the plugin will use while executing.
 	Context context.Context
+	// EnableHTTPProxy allows plugins to opt-in to HTTP/HTTPS proxy support.
+	// When true, PLUGIN_HTTP_PROXY, PLUGIN_HTTPS_PROXY and PLUGIN_NO_PROXY
+	// are accepted as settings and applied to the HTTP client.
+	EnableHTTPProxy bool
 }
 
 // Plugin defines the plugin instance.
@@ -46,6 +50,8 @@ type Plugin struct {
 	execute ExecuteFunc
 	client  *http.Client
 	ctx     context.Context
+	// enableHTTPProxy controls whether HTTP proxy flags are registered and applied.
+	enableHTTPProxy bool
 	// Metadata of the current pipeline.
 	Metadata Metadata
 }
@@ -68,10 +74,16 @@ func New(opt Options) *Plugin {
 	}
 
 	plugin := &Plugin{
-		App:     app,
-		execute: opt.Execute,
-		ctx:     opt.Context,
+		App:             app,
+		execute:         opt.Execute,
+		ctx:             opt.Context,
+		enableHTTPProxy: opt.EnableHTTPProxy,
 	}
+
+	if opt.EnableHTTPProxy {
+		app.Flags = append(app.Flags, httpProxyFlags()...)
+	}
+
 	plugin.App.Action = plugin.action
 
 	if plugin.ctx == nil {
@@ -87,7 +99,7 @@ func (p *Plugin) action(ctx context.Context, c *cli.Command) error {
 	}
 
 	p.Metadata = MetadataFromContext(c)
-	p.client = HTTPClientFromContext(c)
+	p.client = HTTPClientFromContext(c, p.enableHTTPProxy)
 
 	if p.execute == nil {
 		panic("plugin execute function is not set")
@@ -107,4 +119,4 @@ func (p *Plugin) Run() {
 		log.Error().Err(err).Msg("execution failed")
 		os.Exit(1)
 	}
-}
+}