Add Forge metadata (#20)

Adds support for loading Forge metadata from env variables

Reviewed-on: https://codeberg.org/woodpecker-plugins/go-plugin/pulls/20
Reviewed-by: qwerty287 <qwerty287@noreply.codeberg.org>
Co-authored-by: Lauris BH <lauris@nix.lv>
Co-committed-by: Lauris BH <lauris@nix.lv>

forge.go

@@ -0,0 +1,59 @@
+// Copyright 2023 Woodpecker Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package plugin
+
+import (
+	"github.com/urfave/cli/v2"
+)
+
+const (
+	ForgeTypeGitea     = "gitea"
+	ForgeTypeGitHub    = "github"
+	ForgeTypeGitLab    = "gitlab"
+	ForgeTypeBitbucket = "bitbucket"
+)
+
+// Forge defines metadata for integration with a forge.
+type Forge struct {
+	Type string `json:"type,omitempty"`
+	Link string `json:"link,omitempty"`
+}
+
+func forgeFlags() []cli.Flag {
+	return []cli.Flag{
+		&cli.StringFlag{
+			Name:  "forge.type",
+			Usage: "forge type (gitea, github, gitlab, bitbucker)",
+			EnvVars: []string{
+				"CI_FORGE_TYPE",
+			},
+		},
+		&cli.StringFlag{
+			Name:  "forge.link",
+			Usage: "forge link",
+			EnvVars: []string{
+				"CI_FORGE_URL",
+				"CI_FORGE_LINK",
+			},
+		},
+	}
+}
+
+func forgeFromContext(ctx *cli.Context) Forge {
+	return Forge{
+		Type: ctx.String("forge.type"),
+		Link: ctx.String("forge.link"),
+	}
+}