initial commit for a mercurial plugin. wip

.drone.yml

@@ -0,0 +1,31 @@
+build:
+  image: golang:1.5
+  environment:
+    - GO15VENDOREXPERIMENT=1
+    - GOOS=linux
+    - GOARCH=amd64
+    - CGO_ENABLED=0
+  commands:
+    - go get
+    - go build
+    - go test
+
+publish:
+  docker:
+    username: drone
+    password: $$DOCKER_PASS
+    email: $$DOCKER_EMAIL
+    repo: plugins/drone-hg
+    when:
+      branch: master
+
+plugin:
+  name: Mercurial
+  desc: Clones a mercurial repository.
+  type: clone
+  image: plugins/drone-hg
+  labels:
+    - scm
+    - vcs
+    - hg
+

.gitignore

@@ -22,3 +22,5 @@ _testmain.go
 *.exe
 *.test
 *.prof
+
+drone-hg

DOCS.md

@@ -0,0 +1,13 @@
+Use the Mercurial plugin to clone a mercurial repository. Note that Drone uses this plugin
+by default for all Bitbucket mercurial repositories, without any configuration required. You can override
+the default configuration with the following parameters:
+
+* `path` relative path inside /drone/src where the repository is cloned
+
+The following is a sample Git clone configuration in your .drone.yml file:
+
+```yaml
+clone:
+  image: hg
+  path: bitbucket.org/foo/bar
+```

Dockerfile

@@ -0,0 +1,9 @@
+# Docker image for Drone's git-clone plugin
+#
+#     CGO_ENABLED=0 go build -a -tags netgo
+#     docker build --rm=true -t plugins/drone-hg .
+
+FROM alpine:3.2
+RUN apk add -U ca-certificates git openssh curl perl && rm -rf /var/cache/apk/*
+ADD drone-hg /bin/
+ENTRYPOINT ["/bin/drone-hg"]

main.go

@@ -0,0 +1,134 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"os/user"
+	"path/filepath"
+	"strings"
+
+	"github.com/drone/drone-plugin-go/plugin"
+)
+
+var hgrcFile = `
+[auth]
+bb.prefix = https://bitbucket.org
+bb.username = %s
+bb.password = %s
+`
+
+// Params stores the git clone parameters used to
+// configure and customzie the git clone behavior.
+type Params struct {
+}
+
+func main() {
+	v := new(Params)
+	r := new(plugin.Repo)
+	b := new(plugin.Build)
+	w := new(plugin.Workspace)
+	plugin.Param("repo", r)
+	plugin.Param("build", b)
+	plugin.Param("workspace", w)
+	plugin.Param("vargs", &v)
+	plugin.MustParse()
+
+	err := run(r, b, w, v)
+	if err != nil {
+		os.Exit(1)
+	}
+}
+
+// run clones the repository and build revision
+// into the build workspace.
+func run(r *plugin.Repo, b *plugin.Build, w *plugin.Workspace, v *Params) error {
+
+	err := os.MkdirAll(w.Path, 0777)
+	if err != nil {
+		fmt.Printf("Error creating directory %s. %s\n", w.Path, err)
+		return err
+	}
+
+	// generate the .hgrc file
+	if err := writeHgrc(w); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		return err
+	}
+
+	var cmds []*exec.Cmd
+	cmds = append(cmds, clone(b))
+	cmds = append(cmds, update(b))
+
+	for _, cmd := range cmds {
+		cmd.Dir = w.Path
+		cmd.Stdout = os.Stdout
+		cmd.Stderr = os.Stderr
+		trace(cmd)
+		err := cmd.Run()
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func clone(b *plugin.Build) *exec.Cmd {
+	return exec.Command(
+		"hg",
+		"clone",
+		"--branch",
+		b.Branch,
+	)
+}
+
+func update(b *plugin.Build) *exec.Cmd {
+	return exec.Command(
+		"hg",
+		"update",
+		b.Commit,
+	)
+}
+
+// Trace writes each command to standard error (preceded by a ‘$ ’) before it
+// is executed. Used for debugging your build.
+func trace(cmd *exec.Cmd) {
+	fmt.Println("$", strings.Join(cmd.Args, " "))
+}
+
+// Writes the hgrc file.
+func writeHgrc(in *plugin.Workspace) error {
+	if in.Netrc == nil || len(in.Netrc.Machine) == 0 {
+		return nil
+	}
+	out := fmt.Sprintf(
+		hgrcFile,
+		in.Netrc.Machine, // TODO this may require adding http(s) prefix
+		in.Netrc.Login,
+		in.Netrc.Password,
+	)
+	home := "/root/.hg"
+	u, err := user.Current()
+	if err == nil {
+		home = u.HomeDir
+	}
+	path := filepath.Join(home, "hgrc")
+	return ioutil.WriteFile(path, []byte(out), 0600)
+}
+
+func isDirEmpty(name string) bool {
+	f, err := os.Open(name)
+	if err != nil {
+		return true
+	}
+	defer f.Close()
+
+	_, err = f.Readdir(1)
+	if err == io.EOF {
+		return true
+	}
+	return false
+}