build: improve debian packaging

This commit tweaks the debian packaging tool:

* All build environment metadata can now be overriden on the command
  line. This allows testing the CI build behaviour locally.
* -unstable packages now actually contain the binaries (oops)
* packages use Go 1.7 to build
* archiving is skipped for PR builds

internal/build/env.go

@@ -0,0 +1,114 @@
+// Copyright 2016 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package build
+
+import (
+	"flag"
+	"fmt"
+	"os"
+)
+
+var (
+	// These flags override values in build env.
+	GitCommitFlag   = flag.String("git-commit", "", `Overrides git commit hash embedded into executables`)
+	GitBranchFlag   = flag.String("git-branch", "", `Overrides git branch being built`)
+	GitTagFlag      = flag.String("git-tag", "", `Overrides git tag being built`)
+	BuildnumFlag    = flag.String("buildnum", "", `Overrides CI build number`)
+	PullRequestFlag = flag.Bool("pull-request", false, `Overrides pull request status of the build`)
+)
+
+// Environment contains metadata provided by the build environment.
+type Environment struct {
+	Name                string // name of the environment
+	Repo                string // name of GitHub repo
+	Commit, Branch, Tag string // Git info
+	Buildnum            string
+	IsPullRequest       bool
+}
+
+func (env Environment) String() string {
+	return fmt.Sprintf("%s env (commit:%s branch:%s tag:%s buildnum:%s pr:%t)",
+		env.Name, env.Commit, env.Branch, env.Tag, env.Buildnum, env.IsPullRequest)
+}
+
+// Env returns metadata about the current CI environment, falling back to LocalEnv
+// if not running on CI.
+func Env() Environment {
+	switch {
+	case os.Getenv("CI") == "true" && os.Getenv("TRAVIS") == "true":
+		return Environment{
+			Name:          "travis",
+			Repo:          os.Getenv("TRAVIS_REPO_SLUG"),
+			Commit:        os.Getenv("TRAVIS_COMMIT"),
+			Branch:        os.Getenv("TRAVIS_BRANCH"),
+			Tag:           os.Getenv("TRAVIS_TAG"),
+			Buildnum:      os.Getenv("TRAVIS_BUILD_NUMBER"),
+			IsPullRequest: os.Getenv("TRAVIS_PULL_REQUEST") != "false",
+		}
+	case os.Getenv("CI") == "True" && os.Getenv("APPVEYOR") == "True":
+		return Environment{
+			Name:          "appveyor",
+			Repo:          os.Getenv("APPVEYOR_REPO_NAME"),
+			Commit:        os.Getenv("APPVEYOR_REPO_COMMIT"),
+			Branch:        os.Getenv("APPVEYOR_REPO_BRANCH"),
+			Tag:           os.Getenv("APPVEYOR_REPO_TAG"),
+			Buildnum:      os.Getenv("APPVEYOR_BUILD_NUMBER"),
+			IsPullRequest: os.Getenv("APPVEYOR_PULL_REQUEST_NUMBER") != "",
+		}
+	default:
+		return LocalEnv()
+	}
+}
+
+// LocalEnv returns build environment metadata gathered from git.
+func LocalEnv() Environment {
+	env := applyEnvFlags(Environment{Name: "local", Repo: "ethereum/go-ethereum"})
+	if _, err := os.Stat(".git"); err != nil {
+		return env
+	}
+	if env.Commit == "" {
+		env.Commit = RunGit("rev-parse", "HEAD")
+	}
+	if env.Branch == "" {
+		env.Branch = RunGit("symbolic-ref", "-q", "--short", "HEAD")
+	}
+	// Note that we don't get the current git tag. It would slow down
+	// builds and isn't used by anything.
+	return env
+}
+
+func applyEnvFlags(env Environment) Environment {
+	if !flag.Parsed() {
+		panic("you need to call flag.Parse before Env or LocalEnv")
+	}
+	if *GitCommitFlag != "" {
+		env.Commit = *GitCommitFlag
+	}
+	if *GitBranchFlag != "" {
+		env.Branch = *GitBranchFlag
+	}
+	if *GitTagFlag != "" {
+		env.Tag = *GitTagFlag
+	}
+	if *BuildnumFlag != "" {
+		env.Buildnum = *BuildnumFlag
+	}
+	if *PullRequestFlag {
+		env.IsPullRequest = true
+	}
+	return env
+}