agent_start.go

package clicommand

import (
	"fmt"
	"os"
	"path/filepath"
	"runtime"
	"time"

	"github.com/buildkite/agent/agent"
	"github.com/buildkite/agent/cliconfig"
	"github.com/buildkite/agent/logger"
	"github.com/buildkite/shellwords"
	"github.com/urfave/cli"
)

var StartDescription = `Usage:

   buildkite-agent start [arguments...]

Description:

   When a job is ready to run it will call the "bootstrap-script"
   and pass it all the environment variables required for the job to run.
   This script is responsible for checking out the code, and running the
   actual build script defined in the pipeline.

   The agent will run any jobs within a PTY (pseudo terminal) if available.

Example:

   $ buildkite-agent start --token xxx`

// Adding config requires changes in a few different spots
// - The AgentStartConfig struct with a cli parameter
// - As a flag in the AgentStartCommand (with matching env)
// - Into an env to be passed to the bootstrap in agent/job_runner.go, createEnvironment()
// - Into clicommand/bootstrap.go to read it from the env into the bootstrap config

type AgentStartConfig struct {
	Config                    string   `cli:"config"`
	Token                     string   `cli:"token" validate:"required"`
	Name                      string   `cli:"name"`
	Priority                  string   `cli:"priority"`
	DisconnectAfterJob        bool     `cli:"disconnect-after-job"`
	DisconnectAfterJobTimeout int      `cli:"disconnect-after-job-timeout"`
	BootstrapScript           string   `cli:"bootstrap-script" normalize:"commandpath"`
	BuildPath                 string   `cli:"build-path" normalize:"filepath" validate:"required"`
	HooksPath                 string   `cli:"hooks-path" normalize:"filepath"`
	PluginsPath               string   `cli:"plugins-path" normalize:"filepath"`
	Shell                     string   `cli:"shell"`
	Tags                      []string `cli:"tags" normalize:"list"`
	TagsFromEC2               bool     `cli:"tags-from-ec2"`
	TagsFromEC2Tags           bool     `cli:"tags-from-ec2-tags"`
	TagsFromGCP               bool     `cli:"tags-from-gcp"`
	TagsFromHost              bool     `cli:"tags-from-host"`
	WaitForEC2TagsTimeout     string   `cli:"wait-for-ec2-tags-timeout"`
	GitCloneFlags             string   `cli:"git-clone-flags"`
	GitCleanFlags             string   `cli:"git-clean-flags"`
	NoGitSubmodules           bool     `cli:"no-git-submodules"`
	NoColor                   bool     `cli:"no-color"`
	NoSSHKeyscan              bool     `cli:"no-ssh-keyscan"`
	NoCommandEval             bool     `cli:"no-command-eval"`
	NoLocalHooks              bool     `cli:"no-local-hooks"`
	NoPlugins                 bool     `cli:"no-plugins"`
	NoPluginValidation        bool     `cli:"no-plugin-validation"`
	NoPTY                     bool     `cli:"no-pty"`
	TimestampLines            bool     `cli:"timestamp-lines"`
	Endpoint                  string   `cli:"endpoint" validate:"required"`
	Debug                     bool     `cli:"debug"`
	DebugHTTP                 bool     `cli:"debug-http"`
	Experiments               []string `cli:"experiment" normalize:"list"`

	/* Deprecated */
	NoSSHFingerprintVerification bool     `cli:"no-automatic-ssh-fingerprint-verification" deprecated-and-renamed-to:"NoSSHKeyscan"`
	MetaData                     []string `cli:"meta-data" deprecated-and-renamed-to:"Tags"`
	MetaDataEC2                  bool     `cli:"meta-data-ec2" deprecated-and-renamed-to:"TagsFromEC2"`
	MetaDataEC2Tags              bool     `cli:"meta-data-ec2-tags" deprecated-and-renamed-to:"TagsFromEC2Tags"`
	MetaDataGCP                  bool     `cli:"meta-data-gcp" deprecated-and-renamed-to:"TagsFromGCP"`
}

func DefaultShell() string {
	// https://github.com/golang/go/blob/master/src/go/build/syslist.go#L7
	switch runtime.GOOS {
	case "windows":
		return `C:\Windows\System32\CMD.exe /S /C`
	case "freebsd", "openbsd", "netbsd":
		return `/usr/local/bin/bash -e -c`
	default:
		return `/bin/bash -e -c`
	}
}

func DefaultConfigFilePaths() (paths []string) {
	// Toggle beetwen windows an *nix paths
	if runtime.GOOS == "windows" {
		paths = []string{
			"C:\\buildkite-agent\\buildkite-agent.cfg",
			"$USERPROFILE\\AppData\\Local\\BuildkiteAgent\\buildkite-agent.cfg",
		}
	} else {
		paths = []string{
			"$HOME/.buildkite-agent/buildkite-agent.cfg",
			"/usr/local/etc/buildkite-agent/buildkite-agent.cfg",
			"/etc/buildkite-agent/buildkite-agent.cfg",
		}
	}

	// Also check to see if there's a buildkite-agent.cfg in the folder
	// that the binary is running in.
	pathToBinary, err := filepath.Abs(filepath.Dir(os.Args[0]))
	if err == nil {
		pathToRelativeConfig := filepath.Join(pathToBinary, "buildkite-agent.cfg")
		paths = append([]string{pathToRelativeConfig}, paths...)
	}

	return
}

var AgentStartCommand = cli.Command{
	Name:        "start",
	Usage:       "Starts a Buildkite agent",
	Description: StartDescription,
	Flags: []cli.Flag{
		cli.StringFlag{
			Name:   "config",
			Value:  "",
			Usage:  "Path to a configuration file",
			EnvVar: "BUILDKITE_AGENT_CONFIG",
		},
		cli.StringFlag{
			Name:   "token",
			Value:  "",
			Usage:  "Your account agent token",
			EnvVar: "BUILDKITE_AGENT_TOKEN",
		},
		cli.StringFlag{
			Name:   "name",
			Value:  "",
			Usage:  "The name of the agent",
			EnvVar: "BUILDKITE_AGENT_NAME",
		},
		cli.StringFlag{
			Name:   "priority",
			Value:  "",
			Usage:  "The priority of the agent (higher priorities are assigned work first)",
			EnvVar: "BUILDKITE_AGENT_PRIORITY",
		},
		cli.BoolFlag{
			Name:   "disconnect-after-job",
			Usage:  "Disconnect the agent after running a job",
			EnvVar: "BUILDKITE_AGENT_DISCONNECT_AFTER_JOB",
		},
		cli.IntFlag{
			Name:   "disconnect-after-job-timeout",
			Value:  120,
			Usage:  "When --disconnect-after-job is specified, the number of seconds to wait for a job before shutting down",
			EnvVar: "BUILDKITE_AGENT_DISCONNECT_AFTER_JOB_TIMEOUT",
		},
		cli.StringFlag{
			Name:   "shell",
			Value:  DefaultShell(),
			Usage:  "The shell commamnd used to interpret build commands, e.g /bin/bash -e -c",
			EnvVar: "BUILDKITE_SHELL",
		},
		cli.StringSliceFlag{
			Name:   "tags",
			Value:  &cli.StringSlice{},
			Usage:  "A comma-separated list of tags for the agent (e.g. \"linux\" or \"mac,xcode=8\")",
			EnvVar: "BUILDKITE_AGENT_TAGS",
		},
		cli.BoolFlag{
			Name:   "tags-from-host",
			Usage:  "Include tags from the host (hostname, machine-id, os)",
			EnvVar: "BUILDKITE_AGENT_TAGS_FROM_HOST",
		},
		cli.BoolFlag{
			Name:   "tags-from-ec2",
			Usage:  "Include the host's EC2 meta-data as tags (instance-id, instance-type, and ami-id)",
			EnvVar: "BUILDKITE_AGENT_TAGS_FROM_EC2",
		},
		cli.BoolFlag{
			Name:   "tags-from-ec2-tags",
			Usage:  "Include the host's EC2 tags as tags",
			EnvVar: "BUILDKITE_AGENT_TAGS_FROM_EC2_TAGS",
		},
		cli.BoolFlag{
			Name:   "tags-from-gcp",
			Usage:  "Include the host's Google Cloud meta-data as tags (instance-id, machine-type, preemptible, project-id, region, and zone)",
			EnvVar: "BUILDKITE_AGENT_TAGS_FROM_GCP",
		},
		cli.DurationFlag{
			Name:   "wait-for-ec2-tags-timeout",
			Usage:  "The amount of time to wait for tags from EC2 before proceeding",
			EnvVar: "BUILDKITE_AGENT_WAIT_FOR_EC2_TAGS_TIMEOUT",
			Value:  time.Second * 10,
		},
		cli.StringFlag{
			Name:   "git-clone-flags",
			Value:  "-v",
			Usage:  "Flags to pass to the \"git clone\" command",
			EnvVar: "BUILDKITE_GIT_CLONE_FLAGS",
		},
		cli.StringFlag{
			Name:   "git-clean-flags",
			Value:  "-fxdq",
			Usage:  "Flags to pass to \"git clean\" command",
			EnvVar: "BUILDKITE_GIT_CLEAN_FLAGS",
		},
		cli.StringFlag{
			Name:   "bootstrap-script",
			Value:  "",
			Usage:  "The command that is executed for bootstrapping a job, defaults to the bootstrap sub-command of this binary",
			EnvVar: "BUILDKITE_BOOTSTRAP_SCRIPT_PATH",
		},
		cli.StringFlag{
			Name:   "build-path",
			Value:  "",
			Usage:  "Path to where the builds will run from",
			EnvVar: "BUILDKITE_BUILD_PATH",
		},
		cli.StringFlag{
			Name:   "hooks-path",
			Value:  "",
			Usage:  "Directory where the hook scripts are found",
			EnvVar: "BUILDKITE_HOOKS_PATH",
		},
		cli.StringFlag{
			Name:   "plugins-path",
			Value:  "",
			Usage:  "Directory where the plugins are saved to",
			EnvVar: "BUILDKITE_PLUGINS_PATH",
		},
		cli.BoolFlag{
			Name:   "timestamp-lines",
			Usage:  "Prepend timestamps on each line of output.",
			EnvVar: "BUILDKITE_TIMESTAMP_LINES",
		},
		cli.BoolFlag{
			Name:   "no-pty",
			Usage:  "Do not run jobs within a pseudo terminal",
			EnvVar: "BUILDKITE_NO_PTY",
		},
		cli.BoolFlag{
			Name:   "no-ssh-keyscan",
			Usage:  "Don't automatically run ssh-keyscan before checkout",
			EnvVar: "BUILDKITE_NO_SSH_KEYSCAN",
		},
		cli.BoolFlag{
			Name:   "no-command-eval",
			Usage:  "Don't allow this agent to run arbitrary console commands, including plugins",
			EnvVar: "BUILDKITE_NO_COMMAND_EVAL",
		},
		cli.BoolFlag{
			Name:   "no-plugins",
			Usage:  "Don't allow this agent to load plugins",
			EnvVar: "BUILDKITE_NO_PLUGINS",
		},
		cli.BoolTFlag{
			Name:   "no-plugin-validation",
			Usage:  "Don't validate plugin configuration and requirements",
			EnvVar: "BUILDKITE_NO_PLUGIN_VALIDATION",
		},
		cli.BoolFlag{
			Name:   "no-local-hooks",
			Usage:  "Don't allow local hooks to be run from checked out repositories",
			EnvVar: "BUILDKITE_NO_LOCAL_HOOKS",
		},
		cli.BoolFlag{
			Name:   "no-git-submodules",
			Usage:  "Don't automatically checkout git submodules",
			EnvVar: "BUILDKITE_NO_GIT_SUBMODULES,BUILDKITE_DISABLE_GIT_SUBMODULES",
		},
		ExperimentsFlag,
		EndpointFlag,
		NoColorFlag,
		DebugFlag,
		DebugHTTPFlag,
		/* Deprecated flags which will be removed in v4 */
		cli.StringSliceFlag{
			Name:   "meta-data",
			Value:  &cli.StringSlice{},
			Hidden: true,
			EnvVar: "BUILDKITE_AGENT_META_DATA",
		},
		cli.BoolFlag{
			Name:   "meta-data-ec2",
			Hidden: true,
			EnvVar: "BUILDKITE_AGENT_META_DATA_EC2",
		},
		cli.BoolFlag{
			Name:   "meta-data-ec2-tags",
			Hidden: true,
			EnvVar: "BUILDKITE_AGENT_TAGS_FROM_EC2_TAGS",
		},
		cli.BoolFlag{
			Name:   "meta-data-gcp",
			Hidden: true,
			EnvVar: "BUILDKITE_AGENT_META_DATA_GCP",
		},
		cli.BoolFlag{
			Name:   "no-automatic-ssh-fingerprint-verification",
			Hidden: true,
			EnvVar: "BUILDKITE_NO_AUTOMATIC_SSH_FINGERPRINT_VERIFICATION",
		},
	},
	Action: func(c *cli.Context) {
		// The configuration will be loaded into this struct
		cfg := AgentStartConfig{}

		// Setup the config loader. You'll see that we also path paths to
		// potential config files. The loader will use the first one it finds.
		loader := cliconfig.Loader{
			CLI:                    c,
			Config:                 &cfg,
			DefaultConfigFilePaths: DefaultConfigFilePaths(),
		}

		// Load the configuration
		if err := loader.Load(); err != nil {
			logger.Fatal("%s", err)
		}

		// Setup the any global configuration options
		HandleGlobalFlags(cfg)

		// Force some settings if on Windows (these aren't supported yet)
		if runtime.GOOS == "windows" {
			cfg.NoPTY = true
		}

		// Set a useful default for the bootstrap script
		if cfg.BootstrapScript == "" {
			cfg.BootstrapScript = fmt.Sprintf("%s bootstrap", shellwords.Quote(os.Args[0]))
		}

		// Show a warning if plugins are enabled by no-command-eval or no-local-hooks is set
		if c.IsSet("no-plugins") && cfg.NoPlugins == false {
			msg := `Plugins have been specifically enabled, despite %s being enabled. ` +
				`Plugins can execute arbitrary hooks and commands, make sure you are ` +
				`whitelisting your plugins in ` +
				`your environment hook.`

			switch {
			case cfg.NoCommandEval:
				logger.Warn(msg, `no-command-eval`)
			case cfg.NoLocalHooks:
				logger.Warn(msg, `no-local-hooks`)
			}
		}

		// Turning off command eval or local hooks will also turn off plugins unless
		// `--no-plugins=false` is provided specifically
		if (cfg.NoCommandEval || cfg.NoLocalHooks) && !c.IsSet("no-plugins") {
			cfg.NoPlugins = true
		}

		// Guess the shell if none is provided
		if cfg.Shell == "" {
			cfg.Shell = DefaultShell()
		}

		// Make sure the DisconnectAfterJobTimeout value is correct
		if cfg.DisconnectAfterJob && cfg.DisconnectAfterJobTimeout < 120 {
			logger.Fatal("The timeout for `disconnect-after-job` must be at least 120 seconds")
		}

		var ec2TagTimeout time.Duration
		if t := cfg.WaitForEC2TagsTimeout; t != "" {
			var err error
			ec2TagTimeout, err = time.ParseDuration(t)
			if err != nil {
				logger.Fatal("Failed to parse ec2 tag timeout: %v", err)
			}
		}

		// Setup the agent
		pool := agent.AgentPool{
			Token:                 cfg.Token,
			Name:                  cfg.Name,
			Priority:              cfg.Priority,
			Tags:                  cfg.Tags,
			TagsFromEC2:           cfg.TagsFromEC2,
			TagsFromEC2Tags:       cfg.TagsFromEC2Tags,
			TagsFromGCP:           cfg.TagsFromGCP,
			TagsFromHost:          cfg.TagsFromHost,
			WaitForEC2TagsTimeout: ec2TagTimeout,
			Endpoint:              cfg.Endpoint,
			AgentConfiguration: &agent.AgentConfiguration{
				BootstrapScript:           cfg.BootstrapScript,
				BuildPath:                 cfg.BuildPath,
				HooksPath:                 cfg.HooksPath,
				PluginsPath:               cfg.PluginsPath,
				GitCloneFlags:             cfg.GitCloneFlags,
				GitCleanFlags:             cfg.GitCleanFlags,
				GitSubmodules:             !cfg.NoGitSubmodules,
				SSHKeyscan:                !cfg.NoSSHKeyscan,
				CommandEval:               !cfg.NoCommandEval,
				PluginsEnabled:            !cfg.NoPlugins,
				PluginValidation:          !cfg.NoPluginValidation,
				LocalHooksEnabled:         !cfg.NoLocalHooks,
				RunInPty:                  !cfg.NoPTY,
				TimestampLines:            cfg.TimestampLines,
				DisconnectAfterJob:        cfg.DisconnectAfterJob,
				DisconnectAfterJobTimeout: cfg.DisconnectAfterJobTimeout,
				Shell: cfg.Shell,
			},
		}

		// Store the loaded config file path on the pool and agent config so we can
		// show it when the agent starts and set an env
		if loader.File != nil {
			pool.ConfigFilePath = loader.File.Path
			pool.AgentConfiguration.ConfigPath = loader.File.Path
		}

		// Start the agent pool
		if err := pool.Start(); err != nil {
			logger.Fatal("%s", err)
		}
	},
}