bs

package module
v0.1.4 Latest Latest
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 Go to latest Published: Sep 6, 2021 License: MIT Imports: 13 Imported by: 0

README

bs

Overview

bs is a package to streamline building bash-like scripts.

The original intended use was inside a Magefile, but there's nothing stopping you from using this in a regular Go app.

Features include:

  • Echo/Warn/Verbose for outputting lines
    • Verbose defaults to only printing if MAGEFILE_VERBOSE is set to true (mirroring how Mage's mg.Verbose() works), but the specific env var that is checked can be changed by calling SetVerboseEnvVarName.
  • ANSI color support (which respects NO_COLOR env var)
  • Protect secrets from being visible on-screen or in logs via PushEchoFilter/PopEchoFilter
  • Read files to strings (or []byte)
  • Write or Append strings (or []byte) to files
  • Run commands via bash-like parsing of arguments, with support for redirecting stdin/out/err
  • Command variants that can return stdout as string, exit code as int, or Go error
  • Common File/Folder helpers, like Exists, IsFile, IsDir, Getwd, Chdir, Mkdir, MkdirAll, Remove, RemoveAll, etc
  • Global error handler that allows most bs commands to not require exlicit error handling
    • This mimics bash's set -e, where any error results in a panic
    • The default "panic" behavior is overridable via a call to SetErrorHandler.

Example

I've got an example magefile below, but first, here's what the output looks like:

example terminal output

And then here's that same output, but with mage's "verbose" flag set:

example terminal output with verbose output

And here's the corresponding magefile.go:

// +build mage

package main

import (
  "fmt"
  "regexp"
  "strings"

  "github.com/danbrakeley/bs"
  "github.com/magefile/mage/mg"
)

// BUILD COMMANDS

// Builds ardentd into the "local" folder.
func Build() {
  target := bs.ExeName("ardentd")

  bs.Echo("Running tests...")
  bs.Cmd("go test ./...").Run()

  bs.Echof("Building %s...", target)
  bs.MkdirAll("local/")
  bs.Cmdf("go build -o local/%s ./cmd/ardentd", target).Run()
}

// Removes all artifacts from previous builds.
// At the moment, this is accomplished by deleting the "local" folder.
func Clean() {
  bs.Echo("Deleting local...")
  bs.RemoveAll("local")
}

// Runs ardentd.
func Run() {
  mg.Deps(Build)

  target := bs.ExeName("ardentd")
  password := pgGetPass()
  bs.PushEchoFilter(password)
  defer bs.PopEchoFilter()
  pgURL := fmt.Sprintf("postgres://%s:%s@localhost:%s/%s?sslmode=disable", PG_USERNAME, password, PG_PORT, PG_DBNAME)

  bs.Chdir("local")
  bs.Echo("Running...")
  bs.Cmdf("%s", target).Env(
    "ARDENT_HOST=127.0.0.1:8080",
    "ARDENT_PGURL="+pgURL,
    "ARDENT_VERBOSE=true",
  ).Run()
}

// POSTGRES COMMANDS

// Passes command to Postgres: help, start, stop, destroy
func PG(cmd string) {
  cmd = strings.ToLower(cmd)
  switch cmd {
  case "start":
    pgStart()
  case "stop":
    pgStop()
  case "destroy":
    pgDestroy()
  case "psql":
    pgPsql()
  default:
    if cmd != "help" {
      bs.Warnf(`Unrecognized command "%s"`, cmd)
    }
    bs.Echo("pg start   - Starts the postgres docker container. If the container didn't previously exist, it is created.")
    bs.Echo("pg stop    - Stops the postgres docker container.")
    bs.Echo("pg destroy - Destroys the postgres docker container (including data).")
    bs.Echo("pg psql    - Starts psql interactive shell against running postgres db.")
  }
}

const (
  PG_DOCKER_IMAGE   = "postgres:13-alpine"
  PG_CONTAINER_NAME = "psql-ardent"
  PG_DBNAME         = "ardent"
  PG_USERNAME       = "super"
  PG_PASS_FILE      = "pg.pass.local"
  PG_PORT           = "5444"
)

func pgStart() {
  existingContainer := bs.Cmd(`docker ps --filter "name=` + PG_CONTAINER_NAME + `" -q -a`).RunStr()
  if len(existingContainer) > 0 {
    bs.Cmd("docker start " + PG_CONTAINER_NAME).OutErr(nil).Run()
  } else {
    if !bs.Exists(PG_PASS_FILE) {
      bs.Warnf(`Please create a file named "%s" that contains the database password.`, PG_PASS_FILE)
      return
    }
    pgpass := pgGetPass()
    bs.PushEchoFilter(pgpass)
    defer bs.PopEchoFilter()
    bs.Cmd(
      "docker run --name " + PG_CONTAINER_NAME +
        " -e POSTGRES_PASSWORD=" + pgpass +
        " -e POSTGRES_USER=" + PG_USERNAME +
        " -e POSTGRES_DB=" + PG_DBNAME +
        " --publish " + PG_PORT + ":5432" +
        " --detach " + PG_DOCKER_IMAGE,
    ).Run()
  }

  bs.Cmd(`docker ps --filter "name=` + PG_CONTAINER_NAME + `" -a`).Run()
}

func pgStop() {
  bs.Cmd("docker stop " + PG_CONTAINER_NAME).OutErr(nil).Run()
  bs.Cmd(`docker ps --filter "name=` + PG_CONTAINER_NAME + `" -a`).Run()
}

func pgDestroy() {
  deletePhrase := bs.Ask(`This will delete all data. To continue, type "i've been warned" (without quotes): `)
  if deletePhrase == "i've been warned" {
    bs.Cmd("docker stop " + PG_CONTAINER_NAME).OutErr(nil).Run()
    bs.Cmd("docker rm " + PG_CONTAINER_NAME).OutErr(nil).Run()
  } else {
    bs.Warnf(`You typed "%s", which was not what was asked for, so nothing was deleted.`, deletePhrase)
  }
}

func pgPsql() {
  pgpass := pgGetPass()
  bs.PushEchoFilter(pgpass)
  defer bs.PopEchoFilter()
  bs.Cmdf(
    `docker exec -it --env PGPASSWORD=%s %s psql -h localhost -d %s -U %s`,
    pgpass, PG_CONTAINER_NAME, PG_DBNAME, PG_USERNAME,
  ).Run()
}

// GOOSE COMMANDS

// Calls "goose {cmd}", where {cmd} is one of: status, up, up-by-one, down, redo, reset, or version
func Goose(cmd string) {
  password := pgGetPass()
  bs.PushEchoFilter(password)
  defer bs.PopEchoFilter()
  bs.Cmdf("goose -dir sql %s", cmd).Env("GOOSE_DRIVER=postgres", "GOOSE_DBSTRING="+pgDSN(password)).Run()
}

// helpers

var regexpPassword = regexp.MustCompile(`^[a-zA-Z0-9_]+$`)

func pgGetPass() string {
  str := strings.TrimSpace(strings.Split(bs.Read(PG_PASS_FILE), "\n")[0])
  if !regexpPassword.MatchString(str) {
    panic(fmt.Errorf(`Password is only allowed alphanumerics and underscores. Please change "%s" by hand to fix.`, PG_PASS_FILE))
  }
  return str
}

func pgDSN(password string) string {
  return fmt.Sprintf(
    "host=localhost port=%s user=%s password=%s dbname=%s sslmode=disable",
    PG_PORT, PG_USERNAME, password, PG_DBNAME,
  )
}

Documentation

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func Append 

func Append(path string, contents string)

func AppendBytes 

func AppendBytes(path string, b []byte)

func AppendBytesErr 

func AppendBytesErr(path string, b []byte) error

func AppendErr 

func AppendErr(path string, contents string) error

func Appendf 

func Appendf(path string, format string, args ...interface{})

func Ask 

func Ask(msg string) string

func Askf 

func Askf(format string, args ...interface{}) string

func Chdir 

func Chdir(dir string)

func Echo 

func Echo(str string)

func Echof 

func Echof(format string, args ...interface{})

func ExeName 

func ExeName(path string) string

ExeName adds ".exe" to passed string if GOOS is windows

func Exists 

func Exists(path string) bool

func Getwd 

func Getwd() string

func IsDir 

func IsDir(path string) bool

func IsFile 

func IsFile(path string) bool

func IsVerbose added in v0.1.3 

func IsVerbose() bool

func MkdirAll 

func MkdirAll(dir string)

func PopEchoFilter 

func PopEchoFilter()

func PushEchoFilter 

func PushEchoFilter(str string)

func Read 

func Read(path string) string

func ReadErr 

func ReadErr(path string) (string, error)

func ReadFile 

func ReadFile(path string) []byte

func Remove 

func Remove(dir string)

TODO: if file doesn't exist, don't err

func RemoveAll 

func RemoveAll(dir string)

func ScanLine 

func ScanLine() string

func ScanLineErr 

func ScanLineErr() (string, error)

func SetColorsEnabled added in v0.1.4 

func SetColorsEnabled(enabled bool)

func SetErrorHandler 

func SetErrorHandler(fnErr func(err error))

SetErrorHandler sets the behavior when an error is encountered while running most commands. The default behavior is to panic.

func SetStderr 

func SetStderr(w io.Writer)

SetStderr overrides stderr for Run*/Bash* (defaults to os.Stderr)

func SetStdin 

func SetStdin(r io.Reader)

SetStdin overrides stdin for Run*/Bash*/Read* (defaults to os.Stdin)

func SetStdout 

func SetStdout(w io.Writer)

SetStdout overrides stdout for Run*/Bash* (defaults to os.Stdout)

func SetVerbose added in v0.1.3 

func SetVerbose(b bool)

func SetVerboseEnvVarName added in v0.1.3 

func SetVerboseEnvVarName(s string)

SetVerboseEnvVarName allows changing the name of the environment variable that is used to decide if we are in Verbose mode. This function creates the new env var immediately, setting its value to true or false based on the value of the old env var name.

func Stat 

func Stat(path string) fs.FileInfo

func Verbose 

func Verbose(str string)

func Verbosef 

func Verbosef(format string, args ...interface{})

func Warn 

func Warn(str string)

func Warnf 

func Warnf(format string, args ...interface{})

func Write 

func Write(path string, contents string)

func WriteBytes 

func WriteBytes(path string, b []byte)

func WriteBytesErr 

func WriteBytesErr(path string, b []byte) error

func WriteErr 

func WriteErr(path string, contents string) error

func Writef 

func Writef(path string, format string, args ...interface{})

Types

type Command 

type Command struct {
	// contains filtered or unexported fields
}

func Cmd 

func Cmd(command string) *Command

func Cmdf 

func Cmdf(format string, args ...interface{}) *Command

func (*Command) Bash 

func (c *Command) Bash()

func (*Command) BashErr 

func (c *Command) BashErr() error

func (*Command) BashExitStatus 

func (c *Command) BashExitStatus() int

func (*Command) BashStr 

func (c *Command) BashStr() string

func (*Command) Env 

func (c *Command) Env(vars ...string) *Command

Env adds environment variables in the form "KEY=VALUE", to be set on exec.Cmd.Env. Note: these env vars are not seen by ExpandEnv.

func (*Command) Err 

func (c *Command) Err(out io.Writer) *Command

func (*Command) ExitStatus 

func (c *Command) ExitStatus(n *int) *Command

func (*Command) ExpandEnv 

func (c *Command) ExpandEnv() *Command

ExpandEnv calls os.ExpandEnv on the command string before it is parsed and passed to exec.Cmd.

func (*Command) In 

func (c *Command) In(in io.Reader) *Command

func (*Command) Out 

func (c *Command) Out(out io.Writer) *Command

func (*Command) OutErr 

func (c *Command) OutErr(out io.Writer) *Command

func (*Command) Run 

func (c *Command) Run()

func (*Command) RunErr 

func (c *Command) RunErr() error

func (*Command) RunExitStatus 

func (c *Command) RunExitStatus() int

func (*Command) RunStr 

func (c *Command) RunStr() string

Source Files

View all Source files

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