update dependencies to fix dependabot warnings.

This gets rid of the warning about mismatched test sizes.

LICENSE

@@ -1,4 +1,4 @@
-Copyright (c) 2015 Kyle Isom <kyle@tyrfingr.is>
+Copyright (c) 2015-2023 Kyle Isom <kyle@tyrfingr.is>
 
 Permission to use, copy, modify, and distribute this software for any
 purpose with or without fee is hereby granted, provided that the above 

README.md

@@ -1,10 +1,12 @@
 GOUTILS
 
-### Note: this repo is archived and not being maintained here anymore.
-
 This is a collection of small utility code I've written in Go; the `cmd/`
 directory has a number of command-line utilities. Rather than keep all
-of these in superfluous repositories of their own, I'm putting them here.
+of these in superfluous repositories of their own, or rewriting them
+for each project, I'm putting them here.
+
+The project can be built with the standard Go tooling, or it can be built
+with Bazel.
 
 Contents:
 
@@ -25,33 +27,46 @@ Contents:
         cruntar/    Untar an archive with hard links, copying instead of
                     linking.
         csrpubdump/ Dump the public key from an X.509 certificate request.
+	diskimg/    Write a disk image to a device.
+	eig/	    EEPROM image generator.
         fragment/   Print a fragment of a file.
         jlp/        JSON linter/prettifier.
         kgz/        Custom gzip compressor / decompressor that handles 99%
                     of my use cases.
+	parts/	    Simple parts database management for my collection of
+		    electronic components.
         pem2bin/    Dump the binary body of a PEM-encoded block.
         pembody/    Print the body of a PEM certificate.
         pemit/      Dump data to a PEM file.
-        showimp/    List the external (e.g. non-stdlib and outside the
-                    current working directory) imports for a Go file.
         readchain/  Print the common name for the certificates
                     in a bundle.
         renfnv/     Rename a file to base32-encoded 64-bit FNV-1a hash.
         rhash/      Compute the digest of remote files.
-        showimp     Display the external imports in a package.
+        showimp/    List the external (e.g. non-stdlib and outside the
+                    current working directory) imports for a Go file.
         ski         Display the SKI for PEM-encoded TLS material.
+	sprox/	    Simple TCP proxy.
         stealchain/ Dump the verified chain from a TLS 
-                    connection.
+                    connection to a server.
+	stealchain- Dump the verified chain from a TLS 
+	  server/   connection from a client.
         subjhash/   Print or match subject info from a certificate.
         tlskeypair/ Check whether a TLS certificate and key file match.
         utc/        Convert times to UTC.
         yamll/      A small YAML linter.
+    config/	    A simple global configuration system where configuration
+    		    data is pulled from a file or an environment variable
+		    transparently.
+    dbg/	    A debug printer.
     die/            Death of a program.
     fileutil/       Common file functions.
     lib/            Commonly-useful functions for writing Go programs.
     logging/        A logging library.
     mwc/            MultiwriteCloser implementation.
+    rand/	    Utilities for working with math/rand.
     sbuf/           A byte buffer that can be wiped.
+    seekbuf/	    A read-seekable byte buffer.
+    syslog/	    Syslog-type logging.
     tee/            Emulate tee(1)'s functionality in io.Writers.
     testio/         Various I/O utilities useful during testing.
     testutil/       Various utility functions useful during testing.
@@ -60,4 +75,4 @@ Contents:
 Each program should have a small README in the directory with more
 information.
 
-All code here is licensed under the MIT license.
+All code here is licensed under the ISC license.

WORKSPACE

@@ -1,5 +1,7 @@
 load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 
+
+### Go tooling, including Gazelle to generate and maintain BUILD files.
 http_archive(
     name = "io_bazel_rules_go",
     sha256 = "6b65cb7917b4d1709f9410ffe00ecf3e160edf674b78c54a894471320862184f",
@@ -20,20 +22,22 @@ http_archive(
 
 load("@io_bazel_rules_go//go:deps.bzl", "go_register_toolchains", "go_rules_dependencies")
 load("@bazel_gazelle//:deps.bzl", "gazelle_dependencies")
-
-############################################################
-# Define your own dependencies here using go_repository.
-# Else, dependencies declared by rules_go/gazelle will be used.
-# The first declaration of an external repository "wins".
-############################################################
-
 load("//:deps.bzl", "go_dependencies")
 
 # gazelle:repository_macro deps.bzl%go_dependencies
 go_dependencies()
-
 go_rules_dependencies()
-
 go_register_toolchains(version = "1.20.4")
-
 gazelle_dependencies()
+
+### Packaging rules
+http_archive(
+	name = "rules_pkg",
+	urls = [
+		"https://mirror.bazel.build/github.com/bazelbuild/rules_pkg/releases/download/0.9.1/rules_pkg-0.9.1.tar.gz",
+		"https://github.com/bazelbuild/rules_pkg/releases/download/0.9.1/rules_pkg-0.9.1.tar.gz",
+	],
+	sha256 = "8f9ee2dc10c1ae514ee599a8b42ed99fa262b757058f65ad3c384289ff70c4b8",
+)
+load("@rules_pkg//:deps.bzl", "rules_pkg_dependencies")
+rules_pkg_dependencies()

cmd/diskimg/BUILD.bazel

@@ -0,0 +1,19 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_binary", "go_library")
+
+go_library(
+    name = "diskimg_lib",
+    srcs = ["main.go"],
+    importpath = "git.wntrmute.dev/kyle/goutils/cmd/diskimg",
+    visibility = ["//visibility:private"],
+    deps = [
+        "//ahash",
+        "//dbg",
+        "//die",
+    ],
+)
+
+go_binary(
+    name = "diskimg",
+    embed = [":diskimg_lib"],
+    visibility = ["//visibility:public"],
+)

cmd/diskimg/README

@@ -0,0 +1,34 @@
+diskimg: write disk images
+
+Usage:
+	diskimg [-a algo] [-v] image device
+
+Flags:
+	-a algo		Select the hashing algorithm to use. The default
+			is 'sha256'. Specifying an algorithm of 'list'
+			will print the supported algorithms to standard
+			output and exit with error code 2.
+	-v		Enable verbose (debug) output.
+
+Examples:
+	
+	Copying images/server.img to /dev/sda:
+
+	$ sudo diskimg images/server.img /dev/sda
+
+	Write a bladerunner node image to /dev/sda:
+
+	$ sudo diskimg -v ~/code/bladerunner/packer/build/cm4-cnode-ubuntu-22.04.2.img /dev/sda
+	opening image /home/kyle/code/bladerunner/packer/build/cm4-cnode-ubuntu-22.04.2.img for read
+	/home/kyle/code/bladerunner/packer/build/cm4-cnode-ubuntu-22.04.2.img  416d4c8f890904167419e3d488d097e9c847273376b650546fdb1f6f9809c184
+	opening device /dev/sda for rw
+	writing /home/kyle/code/bladerunner/packer/build/cm4-cnode-ubuntu-22.04.2.img -> /dev/sda
+	wrote 4151312384 bytes to /dev/sda
+	syncing /dev/sda
+	verifying the image was written successfully
+	OK
+
+Motivation:
+
+	I wanted to write something like balena's Etcher, but commandline only.
+

cmd/diskimg/main.go

@@ -0,0 +1,116 @@
+package main
+
+import (
+	"bytes"
+	"flag"
+	"fmt"
+	"io"
+	"os"
+
+	"git.wntrmute.dev/kyle/goutils/ahash"
+	"git.wntrmute.dev/kyle/goutils/dbg"
+	"git.wntrmute.dev/kyle/goutils/die"
+)
+
+const defaultHashAlgorithm = "sha256"
+
+var (
+	hAlgo      string
+	debug = dbg.New()
+)
+
+
+func openImage(imageFile string) (image *os.File, hash []byte, err error) {
+	image, err = os.Open(imageFile)
+	if err != nil {
+		return
+	}
+
+	hash, err = ahash.SumReader(hAlgo, image)
+	if err != nil {
+		return
+	}
+
+	_, err = image.Seek(0, 0)
+	if err != nil {
+		return
+	}
+
+	debug.Printf("%s  %x\n", imageFile, hash)
+	return
+}
+
+func openDevice(devicePath string) (device *os.File, err error) {
+	fi, err := os.Stat(devicePath)
+	if err != nil {
+		return
+	}
+
+	device, err = os.OpenFile(devicePath, os.O_RDWR|os.O_SYNC, fi.Mode())
+	if err != nil {
+		return
+	}
+
+	return
+}
+
+func main() {
+	flag.StringVar(&hAlgo, "a", defaultHashAlgorithm, "default hash algorithm")
+	flag.BoolVar(&debug.Enabled, "v", false, "enable debug logging")
+	flag.Parse()
+
+	if hAlgo == "list" {
+		fmt.Println("Supported hashing algorithms:")
+		for _, algo := range ahash.SecureHashList() {
+			fmt.Printf("\t- %s\n", algo)
+		}
+		os.Exit(2)
+	}
+
+	if flag.NArg() != 2 {
+		die.With("usage: diskimg image device")
+	}
+
+	imageFile := flag.Arg(0)
+	devicePath := flag.Arg(1)
+
+	debug.Printf("opening image %s for read\n", imageFile)
+	image, hash, err := openImage(imageFile)
+	if image != nil {
+		defer image.Close()
+	}
+	die.If(err)
+
+	debug.Printf("opening device %s for rw\n", devicePath)
+	device, err := openDevice(devicePath)
+	if device != nil {
+		defer device.Close()
+	}
+	die.If(err)
+
+	debug.Printf("writing %s -> %s\n", imageFile, devicePath)
+	n, err := io.Copy(device, image)
+	die.If(err)
+	debug.Printf("wrote %d bytes to %s\n", n, devicePath)
+
+	debug.Printf("syncing %s\n", devicePath)
+	err = device.Sync()
+	die.If(err)
+
+	debug.Println("verifying the image was written successfully")
+	_, err = device.Seek(0, 0)
+	die.If(err)
+
+	deviceHash, err := ahash.SumLimitedReader(hAlgo, device, n)
+	die.If(err)
+
+	if !bytes.Equal(deviceHash, hash) {
+		fmt.Fprintln(os.Stderr, "Hash mismatch:")
+		fmt.Fprintf(os.Stderr, "\t%s: %s\n", imageFile, hash)
+		fmt.Fprintf(os.Stderr, "\t%s: %s\n", devicePath, deviceHash)
+		os.Exit(1)
+	}
+
+	debug.Println("OK")
+	os.Exit(0)
+}

dbg/BUILD.bazel

@@ -9,11 +9,11 @@ go_library(
 
 go_test(
     name = "dbg_test",
+    size = "small",
     srcs = ["dbg_test.go"],
     embed = [":dbg"],
     deps = [
         "//testio",
         "@com_github_stretchr_testify//require",
     ],
-    size = "small",
 )

deps.bzl

@@ -91,6 +91,13 @@ def go_dependencies():
         sum = "h1:Yf1aXowfZ2nuboBsg7iYGLmwsOARdV86pfH3g95wXmE=",
         version = "v1.0.21",
     )
+    go_repository(
+        name = "com_github_hashicorp_go_syslog",
+        importpath = "github.com/hashicorp/go-syslog",
+        sum = "h1:KaodqZuhUoZereWVIYmpUgZysurB1kBLX2j0MwMrUAE=",
+        version = "v1.0.0",
+    )
+
     go_repository(
         name = "com_github_jessevdk_go_flags",
         importpath = "github.com/jessevdk/go-flags",
@@ -304,8 +311,8 @@ def go_dependencies():
     go_repository(
         name = "org_golang_x_crypto",
         importpath = "golang.org/x/crypto",
-        sum = "h1:4yd7jl+vXjalO5ztz6Vc1VADv+S/80LGJmyl1ROJ2AI=",
+        sum = "h1:Qwe1rC8PSniVfAFPFJeyUkB+zcysC3RgJBAGk7eqBEU=",
-        version = "v0.0.0-20201012173705-84dcc777aaee",
+        version = "v0.0.0-20220314234659-1baeb1ce4c0b",
     )
     go_repository(
         name = "org_golang_x_lint",
@@ -316,26 +323,26 @@ def go_dependencies():
     go_repository(
         name = "org_golang_x_net",
         importpath = "golang.org/x/net",
-        sum = "h1:mUVeFHoDKis5nxCAzoAi7E8Ghb86EXh/RK6wtvJIqRY=",
+        sum = "h1:CIJ76btIcR3eFI5EgSo6k1qKw9KJexJuRLI9G7Hp5wE=",
-        version = "v0.0.0-20201010224723-4f7140c49acb",
+        version = "v0.0.0-20211112202133-69e39bad7dc2",
     )
     go_repository(
         name = "org_golang_x_sys",
         importpath = "golang.org/x/sys",
-        sum = "h1:+Nyd8tzPX9R7BWHguqsrbFdRx3WQ/1ib8I44HXV5yTA=",
+        sum = "h1:SrN+KX8Art/Sf4HNj6Zcz06G7VEz+7w9tdXTPOZ7+l4=",
-        version = "v0.0.0-20200930185726-fdedc70b468f",
+        version = "v0.0.0-20210615035016-665e8c7367d1",
     )
     go_repository(
         name = "org_golang_x_term",
         importpath = "golang.org/x/term",
-        sum = "h1:/ZHdbVpdR/jk3g30/d4yUL0JU9kksj8+F/bnQUVLGDM=",
+        sum = "h1:v+OssWQX+hTHEmOBgwxdZxK4zHq3yOs8F9J7mk0PY8E=",
-        version = "v0.0.0-20201117132131-f5c789dd3221",
+        version = "v0.0.0-20201126162022-7de9c90e9dd1",
     )
     go_repository(
         name = "org_golang_x_text",
         importpath = "golang.org/x/text",
-        sum = "h1:cokOdA+Jmi5PJGXLlLllQSgYigAEfHXJAERHVMaCc2k=",
+        sum = "h1:aRYxNxv6iGQlyVaZmk6ZgYEDa+Jg18DxebPSrd6bg1M=",
-        version = "v0.3.3",
+        version = "v0.3.6",
     )
     go_repository(
         name = "org_golang_x_tools",

go.mod

@@ -4,12 +4,13 @@ go 1.20
 
 require (
 	github.com/cloudflare/cfssl v1.5.0
+	github.com/hashicorp/go-syslog v1.0.0
 	github.com/kr/text v0.2.0
 	github.com/pkg/errors v0.9.1
 	github.com/pkg/sftp v1.12.0
 	github.com/stretchr/testify v1.6.1
-	golang.org/x/crypto v0.0.0-20201012173705-84dcc777aaee
+	golang.org/x/crypto v0.0.0-20220314234659-1baeb1ce4c0b
-	golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f
+	golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1
 	gopkg.in/yaml.v2 v2.4.0
 )
 

go.sum

@@ -18,6 +18,8 @@ github.com/go-sql-driver/mysql v1.4.0/go.mod h1:zAC/RDZ24gD3HViQzih4MyKcchzm+sOG
 github.com/golang/protobuf v1.3.1/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
 github.com/google/certificate-transparency-go v1.0.21 h1:Yf1aXowfZ2nuboBsg7iYGLmwsOARdV86pfH3g95wXmE=
 github.com/google/certificate-transparency-go v1.0.21/go.mod h1:QeJfpSbVSfYc7RgB3gJFj9cbuQMMchQxrWXz8Ruopmg=
+github.com/hashicorp/go-syslog v1.0.0 h1:KaodqZuhUoZereWVIYmpUgZysurB1kBLX2j0MwMrUAE=
+github.com/hashicorp/go-syslog v1.0.0/go.mod h1:qPfqrKkXGihmCqbJM2mZgkZGvKG1dFdvsLplgctolz4=
 github.com/jessevdk/go-flags v1.4.0/go.mod h1:4FA24M0QyGHXBuZZK/XkWh8h0e1EYbRYJSGM75WSRxI=
 github.com/jmhodges/clock v0.0.0-20160418191101-880ee4c33548/go.mod h1:hGT6jSUVzF6no3QaDSMLGLEHtHSBSefs+MgcDWnmhmo=
 github.com/jmoiron/sqlx v1.2.0/go.mod h1:1FEQNm3xlJgrMD+FBdI9+xvCksHtbpVBBw5dYhBSsks=
@@ -70,8 +72,9 @@ golang.org/x/crypto v0.0.0-20190701094942-4def268fd1a4/go.mod h1:yigFU9vqHzYiE8U
 golang.org/x/crypto v0.0.0-20200124225646-8b5121be2f68/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/crypto v0.0.0-20200820211705-5c72a883971a/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
-golang.org/x/crypto v0.0.0-20201012173705-84dcc777aaee h1:4yd7jl+vXjalO5ztz6Vc1VADv+S/80LGJmyl1ROJ2AI=
 golang.org/x/crypto v0.0.0-20201012173705-84dcc777aaee/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
+golang.org/x/crypto v0.0.0-20220314234659-1baeb1ce4c0b h1:Qwe1rC8PSniVfAFPFJeyUkB+zcysC3RgJBAGk7eqBEU=
+golang.org/x/crypto v0.0.0-20220314234659-1baeb1ce4c0b/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4=
 golang.org/x/lint v0.0.0-20190930215403-16217165b5de/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc=
 golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
@@ -81,8 +84,10 @@ golang.org/x/net v0.0.0-20201010224723-4f7140c49acb/go.mod h1:sp8m0HH+o8qH0wwXwY
 golang.org/x/sys v0.0.0-20180905080454-ebe1bf3edb33/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f h1:+Nyd8tzPX9R7BWHguqsrbFdRx3WQ/1ib8I44HXV5yTA=
 golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1 h1:SrN+KX8Art/Sf4HNj6Zcz06G7VEz+7w9tdXTPOZ7+l4=
+golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1 h1:v+OssWQX+hTHEmOBgwxdZxK4zHq3yOs8F9J7mk0PY8E=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=

lib/BUILD.bazel

@@ -110,8 +110,8 @@ go_library(
 
 go_test(
     name = "lib_test",
+    size = "small",
     srcs = ["lib_test.go"],
     embed = [":lib"],
     deps = ["//assert"],
-    size = "small",
 )

logging/BUILD.bazel

@@ -15,10 +15,10 @@ go_library(
 
 go_test(
     name = "logging_test",
+    size = "small",
     srcs = [
         "example_test.go",
         "log_test.go",
     ],
     embed = [":logging"],
-    size = "small",
 )

mwc/BUILD.bazel

@@ -9,11 +9,11 @@ go_library(
 
 go_test(
     name = "mwc_test",
+    size = "small",
     srcs = ["mwc_test.go"],
     embed = [":mwc"],
     deps = [
         "//assert",
         "//testio",
     ],
-    size = "small",
 )

rand/BUILD.bazel

@@ -9,7 +9,7 @@ go_library(
 
 go_test(
     name = "rand_test",
+    size = "small",
     srcs = ["rand_test.go"],
     embed = [":rand"],
-    size = "small",
 )

sbuf/BUILD.bazel

@@ -9,8 +9,8 @@ go_library(
 
 go_test(
     name = "sbuf_test",
+    size = "small",
     srcs = ["sbuf_test.go"],
     embed = [":sbuf"],
     deps = ["@org_golang_x_crypto//nacl/box"],
-    size = "small",
 )

seekbuf/BUILD.bazel

@@ -1,4 +1,4 @@
-load("@io_bazel_rules_go//go:def.bzl", "go_library")
+load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
 
 go_library(
     name = "seekbuf",
@@ -6,3 +6,11 @@ go_library(
     importpath = "git.wntrmute.dev/kyle/goutils/seekbuf",
     visibility = ["//visibility:public"],
 )
+
+go_test(
+    name = "seekbuf_test",
+    size = "small",
+    srcs = ["seekbuf_test.go"],
+    embed = [":seekbuf"],
+    deps = ["//assert"],
+)

seekbuf/seekbuf.go

@@ -1,3 +1,4 @@
+// seekbuf implements a read-seekable buffer.
 package seekbuf
 
 import "io"
@@ -40,7 +41,7 @@ func (b *Buffer) Seek(pos int) {
 
 // Rewind resets the read pointer to 0.
 func (b *Buffer) Rewind() {
-	b.pos = 0
+	b.Seek(0)
 }
 
 // Close clears all the data out of the buffer and sets the read position to 0.
@@ -49,3 +50,8 @@ func (b *Buffer) Close() error {
 	b.pos = 0
 	return nil
 }
+
+// Len returns the length of data remaining to be read.
+func (b *Buffer) Len() int {
+	return len(b.data[b.pos:])
+}

seekbuf/seekbuf_test.go

@@ -0,0 +1,39 @@
+package seekbuf
+
+import (
+	"fmt"
+	"testing"
+
+	"git.wntrmute.dev/kyle/goutils/assert"
+)
+
+func TestSeeking(t *testing.T) {
+	partA := []byte("hello, ")
+	partB := []byte("world!")
+
+	buf := New(partA)
+	assert.BoolT(t, buf.Len() == len(partA), fmt.Sprintf("on init: have length %d, want length %d", buf.Len(), len(partA)))
+
+	b := make([]byte, 32)
+
+	n, err := buf.Read(b)
+	assert.NoErrorT(t, err)
+	assert.BoolT(t, buf.Len() == 0, fmt.Sprintf("after reading 1: have length %d, want length 0", buf.Len()))
+	assert.BoolT(t, n == len(partA), fmt.Sprintf("after reading 2: have length %d, want length %d", n, len(partA)))
+
+	n, err = buf.Write(partB)
+	assert.NoErrorT(t, err)
+	assert.BoolT(t, n == len(partB), fmt.Sprintf("after writing: have length %d, want length %d", n, len(partB)))
+
+	n, err = buf.Read(b)
+	assert.NoErrorT(t, err)
+	assert.BoolT(t, buf.Len() == 0, fmt.Sprintf("after rereading 1: have length %d, want length 0", buf.Len()))
+	assert.BoolT(t, n == len(partB), fmt.Sprintf("after rereading 2: have length %d, want length %d", n, len(partB)))
+
+	partsLen := len(partA) + len(partB)
+	buf.Rewind()
+	assert.BoolT(t, buf.Len() == partsLen, fmt.Sprintf("after rewinding: have length %d, want length %d", buf.Len(), partsLen))
+
+	buf.Close()
+	assert.BoolT(t, buf.Len() == 0, fmt.Sprintf("after closing, have length %d, want length 0", buf.Len()))
+}

syslog/BUILD.bazel

@@ -0,0 +1,17 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "log",
+    srcs = ["logger.go"],
+    importpath = "git.wntrmute.dev/kyle/kdhcp/log",
+    visibility = ["//visibility:public"],
+    deps = ["@com_github_hashicorp_go_syslog//:go-syslog"],
+)
+
+go_library(
+    name = "syslog",
+    srcs = ["logger.go"],
+    importpath = "git.wntrmute.dev/kyle/goutils/syslog",
+    visibility = ["//visibility:public"],
+    deps = ["@com_github_hashicorp_go_syslog//:go-syslog"],
+)

syslog/logger.go

@@ -0,0 +1,257 @@
+// syslog is a syslog-type facility for logging.
+package syslog
+
+import (
+	"fmt"
+	"os"
+	"strings"
+	"time"
+
+	gsyslog "github.com/hashicorp/go-syslog"
+)
+
+type logger struct {
+	l gsyslog.Syslogger
+	p gsyslog.Priority
+}
+
+func (log *logger) printf(p gsyslog.Priority, format string, args ...interface{}) {
+	if !strings.HasSuffix(format, "\n") {
+		format += "\n"
+	}
+
+	if p <= log.p {
+		fmt.Printf("%s [%s] ", prioritiev[p], timestamp())
+		fmt.Printf(format, args...)
+	}
+
+	if log.l != nil {
+		log.l.WriteLevel(p, []byte(fmt.Sprintf(format, args...)))
+	}
+}
+
+func (log *logger) print(p gsyslog.Priority, args ...interface{}) {
+	if p <= log.p {
+		fmt.Printf("%s [%s] ", prioritiev[p], timestamp())
+		fmt.Print(args...)
+	}
+
+	if log.l != nil {
+		log.l.WriteLevel(p, []byte(fmt.Sprint(args...)))
+	}
+}
+
+func (log *logger) println(p gsyslog.Priority, args ...interface{}) {
+	if p <= log.p {
+		fmt.Printf("%s [%s] ", prioritiev[p], timestamp())
+		fmt.Println(args...)
+	}
+
+	if log.l != nil {
+		log.l.WriteLevel(p, []byte(fmt.Sprintln(args...)))
+	}
+}
+
+func (log *logger) adjustPriority(level string) error {
+	priority, ok := priorities[level]
+	if !ok {
+		return fmt.Errorf("log: unknown priority %s", level)
+	}
+
+	log.p = priority
+	return nil
+}
+
+var log = &logger{p: gsyslog.LOG_WARNING}
+
+var priorities = map[string]gsyslog.Priority{
+	"EMERG":   gsyslog.LOG_EMERG,
+	"ALERT":   gsyslog.LOG_ALERT,
+	"CRIT":    gsyslog.LOG_CRIT,
+	"ERR":     gsyslog.LOG_ERR,
+	"WARNING": gsyslog.LOG_WARNING,
+	"NOTICE":  gsyslog.LOG_NOTICE,
+	"INFO":    gsyslog.LOG_INFO,
+	"DEBUG":   gsyslog.LOG_DEBUG,
+}
+
+var prioritiev = map[gsyslog.Priority]string{
+	gsyslog.LOG_EMERG:   "EMERG",
+	gsyslog.LOG_ALERT:   "ALERT",
+	gsyslog.LOG_CRIT:    "CRIT",
+	gsyslog.LOG_ERR:     "ERR",
+	gsyslog.LOG_WARNING: "WARNING",
+	gsyslog.LOG_NOTICE:  "NOTICE",
+	gsyslog.LOG_INFO:    "INFO",
+	gsyslog.LOG_DEBUG:   "DEBUG",
+}
+
+func timestamp() string {
+	return time.Now().Format("2006-01-02 15:04:05 MST")
+}
+
+type Options struct {
+	Level       string
+	Tag         string
+	Facility    string
+	WriteSyslog bool
+}
+
+// DefaultOptions returns a sane set of defaults for syslog, using the program
+// name as the tag name. withSyslog controls whether logs should be sent to
+// syslog, too.
+func DefaultOptions(tag string, withSyslog bool) {
+	if tag == "" {
+		tag = os.Args[0]
+	}
+
+	return &DefaultOptions{
+		Level:       "WARNING",
+		Tag:         tag,
+		Facility:    "daemon",
+		WriteSyslog: withSyslog,
+	}
+}
+
+// DefaultDefaultOptions returns a sane set of debug defaults for syslog,
+// using the program name as the tag name. withSyslog controls whether logs
+// should be sent to syslog, too.
+func DefaultDebugOptions(tag string, withSyslog bool) {
+	if tag == "" {
+		tag = os.Args[0]
+	}
+
+	return &DefaultOptions{
+		Level:       "DEBUG",
+		Facility:    "daemon",
+		WriteSyslog: withSyslog,
+	}
+}
+
+func Setup(opts *Options) error {
+	priority, ok := priorities[opts.Level]
+	if !ok {
+		return fmt.Errorf("log: unknown priority %s", level)
+	}
+
+	log.p = priority
+
+	var err error
+	log.l, err = gsyslog.NewLogger(priority, opts.Facility, opts.Tag)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func Debug(args ...interface{}) {
+	log.print(gsyslog.LOG_DEBUG, args...)
+}
+
+func Info(args ...interface{}) {
+	log.print(gsyslog.LOG_INFO, args...)
+}
+
+func Notice(args ...interface{}) {
+	log.print(gsyslog.LOG_NOTICE, args...)
+}
+
+func Warning(args ...interface{}) {
+	log.print(gsyslog.LOG_WARNING, args...)
+}
+
+func Err(args ...interface{}) {
+	log.print(gsyslog.LOG_ERR, args...)
+}
+
+func Crit(args ...interface{}) {
+	log.print(gsyslog.LOG_CRIT, args...)
+}
+
+func Alert(args ...interface{}) {
+	log.print(gsyslog.LOG_ALERT, args...)
+}
+
+func Emerg(args ...interface{}) {
+	log.print(gsyslog.LOG_EMERG, args...)
+}
+
+func Debugln(args ...interface{}) {
+	log.println(gsyslog.LOG_DEBUG, args...)
+}
+
+func Infoln(args ...interface{}) {
+	log.println(gsyslog.LOG_INFO, args...)
+}
+
+func Noticeln(args ...interface{}) {
+	log.println(gsyslog.LOG_NOTICE, args...)
+}
+
+func Warningln(args ...interface{}) {
+	log.print(gsyslog.LOG_WARNING, args...)
+}
+
+func Errln(args ...interface{}) {
+	log.println(gsyslog.LOG_ERR, args...)
+}
+
+func Critln(args ...interface{}) {
+	log.println(gsyslog.LOG_CRIT, args...)
+}
+
+func Alertln(args ...interface{}) {
+	log.println(gsyslog.LOG_ALERT, args...)
+}
+
+func Emergln(args ...interface{}) {
+	log.println(gsyslog.LOG_EMERG, args...)
+}
+
+func Debugf(format string, args ...interface{}) {
+	log.printf(gsyslog.LOG_DEBUG, format, args...)
+}
+
+func Infof(format string, args ...interface{}) {
+	log.printf(gsyslog.LOG_INFO, format, args...)
+}
+
+func Noticef(format string, args ...interface{}) {
+	log.printf(gsyslog.LOG_NOTICE, format, args...)
+}
+
+func Warningf(format string, args ...interface{}) {
+	log.printf(gsyslog.LOG_WARNING, format, args...)
+}
+
+func Errf(format string, args ...interface{}) {
+	log.printf(gsyslog.LOG_ERR, format, args...)
+}
+
+func Critf(format string, args ...interface{}) {
+	log.printf(gsyslog.LOG_CRIT, format, args...)
+}
+
+func Alertf(format string, args ...interface{}) {
+	log.printf(gsyslog.LOG_ALERT, format, args...)
+}
+
+func Emergf(format string, args ...interface{}) {
+	log.printf(gsyslog.LOG_EMERG, format, args...)
+	os.Exit(1)
+}
+
+func Fatal(args ...interface{}) {
+	log.println(gsyslog.LOG_ERR, args...)
+	os.Exit(1)
+}
+
+func Fatalf(format string, args ...interface{}) {
+	log.printf(gsyslog.LOG_ERR, format, args...)
+	os.Exit(1)
+}
+
+func ChangePriority(level string) error {
+	return log.adjustPriority(level)
+}

testio/BUILD.bazel

@@ -9,7 +9,7 @@ go_library(
 
 go_test(
     name = "testio_test",
+    size = "small",
     srcs = ["testio_test.go"],
     embed = [":testio"],
-    size = "small",
 )