Merge pull request #163 from FedeDP/new/go_embed_templates

new(pkg): use go:embed for templates, removing them from source code and putting them in their own subfolder

README.md

@@ -399,7 +399,17 @@ func (v archLinux) Script(c Config) (string, error) {
 ```
 
 Essentially, the `Script` function that you are implementing will need to return a string containing
-a `bash` script that will be executed by driverkit at build time.
+a `bash` script that will be executed by driverkit at build time. 
+
+Under `pkg/driverbuilder/builder/templates` folder, you can find all the template scripts for the supported builders. 
+Adding a new template there and using `go:embed` to include it in your builder, allows leaner code 
+without mixing up templates and builder logic. 
+For example:
+
+```go
+//go:embed templates/archlinux.sh
+var archlinuxTemplate string
+```
 
 Depending on how the distro works, the script will need to fetch the kernel headers for it at the specific kernel version specified
 in the `Config` struct at `c.Build.KernelVersion`.

pkg/driverbuilder/builder/amazonlinux.go

@@ -5,6 +5,7 @@ import (
  "bytes"
  "compress/bzip2"
  "compress/gzip"
+ _ "embed"
  "fmt"
  "io"
  "io/ioutil"
@@ -22,6 +23,9 @@ import (
  logger "github.com/sirupsen/logrus"
 )
 
+//go:embed templates/amazonlinux.sh
+var amazonlinuxTemplate string
+
 type amazonBuilder interface {
  Builder
  repos() []string
@@ -54,51 +58,6 @@ func init() {
  BuilderByTarget[TargetTypeAmazonLinux] = &amazonlinux{}
 }
 
-const amazonlinuxTemplate = `
-#!/bin/bash
-set -xeuo pipefail
-
-rm -Rf {{ .DriverBuildDir }}
-mkdir {{ .DriverBuildDir }}
-rm -Rf /tmp/module-download
-mkdir -p /tmp/module-download
-
-curl --silent -SL {{ .ModuleDownloadURL }} | tar -xzf - -C /tmp/module-download
-mv /tmp/module-download/*/driver/* {{ .DriverBuildDir }}
-
-cp /driverkit/module-Makefile {{ .DriverBuildDir }}/Makefile
-bash /driverkit/fill-driver-config.sh {{ .DriverBuildDir }}
-
-# Fetch the kernel
-mkdir /tmp/kernel-download
-cd /tmp/kernel-download
-{{ range $url := .KernelDownloadURLs }}
-curl --silent -o kernel.rpm -SL {{ $url }}
-rpm2cpio kernel.rpm | cpio --extract --make-directories
-rm -rf kernel.rpm
-{{ end }}
-rm -Rf /tmp/kernel
-mkdir -p /tmp/kernel
-mv usr/src/kernels/*/* /tmp/kernel
-
-{{ if .BuildModule }}
-# Build the kernel module
-cd {{ .DriverBuildDir }}
-
-make KERNELDIR=/tmp/kernel CC=/usr/bin/gcc LD=/usr/bin/ld.bfd CROSS_COMPILE=""
-mv {{ .ModuleDriverName }}.ko {{ .ModuleFullPath }}
-# Print results
-modinfo {{ .ModuleFullPath }}
-{{ end }}
-
-{{ if .BuildProbe }}
-# Build the eBPF probe
-cd {{ .DriverBuildDir }}/bpf
-make LLC=/usr/bin/llc-{{ .LLVMVersion }} CLANG=/usr/bin/clang-{{ .LLVMVersion }} CC=/usr/bin/gcc KERNELDIR=/tmp/kernel
-ls -l probe.o
-{{ end }}
-`
-
 type amazonlinuxTemplateData struct {
  DriverBuildDir string
  ModuleDownloadURL string

pkg/driverbuilder/builder/centos.go

@@ -2,12 +2,16 @@ package builder
 
 import (
  "bytes"
+ _ "embed"
  "fmt"
  "text/template"
 
  "github.com/falcosecurity/driverkit/pkg/kernelrelease"
 )
 
+//go:embed templates/centos.sh
+var centosTemplate string
+
 // TargetTypeCentos identifies the Centos target.
 const TargetTypeCentos Type = "centos"
 
@@ -179,51 +183,6 @@ type centosTemplateData struct {
  BuildProbe bool
 }
 
-const centosTemplate = `
-#!/bin/bash
-set -xeuo pipefail
-
-rm -Rf {{ .DriverBuildDir }}
-mkdir {{ .DriverBuildDir }}
-rm -Rf /tmp/module-download
-mkdir -p /tmp/module-download
-
-curl --silent -SL {{ .ModuleDownloadURL }} | tar -xzf - -C /tmp/module-download
-mv /tmp/module-download/*/driver/* {{ .DriverBuildDir }}
-
-cp /driverkit/module-Makefile {{ .DriverBuildDir }}/Makefile
-bash /driverkit/fill-driver-config.sh {{ .DriverBuildDir }}
-
-# Fetch the kernel
-mkdir /tmp/kernel-download
-cd /tmp/kernel-download
-curl --silent -o kernel-devel.rpm -SL {{ .KernelDownloadURL }}
-rpm2cpio kernel-devel.rpm | cpio --extract --make-directories
-rm -Rf /tmp/kernel
-mkdir -p /tmp/kernel
-mv usr/src/kernels/*/* /tmp/kernel
-
-# Change current gcc
-ln -sf /usr/bin/gcc-{{ .GCCVersion }} /usr/bin/gcc
-
-{{ if .BuildModule }}
-# Build the module
-cd {{ .DriverBuildDir }}
-make KERNELDIR=/tmp/kernel
-mv {{ .ModuleDriverName }}.ko {{ .ModuleFullPath }}
-strip -g {{ .ModuleFullPath }}
-# Print results
-modinfo {{ .ModuleFullPath }}
-{{ end }}
-
-{{ if .BuildProbe }}
-# Build the eBPF probe
-cd {{ .DriverBuildDir }}/bpf
-make LLC=/usr/bin/llc-7 CLANG=/usr/bin/clang-7 CC=/usr/bin/gcc KERNELDIR=/tmp/kernel
-ls -l probe.o
-{{ end }}
-`
-
 func centosGccVersionFromKernelRelease(kr kernelrelease.KernelRelease) string {
  switch kr.Version {
  case 3:

pkg/driverbuilder/builder/debian.go

@@ -2,6 +2,7 @@ package builder
 
 import (
  "bytes"
+ _ "embed"
  "fmt"
  "io/ioutil"
  "net/http"
@@ -12,6 +13,9 @@ import (
  "github.com/falcosecurity/driverkit/pkg/kernelrelease"
 )
 
+//go:embed templates/debian.sh
+var debianTemplate string
+
 // TargetTypeDebian identifies the Debian target.
 const TargetTypeDebian Type = "debian"
 
@@ -102,59 +106,6 @@ type debianTemplateData struct {
  LLVMVersion string
 }
 
-const debianTemplate = `
-#!/bin/bash
-set -xeuo pipefail
-
-rm -Rf {{ .DriverBuildDir }}
-mkdir {{ .DriverBuildDir }}
-rm -Rf /tmp/module-download
-mkdir -p /tmp/module-download
-
-curl --silent -SL {{ .ModuleDownloadURL }} | tar -xzf - -C /tmp/module-download
-mv /tmp/module-download/*/driver/* {{ .DriverBuildDir }}
-
-cp /driverkit/module-Makefile {{ .DriverBuildDir }}/Makefile
-bash /driverkit/fill-driver-config.sh {{ .DriverBuildDir }}
-
-# Fetch the kernel
-mkdir /tmp/kernel-download
-cd /tmp/kernel-download
-{{ range $url := .KernelDownloadURLS }}
-curl --silent -o kernel.deb -SL {{ $url }}
-ar x kernel.deb
-tar -xvf data.tar.xz
-{{ end }}
-ls -la /tmp/kernel-download
-
-cd /tmp/kernel-download/
-
-cp -r usr/* /usr
-cp -r lib/* /lib
-
-cd /usr/src
-sourcedir=$(find . -type d -name "linux-headers-*%s" | head -n 1 | xargs readlink -f)
-
-ls -la $sourcedir
-
-{{ if .BuildModule }}
-# Build the module
-cd {{ .DriverBuildDir }}
-make CC=/usr/bin/gcc-8 KERNELDIR=$sourcedir
-mv {{ .ModuleDriverName }}.ko {{ .ModuleFullPath }}
-strip -g {{ .ModuleFullPath }}
-# Print results
-modinfo {{ .ModuleFullPath }}
-{{ end }}
-
-{{ if .BuildProbe }}
-# Build the eBPF probe
-cd {{ .DriverBuildDir }}/bpf
-make LLC=/usr/bin/llc-{{ .LLVMVersion }} CLANG=/usr/bin/clang-{{ .LLVMVersion }} CC=/usr/bin/gcc-8 KERNELDIR=$sourcedir
-ls -l probe.o
-{{ end }}
-`
-
 func debianHeadersURLFromRelease(kr kernelrelease.KernelRelease) ([]string, error) {
  baseURLS := []string{
  "http://security-cdn.debian.org/pool/main/l/linux/",

pkg/driverbuilder/builder/flatcar.go

@@ -2,6 +2,7 @@ package builder
 
 import (
  "bytes"
+ _ "embed"
  "fmt"
  "io/ioutil"
  "net/http"
@@ -11,6 +12,9 @@ import (
  "github.com/falcosecurity/driverkit/pkg/kernelrelease"
 )
 
+//go:embed templates/flatcar.sh
+var flatcarTemplate string
+
 // TargetTypeFlatcar identifies the Flatcar target.
 const TargetTypeFlatcar Type = "flatcar"
 
@@ -169,57 +173,6 @@ type flatcarTemplateData struct {
  BuildProbe bool
 }
 
-const flatcarTemplate = `
-#!/bin/bash
-set -xeuo pipefail
-
-rm -Rf {{ .DriverBuildDir }}
-mkdir {{ .DriverBuildDir }}
-rm -Rf /tmp/module-download
-mkdir -p /tmp/module-download
-
-curl --silent -SL {{ .ModuleDownloadURL }} | tar -xzf - -C /tmp/module-download
-mv /tmp/module-download/*/driver/* {{ .DriverBuildDir }}
-
-cp /driverkit/module-Makefile {{ .DriverBuildDir }}/Makefile
-bash /driverkit/fill-driver-config.sh {{ .DriverBuildDir }}
-
-# Fetch the kernel
-mkdir /tmp/kernel-download
-cd /tmp/kernel-download
-curl --silent -SL {{ .KernelDownloadURL }} | tar -Jxf - -C /tmp/kernel-download
-rm -Rf /tmp/kernel
-mkdir -p /tmp/kernel
-mv /tmp/kernel-download/*/* /tmp/kernel
-
-# Change current gcc
-ln -sf /usr/bin/gcc-{{ .GCCVersion }} /usr/bin/gcc
-
-curl --silent -o /tmp/kernel.config -SL {{ .KernelConfigURL }}
-
-cd /tmp/kernel
-sed -i -e 's|^\(EXTRAVERSION =\).*|\1 -flatcar|' Makefile
-make KCONFIG_CONFIG=/tmp/kernel.config oldconfig
-make KCONFIG_CONFIG=/tmp/kernel.config modules_prepare
-
-{{ if .BuildModule }}
-# Build the module
-cd {{ .DriverBuildDir }}
-make KERNELDIR=/tmp/kernel
-mv {{ .ModuleDriverName }}.ko {{ .ModuleFullPath }}
-strip -g {{ .ModuleFullPath }}
-# Print results
-modinfo {{ .ModuleFullPath }}
-{{ end }}
-
-{{ if .BuildProbe }}
-# Build the eBPF probe
-cd {{ .DriverBuildDir }}/bpf
-make LLC=/usr/bin/llc-12 CLANG=/usr/bin/clang-12 CC=/usr/bin/gcc KERNELDIR=/tmp/kernel
-ls -l probe.o
-{{ end }}
-`
-
 func flatcarGccVersion(gccVersion string) string {
  // reuse kernelrelease version parsing for gcc
  gv := kernelrelease.FromString(gccVersion)

pkg/driverbuilder/builder/redhat.go

@@ -2,10 +2,14 @@ package builder
 
 import (
  "bytes"
+ _ "embed"
  "github.com/falcosecurity/driverkit/pkg/kernelrelease"
  "text/template"
 )
 
+//go:embed templates/redhat.sh
+var redhatTemplate string
+
 // TargetTypeRedhat identifies the redhat target.
 const TargetTypeRedhat Type = "redhat"
 
@@ -27,57 +31,13 @@ type redhatTemplateData struct {
  BuildProbe bool
 }
 
-const redhatTemplate = `
-#!/bin/bash
-set -xeuo pipefail
-
-rm -Rf {{ .DriverBuildDir }}
-mkdir {{ .DriverBuildDir }}
-rm -Rf /tmp/module-download
-mkdir -p /tmp/module-download
-
-curl --silent -SL {{ .ModuleDownloadURL }} | tar -xzf - -C /tmp/module-download
-mv /tmp/module-download/*/driver/* {{ .DriverBuildDir }}
-
-cp /driverkit/module-Makefile {{ .DriverBuildDir }}/Makefile
-bash /driverkit/fill-driver-config.sh {{ .DriverBuildDir }}
-
-# Fetch the kernel
-rm -Rf /tmp/kernel-download
-mkdir /tmp/kernel-download
-cd /tmp/kernel-download
-yum install -y --downloadonly --downloaddir=/tmp/kernel-download kernel-devel-0:{{ .KernelPackage }}
-rpm2cpio kernel-devel-{{ .KernelPackage }}.rpm | cpio --extract --make-directories
-
-rm -Rf /tmp/kernel
-mkdir -p /tmp/kernel
-mv usr/src/kernels/*/* /tmp/kernel
-
-{{ if .BuildModule }}
-# Build the module
-cd {{ .DriverBuildDir }}
-make KERNELDIR=/tmp/kernel
-mv {{ .ModuleDriverName }}.ko {{ .ModuleFullPath }}
-strip -g {{ .ModuleFullPath }}
-# Print results
-modinfo {{ .ModuleFullPath }}
-{{ end }}
-
-{{ if .BuildProbe }}
-# Build the eBPF probe
-cd {{ .DriverBuildDir }}/bpf
-make LLC=/usr/bin/llc CLANG=/usr/bin/clang CC=/usr/bin/gcc KERNELDIR=/tmp/kernel
-ls -l probe.o
-{{ end }}
-`
-
 func (v redhat) Script(cfg Config, kr kernelrelease.KernelRelease) (string, error) {
  t := template.New(string(TargetTypeRedhat))
  parsed, err := t.Parse(redhatTemplate)
  if err != nil {
  return "", err
  }
- 
+
  td := redhatTemplateData{
  DriverBuildDir: DriverDirectory,
  KernelPackage: kr.Fullversion + kr.FullExtraversion,