Add slim-sprig functions to template language

slim-sprig is a lightweight library containing a number of useful helper
functions which are useful to use in go templates. Include it in debos
so we can use the functions in recipes.

Signed-off-by: Christopher Obbard <[email protected]>

actions/recipe.go

@@ -30,10 +30,11 @@ Comments are allowed and should be prefixed with '#' symbol.
      property2: {{$Var}}
 
 
-The following custom template functions are available
+The following custom template functions are available:
 
 - sector: Returns the argument * 512 (convential sector size) e.g. `{{ sector 64 }}`
 - escape: Shell escape the  argument `{{ escape $var }}`
+- functions from [slim-sprig](https://go-task.github.io/slim-sprig/)
 
 Mandatory properties for recipe:
 
@@ -81,6 +82,7 @@ import (
 	"github.com/go-debos/debos"
 	"gopkg.in/yaml.v2"
 	"github.com/alessio/shellescape"
+	"github.com/go-task/slim-sprig/v3"
 	"path"
 	"text/template"
 	"log"
@@ -246,6 +248,9 @@ func (r *Recipe) Parse(file string, printRecipe bool, dump bool, templateVars ..
 	}
 	t.Funcs(funcs)
 
+	/* Add slim-sprig functions to template language */
+	t.Funcs(sprig.FuncMap())
+
 	if _, err := t.ParseFiles(file); err != nil {
 		return err
 	}

go.mod

@@ -7,10 +7,11 @@ require (
 	github.com/alessio/shellescape v1.4.2
 	github.com/docker/go-units v0.5.0
 	github.com/go-debos/fakemachine v0.0.8
+	github.com/go-task/slim-sprig/v3 v3.0.0
 	github.com/google/uuid v1.4.0
 	github.com/jessevdk/go-flags v1.5.0
 	github.com/sjoerdsimons/ostree-go v0.0.0-20201014091107-8fae757256f8
-	github.com/stretchr/testify v1.8.2
+	github.com/stretchr/testify v1.8.4
 	gopkg.in/freddierice/go-losetup.v1 v1.0.0-20170407175016-fc9adea44124
 	gopkg.in/yaml.v2 v2.4.0
 )

go.sum

@@ -9,6 +9,8 @@ github.com/docker/go-units v0.5.0 h1:69rxXcBk27SvSaaxTtLh/8llcHD8vYHT7WSdRZ/jvr4
 github.com/docker/go-units v0.5.0/go.mod h1:fgPhTUdO+D/Jk86RDLlptpiXQzgHJF7gydDDbaIK4Dk=
 github.com/go-debos/fakemachine v0.0.8 h1:qCQLQ+dKLQE4ZMbJLMP+vnSrNiFuIBJjP5pnbLT4xpg=
 github.com/go-debos/fakemachine v0.0.8/go.mod h1:65Ym4PfsS5ayO0trZ8UoJZFriIBLqbwjrcMKqoaUQoQ=
+github.com/go-task/slim-sprig/v3 v3.0.0 h1:sUs3vkvUymDpBKi3qH1YSqBQk9+9D/8M2mN1vB6EwHI=
+github.com/go-task/slim-sprig/v3 v3.0.0/go.mod h1:W848ghGpv3Qj3dhTPRyJypKRiqCdHZiAzKg9hl15HA8=
 github.com/google/uuid v1.4.0 h1:MtMxsa51/r9yyhkyLsVeVt0B+BGQZzpQiTQ4eHZ8bc4=
 github.com/google/uuid v1.4.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/jessevdk/go-flags v1.5.0 h1:1jKYvbxEjfUl0fmqTCOfonvskHHXMjBySTLW4y9LFvc=
@@ -25,8 +27,8 @@ github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpE
 github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
 github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
-github.com/stretchr/testify v1.8.2 h1:+h33VjcLVPDHtOdpUCuF+7gSuG3yGIftsP1YvFihtJ8=
-github.com/stretchr/testify v1.8.2/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
+github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
+github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
 github.com/surma/gocpio v1.1.0 h1:RUWT+VqJ8GSodSv7Oh5xjIxy7r24CV1YvothHFfPxcQ=
 github.com/surma/gocpio v1.1.0/go.mod h1:zaLNaN+EDnfSnNdWPJJf9OZxWF817w5dt8JNzF9LCVI=
 github.com/ulikunitz/xz v0.5.11 h1:kpFauv27b6ynzBNT/Xy+1k+fK4WswhN/6PN5WhFAGw8=