tf

tf - Template File

Template Dockerfile or configuration using GO text template (http://golang.org/pkg/text/template/) in Bash with input from YAML, JSON, TOML, Etcd, REST or MySQL.

Usage

Usage:
  tf [OPTIONS]

Application Options:
  -v, --verbose         Verbose
      --version         Version
  -c, --config=         YAML, TOML or JSON config file
  -i, --input=          Input, defaults to using YAML
  -F, --input-format=   Data serialization format YAML, TOML or JSON (YAML)
  -f, --input-file=     Input file, data serialization format used is based on the file extension
  -t, --template=       Template file
  -l, --template-lang   Template language text or pongo2 (pongo2)
  -o, --output=         Output file (STDOUT)
  -p, --permission=     File permissions in octal (644)
  -O, --owner=          File Owner
      --etcd-host=      Etcd Host
      --etcd-port=      Etcd Port (2379)
      --etcd-dir=       Etcd Dir (/)
      --http-url=       HTTP Url
      --http-header=    HTTP Header (Accept: application/json)
      --http-format=    HTTP Format (JSON)
      --mysql-user=     MySQL user
      --mysql-password= MySQL password
      --mysql-host=     MySQL host
      --mysql-port=     MySQL port (3306)
      --mysql-database= MySQL database
      --mysql-query=    MySQL query

Help Options:
  -h, --help            Show this help message

Input will have it's own namespace such as Arg, File, Env, Etcd. you can also get this by:

echo '{{ keys . }}' | tf -l text

Argument input will also be in the root scope for convenience.

Configuration file

Configuration file is also a template i.e. you can use .Env and .Arg for customizing inputs.

Defaults

Example:

[defaults]
mysql_user = "test"
mysql_pass = "test"
mysql_host = "mysql.example.com"
mysql_port = 3306
mysql_database = "test"

Inputs

Generic

Specific

Example with Etcd

IP=localhost

If you're using Boot2Docker or docker-machine:

IP=$(echo ${DOCKER_HOST##tcp://} | awk -F: '{ print $1}')

docker run -d --name etcd -p 4001:4001 coreos/etcd:v0.4.6
curl -L http://${IP}:4001/v2/keys/hosts/host1.example.com/serialno -XPUT -d value="abc123"
curl -L http://${IP}:4001/v2/keys/hosts/host2.example.com/serialno -XPUT -d value="def456"
curl -L http://${IP}:4001/v2/keys/hosts/host3.example.com/serialno -XPUT -d value="fgh789"
printf '{{ range $k, $e := .Etcd }}| {{ $k | lalign 20 }} | {{ $e.serialno | lalign 10 }} |\n{{end}}' | \
tf --etcd-host ${IP} --etcd-port 4001 --etcd-dir /hosts
tf --config examples/etcd/tf.toml --template examples/etcd/hosts.tf --input "{ EtcdHost: ${IP} }"

You can find a more complete example in "examples/docker" for templating Dockerfile and configuration files, this was primary use-case for this project. However it's pretty generic and could be used for any templating in Bash.

Extended functions and tests

Tests

Examples

echo '{{range $i, $e := .Apples}}Apple: {{$e}}{{if last $i $.Apples | not}}{{printf ",\n"}}{{end}}{{end}}' | tf -l text -i '{ Apples: [ 1, 2, 3] }'
echo '{{range $k, $e := .Oranges}}{{if map $e | not }}{{printf "%s: %v\n" $k $e}}{{end}}{{end}}' | tf -l text -i '{ Oranges: { a: 1, b: 2, c: { a: 1, b: 2 } } }'
echo '{{1 | even }} | tf -l text

Functions

Examples

echo '{{split ":" .Env.PATH | join ",\n"}}' | tf -l text
echo '{{repeat 20 "-"}} HELLO WORLD! {{"-" | repeat 20}}' | tf -l text
echo '{{keys .Env | join "\n"}}' | tf -l text
echo '{{ "UPPER" | lower}} {{ "lower" | upper }}' | tf -l text
echo '{{ "Doo Doo" | replace "Doo" "Doo is extinct" }}' | tf -l text
echo '{{ "!!! TRIM !!!" | trim "! " }}' | tf -l text
echo '{{ 2 | add 2 | sub 2 | mul 5 | div 5}}' | tf -l text

Build

git clone https://github.com/mickep76/tf.git
cd tf
./build
bin/tf --version

Install using Homebrew

brew tap mickep76/funk-gnarge
brew install mickep76/funk-gnarge/tf

Template a directory structure

Template

input='input.yaml'
for file in $(find . -type f -name '*.tf'); do
    tf -i ${input} -t ${file} -o ${file%%.tf}
done

Cleanup

for file in $(find . -type f -name '*.tf'); do
    rm -f ${file%%.tf}
done

Use in Makefile

INPUT=input.yaml

all: build

clean:
        for file in $$(find . -type f -name '*.tf'); do \
                rm -f $${file%%.tf} ; \
        done

build: clean
        for file in $$(find . -type f -name '*.tf'); do \
                tf -f ${INPUT} -t $${file} -o $${file%%.tf} ; \
        done

Issues

Currently Go text/template doesn't have a way to suppress newlines.

Roadmap

• Add test's
• LDAP support
• Add sort array asc. and desc. templ. func.
• Examples with Etcd data
• Examples with MySQL data
• Validation of data input using schema
• Config that is evaluated in sorted file order for consequtive queries using prev. values "/etc/tf.d/01-http", "/etc/tf.d/02-http" etc.