Add floki render to print out the rendered configuration template.

Signed-off-by: Max Dymond <max.dymond@microsoft.com>

Author: Max Dymond

CHANGELOG.md

@@ -20,6 +20,7 @@ Status: Available for use
   can use `jsonload(file="<filepath>")` in order to load values.
 - Add `tomlload` function to tera templating engine so that floki templates
   can use `tomlload(file="<filepath>")` in order to load values.
+- Add `floki render` to print out the rendered configuration template.
 
 ### Fixed
 

src/cli.rs

@@ -20,6 +20,11 @@ pub(crate) enum Subcommand {
         #[structopt(name = "SHELL", parse(try_from_str))]
         shell: structopt::clap::Shell,
     },
+
+    /// Render the configuration file to stdout, performing any templating
+    /// operations.
+    #[structopt(name = "render")]
+    Render {},
 }
 
 /// Main CLI interface

src/config.rs

@@ -156,10 +156,7 @@ pub fn render_template(template: &str, source_filename: &Path) -> Result<String,
 }
 
 impl FlokiConfig {
-    pub fn from_file(file: &Path) -> Result<Self, Error> {
-        debug!("Reading configuration file: {:?}", file);
-
-        // Read the content from the path
+    pub fn render(file: &Path) -> Result<String, Error> {
         let content = std::fs::read_to_string(file).map_err(|e| {
             errors::FlokiError::ProblemOpeningConfigYaml {
                 name: file.display().to_string(),
@@ -168,7 +165,14 @@ impl FlokiConfig {
         })?;
 
         // Render the template first before parsing it.
-        let output = render_template(&content, file)?;
+        render_template(&content, file)
+    }
+
+    pub fn from_file(file: &Path) -> Result<Self, Error> {
+        debug!("Reading configuration file: {:?}", file);
+
+        // Render the output from the configuration file before parsing.
+        let output = Self::render(file)?;
 
         // Parse the rendered floki file from the string.
         let mut config: FlokiConfig = serde_yaml::from_str(&output).map_err(|e| {

src/main.rs

@@ -63,6 +63,13 @@ fn run_floki_from_args(args: &Cli) -> Result<(), Error> {
             Ok(())
         }
 
+        Some(Subcommand::Render {}) => {
+            let env = Environment::gather(&args.config_file)?;
+            let contents = FlokiConfig::render(&env.config_file)?;
+            println!("{contents}");
+            Ok(())
+        }
+
         // Launch an interactive floki shell (the default)
         None => {
             let env = Environment::gather(&args.config_file)?;