feat: Add Environment Variable module (#409)

2 files changed, 45 insertions, 0 deletions

diff --git a/src/modules/env_var.rs b/src/modules/env_var.rs
new file mode 100644
index 000000000..bb46456a1
--- /dev/null
+++ b/src/modules/env_var.rs
@@ -0,0 +1,43 @@
+use ansi_term::Color;
+use std::env;
+
+use super::{Context, Module};
+
+/// Creates a module with the value of the chosen environment variable
+///
+/// Will display the environment variable's value if all of the following criteria are met:
+///     - env_var.disabled is absent or false
+///     - env_var.variable is defined
+///     - a variable named as the value of env_var.variable is defined
+pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
+    let mut module = context.new_module("env_var");
+    let module_style = module
+        .config_value_style("style")
+        .unwrap_or_else(|| Color::Black.bold().dimmed());
+
+    let env_name = module.config_value_str("variable")?;
+
+    let default_value = module.config_value_str("default");
+
+    let env_value = get_env_value(env_name, default_value)?;
+
+    let prefix = module.config_value_str("prefix").unwrap_or("").to_owned();
+    let suffix = module.config_value_str("suffix").unwrap_or("").to_owned();
+
+    module.set_style(module_style);
+    module.get_prefix().set_value("with ");
+    module.new_segment_if_config_exists("symbol");
+    module.new_segment("env_var", &format!("{}{}{}", prefix, env_value, suffix));
+
+    Some(module)
+}
+
+fn get_env_value(name: &str, default: Option<&str>) -> Option<String> {
+    match env::var_os(name) {
+        Some(os_value) => match os_value.into_string() {
+            Ok(value) => Some(value),
+            Err(_error) => None,
+        },
+        None => default.map(|value| value.to_owned()),
+    }
+}
diff --git a/src/modules/mod.rs b/src/modules/mod.rs
index c1618252d..82d3614a7 100644
--- a/src/modules/mod.rs
+++ b/src/modules/mod.rs
@@ -3,6 +3,7 @@ mod aws;
 mod character;
 mod cmd_duration;
 mod directory;
+mod env_var;
 mod git_branch;
 mod git_state;
 mod git_status;
@@ -30,6 +31,7 @@ pub fn handle<'a>(module: &str, context: &'a Context) -> Option<Module<'a>> {
     match module {
         "aws" => aws::module(context),
         "directory" => directory::module(context),
+        "env_var" => env_var::module(context),
         "character" => character::module(context),
         "nodejs" => nodejs::module(context),
         "rust" => rust::module(context),