From 90180e31ef075509dc2ec074854801dbc130a33a Mon Sep 17 00:00:00 2001
From: Luc Perkins <lucperkins@gmail.com>
Date: Thu, 16 May 2024 13:53:46 -0300
Subject: [PATCH] Add logic for determining environment

---
 flake.nix                    |  2 +-
 magic-nix-cache/src/env.rs   | 36 ++++++++++++++++++++++++++++++++++++
 magic-nix-cache/src/error.rs |  3 +++
 magic-nix-cache/src/main.rs  |  5 +++++
 4 files changed, 45 insertions(+), 1 deletion(-)
 create mode 100644 magic-nix-cache/src/env.rs

diff --git a/flake.nix b/flake.nix
index d15722f..697c2a7 100644
--- a/flake.nix
+++ b/flake.nix
@@ -55,7 +55,7 @@
             cargo-bloat
             cargo-edit
             cargo-udeps
-            cargo-watch
+            bacon
 
             age
           ];
diff --git a/magic-nix-cache/src/env.rs b/magic-nix-cache/src/env.rs
new file mode 100644
index 0000000..2af3313
--- /dev/null
+++ b/magic-nix-cache/src/env.rs
@@ -0,0 +1,36 @@
+use crate::error::Error;
+use std::env;
+
+pub enum Environment {
+    GitHubActions,
+    GitLabCI,
+    Other,
+}
+
+impl ToString for Environment {
+    fn to_string(&self) -> String {
+        use Environment::*;
+
+        String::from(match self {
+            GitHubActions => "GitHub Actions",
+            GitLabCI => "GitLab CI",
+            _ => "unspecified",
+        })
+    }
+}
+
+pub fn determine_environment() -> Environment {
+    if env_var_is_true("GITHUB_ACTIONS") {
+        Environment::GitHubActions
+    }
+
+    if env_var_is_true("CI") && env_var_is_true("GITLAB_CI") {
+        Environment::GitLabCI
+    }
+
+    Environment::Other
+}
+
+fn env_var_is_true(e: &str) -> bool {
+    env::var(e).unwrap_or(String::from("")) == String::from("true")
+}
diff --git a/magic-nix-cache/src/error.rs b/magic-nix-cache/src/error.rs
index ec1b8d3..ae479e1 100644
--- a/magic-nix-cache/src/error.rs
+++ b/magic-nix-cache/src/error.rs
@@ -19,6 +19,9 @@ pub enum Error {
     #[error("Bad Request")]
     BadRequest,
 
+    #[error("Current environment couldn't be determinate")]
+    UnknownEnv,
+
     #[error("I/O error: {0}")]
     Io(#[from] std::io::Error),
 
diff --git a/magic-nix-cache/src/main.rs b/magic-nix-cache/src/main.rs
index 4dabf22..037cb68 100644
--- a/magic-nix-cache/src/main.rs
+++ b/magic-nix-cache/src/main.rs
@@ -14,6 +14,7 @@
 
 mod api;
 mod binary_cache;
+mod env;
 mod error;
 mod flakehub;
 mod gha;
@@ -38,6 +39,8 @@ use tracing_subscriber::filter::EnvFilter;
 
 use gha_cache::Credentials;
 
+use crate::env::determine_environment;
+
 type State = Arc<StateInner>;
 
 /// GitHub Actions-powered Nix binary cache
@@ -141,6 +144,8 @@ async fn main_cli() -> Result<()> {
 
     let args = Args::parse();
 
+    let _environment = determine_environment();
+
     let metrics = Arc::new(telemetry::TelemetryReport::new());
 
     if let Some(parent) = Path::new(&args.nix_conf).parent() {