Add logic for determining environment

flake.nix

@@ -55,7 +55,7 @@
             cargo-bloat
             cargo-edit
             cargo-udeps
-            cargo-watch
+            bacon
 
             age
           ];

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")
+}

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),
 

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() {