feat(users/Profpatsch/netencode): add env-splice-record r/2543

It’s the inverse of record-splice-env! It sucks up the environment and
prints it as a netencode dict! Only the utf-8 clean parts at least.

Change-Id: I96c19fc5ea3a67a23e238f15f4d0fa783081859c
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2527
Tested-by: BuildkiteCI
Reviewed-by: Profpatsch <mail@profpatsch.de>

2 files changed, 37 insertions, 8 deletions

diff --git a/users/Profpatsch/netencode/default.nix b/users/Profpatsch/netencode/default.nix
index b913c3e39d79..3088ee66bfe4 100644
--- a/users/Profpatsch/netencode/default.nix
+++ b/users/Profpatsch/netencode/default.nix
@@ -86,12 +86,39 @@ let
     }
   '';
 
+  env-splice-record = imports.writers.rustSimple {
+    name = "env-splice-record";
+    dependencies = [
+      netencode-rs
+      depot.users.Profpatsch.execline.exec-helpers
+    ];
+  } ''
+    extern crate netencode;
+    extern crate exec_helpers;
+    use netencode::{T};
+    use std::os::unix::ffi::OsStringExt;
+
+    fn main() {
+        exec_helpers::no_args("env-splice-record");
+        let mut res = std::collections::HashMap::new();
+        for (key, val) in std::env::vars_os() {
+          match (String::from_utf8(key.into_vec()), String::from_utf8(val.into_vec())) {
+            (Ok(k), Ok(v)) => { let _ = res.insert(k, T::Text(v)); },
+            // same as in record-splice-env, we ignore non-utf8 variables
+            (_, _) => {},
+          }
+        }
+        netencode::encode(&mut std::io::stdout(), &T::Record(res).to_u()).unwrap()
+    }
+  '';
+
 in depot.nix.utils.drvTargets {
   inherit
-   netencode-rs
-   netencode-mustache
-   record-get
-   record-splice-env
-   gen
-   ;
+    netencode-rs
+    netencode-mustache
+    record-get
+    record-splice-env
+    env-splice-record
+    gen
+    ;
 }
diff --git a/users/Profpatsch/netencode/netencode.rs b/users/Profpatsch/netencode/netencode.rs
index 249cc33ed1c0..ab10af307c6f 100644
--- a/users/Profpatsch/netencode/netencode.rs
+++ b/users/Profpatsch/netencode/netencode.rs
@@ -26,6 +26,7 @@ pub enum T {
     Binary(Vec<u8>),
     // Tags
     // TODO: make into &str
+    // TODO: rename to Tag
     Sum(Tag<String, T>),
     // TODO: make into &str
     Record(HashMap<String, T>),
@@ -81,9 +82,10 @@ pub enum U<'a> {
     // Text
     Text(&'a str),
     Binary(&'a [u8]),
-    // Tags
     // TODO: the U-recursion we do here means we can’t be breadth-lazy anymore
     // like we originally planned; maybe we want to go `U<'a>` → `&'a [u8]` again?
+    // Tags
+    // TODO: rename to Tag
     Sum(Tag<&'a str, U<'a>>),
     Record(HashMap<&'a str, U<'a>>),
     List(Vec<U<'a>>),
@@ -195,7 +197,7 @@ pub fn u_from_stdin_or_die_user_error<'a>(prog_name: &'_ str, stdin_buf: &'a mut
     let u = match parse::u_u(stdin_buf) {
         Ok((rest, u)) => match rest {
             b"" => u,
-            _ => exec_helpers::die_user_error(prog_name, format!("stdin contained some soup after netencode value: {:?}", rest))
+            _ => exec_helpers::die_user_error(prog_name, format!("stdin contained some soup after netencode value: {:?}", String::from_utf8_lossy(rest)))
         },
         Err(err) => exec_helpers::die_user_error(prog_name, format!("unable to parse netencode from stdin: {:?}", err))
     };