Allow administrators to rotate VAPID keys immediately if needed.

In spite of my design preference away from CLI tools, this is a CLI tool: `pilcrow --database-url <URL> rotate-vapid-key`. This is something we can implement here and now, which does not require us to confront the long-avoided issue of how to handle the idea that some users are allowed to make server-operational changes and some aren't, by delegating the problem back to the OS.

The implementation is a little half-baked to make it easier to rip out later. I would ordinarily prefer to push both `serve` (the default verb, not actually named in this change) and `rotate-vapid-key` into their own, separate CLI submodules, with their own argument structs, but that change is much more intrusive and would make this effectively permanent. This can be yanked out in a few minutes by deleting a few lines of `cli.rs` and inlining the `serve` function.

Nonetheless, nothing is as permanent as a temporary solution, so I've written at least some bare-minimum operations documentation on how to use this and what it does.

1 files changed, 16 insertions, 1 deletions

diff --git a/src/vapid/app.rs b/src/vapid/app.rs
index 8886c9f..ddb1f4d 100644
--- a/src/vapid/app.rs
+++ b/src/vapid/app.rs
@@ -1,4 +1,4 @@
-use chrono::TimeDelta;
+use chrono::{TimeDelta, Utc};
 use sqlx::SqlitePool;
 
 use super::{History, repo, repo::Provider as _};
@@ -18,6 +18,21 @@ impl<'a> Vapid<'a> {
         Self { db, events }
     }
 
+    pub async fn rotate_key(&self, rotate_at: &DateTime) -> Result<(), sqlx::Error> {
+        let mut tx = self.db.begin().await?;
+        // This is called from a separate CLI utility (see `cli.rs`), and we _can't_ deliver events
+        // to active clients from another process, so don't do anything that would require us to
+        // send events, like generating a new key.
+        //
+        // Instead, the server's next `refresh_key` call will generate a key and notify clients
+        // of the change. All we have to do is remove the existing key, so that the server can know
+        // to do so.
+        tx.vapid().clear().await?;
+        tx.commit().await?;
+
+        Ok(())
+    }
+
     pub async fn refresh_key(&self, ensure_at: &DateTime) -> Result<(), Error> {
         let mut tx = self.db.begin().await?;
         let key = tx.vapid().current().await.optional()?;