Shorten the default retention, dramatically.

The original retention values were loosely based on Slack's retention, for lack of a more specific motivator. Today's election results have changed my views; the service now defaults to retention more in line with the needs of communities for which deep message history may be a risk:

* Unused channels expire after 7 days.
* Used channels expire when their last message expires (as before).
* Deleted channels are purged after 6 hours (which is in line with the purge behaviour of messages).
* Messages expire after 15 days.
* Deleted messages are purged after 6 hours (as before).

No changes have been made to token expiry.

3 files changed, 8 insertions, 7 deletions

diff --git a/src/channel/app.rs b/src/channel/app.rs
index 21784e9..1e341e3 100644
--- a/src/channel/app.rs
+++ b/src/channel/app.rs
@@ -97,8 +97,9 @@ impl<'a> Channels<'a> {
     }
 
     pub async fn expire(&self, relative_to: &DateTime) -> Result<(), ExpireError> {
-        // Somewhat arbitrarily, expire after 90 days.
-        let expire_at = relative_to.to_owned() - TimeDelta::days(90);
+        // Somewhat arbitrarily, expire after 7 days. Active channels will not be
+        // expired until their messages expire.
+        let expire_at = relative_to.to_owned() - TimeDelta::days(7);
 
         let mut tx = self.db.begin().await?;
         let expired = tx.channels().expired(&expire_at).await?;
@@ -128,8 +129,8 @@ impl<'a> Channels<'a> {
     }
 
     pub async fn purge(&self, relative_to: &DateTime) -> Result<(), sqlx::Error> {
-        // Somewhat arbitrarily, purge after 7 days.
-        let purge_at = relative_to.to_owned() - TimeDelta::days(7);
+        // Somewhat arbitrarily, purge after 6 hours.
+        let purge_at = relative_to.to_owned() - TimeDelta::hours(6);
 
         let mut tx = self.db.begin().await?;
         tx.channels().purge(&purge_at).await?;
diff --git a/src/message/app.rs b/src/message/app.rs
index 137a27d..7bf68d1 100644
--- a/src/message/app.rs
+++ b/src/message/app.rs
@@ -80,8 +80,8 @@ impl<'a> Messages<'a> {
     }
 
     pub async fn expire(&self, relative_to: &DateTime) -> Result<(), sqlx::Error> {
-        // Somewhat arbitrarily, expire after 90 days.
-        let expire_at = relative_to.to_owned() - TimeDelta::days(90);
+        // Somewhat arbitrarily, expire after 15 days.
+        let expire_at = relative_to.to_owned() - TimeDelta::days(15);
 
         let mut tx = self.db.begin().await?;
 
diff --git a/src/test/fixtures/mod.rs b/src/test/fixtures/mod.rs
index 470b31a..21e4483 100644
--- a/src/test/fixtures/mod.rs
+++ b/src/test/fixtures/mod.rs
@@ -24,7 +24,7 @@ pub fn now() -> RequestedAt {
 }
 
 pub fn old() -> RequestedAt {
-    let timestamp = Utc::now() - TimeDelta::days(95);
+    let timestamp = Utc::now() - TimeDelta::days(20);
     timestamp.into()
 }