migrations: add ReplaceStringMigration migration helper, simplify containerd-config-path migration, host-containers-version migration

workspaces/api/migration/migration-helpers/Cargo.toml

@@ -9,7 +9,7 @@ publish = false
 apiserver = { path = "../../apiserver" }
 snafu = "0.6"
 toml = "0.5"
+serde_json = "1.0"
 
 [dev-dependencies]
 maplit = "1.0"
-serde_json = "1.0"

workspaces/api/migration/migration-helpers/src/common_migrations.rs

@@ -51,3 +51,68 @@ impl Migration for RemoveSettingMigration {
         Ok(input)
     }
 }
+
+// =^..^=   =^..^=   =^..^=   =^..^=   =^..^=   =^..^=   =^..^=   =^..^=   =^..^=
+
+/// We use this migration when we replace a setting's old string value with a new string value.
+pub struct ReplaceStringMigration {
+    pub setting: &'static str,
+    pub old_val: &'static str,
+    pub new_val: &'static str,
+}
+
+impl Migration for ReplaceStringMigration {
+    fn forward(&mut self, mut input: MigrationData) -> Result<MigrationData> {
+        if let Some(data) = input.data.get_mut(self.setting) {
+            match data {
+                serde_json::Value::String(data) => {
+                    if data == self.old_val {
+                        *data = self.new_val.to_owned();
+                        println!(
+                            "Changed value of '{}' from '{}' to '{}' on upgrade",
+                            self.setting, self.old_val, self.new_val
+                        );
+                    } else {
+                        println!("'{}' is not set to '{}', leaving alone", self.setting, self.old_val);
+                    }
+                }
+                _ => {
+                    println!(
+                        "'{}' is set to non-string value '{}'; ReplaceStringMigration only handles strings",
+                        self.setting, data
+                    );
+                }
+            }
+        } else {
+            println!("Found no '{}' to change on upgrade", self.setting);
+        }
+        Ok(input)
+    }
+
+    fn backward(&mut self, mut input: MigrationData) -> Result<MigrationData> {
+        if let Some(data) = input.data.get_mut(self.setting) {
+            match data {
+                serde_json::Value::String(data) => {
+                    if data == self.new_val {
+                        *data = self.old_val.to_owned();
+                        println!(
+                            "Changed value of '{}' from '{}' to '{}' on downgrade",
+                            self.setting, self.new_val, self.old_val
+                        );
+                    } else {
+                        println!("'{}' is not set to '{}', leaving alone", self.setting, self.new_val);
+                    }
+                }
+                _ => {
+                    println!(
+                        "'{}' is set to non-string value '{}'; ReplaceStringMigration only handles strings",
+                        self.setting, data
+                    );
+                }
+            }
+        } else {
+            println!("Found no '{}' to change on downgrade", self.setting);
+        }
+        Ok(input)
+    }
+}

workspaces/api/migration/migrations/v0.1/migrate-host-containers-version/src/main.rs

@@ -1,10 +1,9 @@
 #![deny(rust_2018_idioms)]
 
-use migration_helpers::{migrate, Migration, MigrationData, Result};
+use migration_helpers::{migrate, Result};
+use migration_helpers::common_migrations::ReplaceStringMigration;
 use std::process;
 
-/// We bumped the versions of the default admin container and the default control container from v0.1 to v0.2
-struct HostContainersVersionMigration;
 const DEFAULT_ADMIN_CTR_IMG_OLD: &str =
     "328549459982.dkr.ecr.us-west-2.amazonaws.com/thar-admin:v0.1";
 const DEFAULT_ADMIN_CTR_IMG_NEW: &str =
@@ -14,53 +13,18 @@ const DEFAULT_CONTROL_CTR_IMG_OLD: &str =
 const DEFAULT_CONTROL_CTR_IMG_NEW: &str =
     "328549459982.dkr.ecr.us-west-2.amazonaws.com/thar-control:v0.2";
 
-impl Migration for HostContainersVersionMigration {
-    fn forward(&mut self, mut input: MigrationData) -> Result<MigrationData> {
-        if let Some(admin_ctr_source) = input.data.get_mut("settings.host-containers.admin.source")
-        {
-            // Need to bump versions if the default admin container version source matches its older version
-            if admin_ctr_source.as_str() == Some(DEFAULT_ADMIN_CTR_IMG_OLD) {
-                *admin_ctr_source =
-                    serde_json::Value::String(DEFAULT_ADMIN_CTR_IMG_NEW.to_string());
-            }
-        }
-        if let Some(control_ctr_source) = input
-            .data
-            .get_mut("settings.host-containers.control.source")
-        {
-            // Need to bump versions if the default control container version source matches its older version
-            if control_ctr_source.as_str() == Some(DEFAULT_CONTROL_CTR_IMG_OLD) {
-                *control_ctr_source =
-                    serde_json::Value::String(DEFAULT_CONTROL_CTR_IMG_NEW.to_string());
-            }
-        }
-        Ok(input)
-    }
-
-    fn backward(&mut self, mut input: MigrationData) -> Result<MigrationData> {
-        if let Some(admin_ctr_source) = input.data.get_mut("settings.host-containers.admin.source")
-        {
-            // The default admin container v0.2 image needs OS changes adding persistent host container storage
-            if admin_ctr_source.as_str() == Some(DEFAULT_ADMIN_CTR_IMG_NEW) {
-                *admin_ctr_source =
-                    serde_json::Value::String(DEFAULT_ADMIN_CTR_IMG_OLD.to_string());
-            }
-        }
-        if let Some(control_ctr_source) = input
-            .data
-            .get_mut("settings.host-containers.control.source")
-        {
-            if control_ctr_source.as_str() == Some(DEFAULT_CONTROL_CTR_IMG_NEW) {
-                *control_ctr_source =
-                    serde_json::Value::String(DEFAULT_CONTROL_CTR_IMG_OLD.to_string());
-            }
-        }
-        Ok(input)
-    }
-}
-
+/// We bumped the versions of the default admin container and the default control container from v0.1 to v0.2
 fn run() -> Result<()> {
-    migrate(HostContainersVersionMigration)
+    migrate(ReplaceStringMigration {
+        setting: "settings.host-containers.admin.source",
+        old_val: DEFAULT_ADMIN_CTR_IMG_OLD,
+        new_val: DEFAULT_ADMIN_CTR_IMG_NEW,
+    })?;
+    migrate(ReplaceStringMigration {
+        setting: "settings.host-containers.control.source",
+        old_val: DEFAULT_CONTROL_CTR_IMG_OLD,
+        new_val: DEFAULT_CONTROL_CTR_IMG_NEW,
+    })
 }
 
 // Returning a Result from main makes it print a Debug representation of the error, but with Snafu

workspaces/api/migration/migrations/v0.2/migrate-containerd-config-path/src/main.rs

@@ -1,41 +1,24 @@
 #![deny(rust_2018_idioms)]
 
-use migration_helpers::{migrate, Migration, MigrationData, Result};
+use migration_helpers::{migrate, Result};
+use migration_helpers::common_migrations::ReplaceStringMigration;
 use std::process;
 
-/// We changed the path to our containerd configuration template so that we could support image
-/// variants with different configs.  We need to update old images to the new path, and on
-/// downgrade, new images to the old path.
-struct ContainerdConfigPath;
-
 const SETTING: &str = "configuration-files.containerd-config-toml.template-path";
 // Old version with no variant
 const DEFAULT_CTRD_CONFIG_OLD: &str = "/usr/share/templates/containerd-config-toml";
 // Any users coming from old versions would be using the aws-k8s variant because no other existed :)
 const DEFAULT_CTRD_CONFIG_NEW: &str = "/usr/share/templates/containerd-config-toml_aws-k8s";
 
-impl Migration for ContainerdConfigPath {
-    fn forward(&mut self, mut input: MigrationData) -> Result<MigrationData> {
-        if let Some(cfg_path) = input.data.get_mut(SETTING) {
-            if cfg_path.as_str() == Some(DEFAULT_CTRD_CONFIG_OLD) {
-                *cfg_path = serde_json::Value::String(DEFAULT_CTRD_CONFIG_NEW.to_string());
-            }
-        }
-        Ok(input)
-    }
-
-    fn backward(&mut self, mut input: MigrationData) -> Result<MigrationData> {
-        if let Some(cfg_path) = input.data.get_mut(SETTING) {
-            if cfg_path.as_str() == Some(DEFAULT_CTRD_CONFIG_NEW) {
-                *cfg_path = serde_json::Value::String(DEFAULT_CTRD_CONFIG_OLD.to_string());
-            }
-        }
-        Ok(input)
-    }
-}
-
+/// We changed the path to our containerd configuration template so that we could support image
+/// variants with different configs.  We need to update old images to the new path, and on
+/// downgrade, new images to the old path.
 fn run() -> Result<()> {
-    migrate(ContainerdConfigPath)
+    migrate(ReplaceStringMigration {
+        setting: SETTING,
+        old_val: DEFAULT_CTRD_CONFIG_OLD,
+        new_val: DEFAULT_CTRD_CONFIG_NEW
+    })
 }
 
 // Returning a Result from main makes it print a Debug representation of the error, but with Snafu