migrations: 'container-registry.mirrors' model type migration

Release.toml

@@ -74,3 +74,6 @@ version = "1.3.0"
     "migrate_v1.3.0_hostname-affects-etc-hosts.lz4",
     "migrate_v1.3.0_control-container-v0-5-2.lz4",
 ]
+"(1.3.0, 1.4.0)" = [
+    "migrate_v1.4.0_registry-mirror-representation.lz4",
+]

sources/Cargo.toml

@@ -28,6 +28,7 @@ members = [
     "api/migration/migrations/v1.3.0/etc-hosts-service",
     "api/migration/migrations/v1.3.0/hostname-affects-etc-hosts",
     "api/migration/migrations/v1.3.0/control-container-v0-5-2",
+    "api/migration/migrations/v1.4.0/registry-mirror-representation",
 
     "bottlerocket-release",
 

sources/api/migration/migrations/v1.4.0/registry-mirror-representation/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "registry-mirror-representation"
+version = "0.1.0"
+authors = ["Erikson Tung <etung@amazon.com>"]
+license = "Apache-2.0 OR MIT"
+edition = "2018"
+publish = false
+# Don't rebuild crate just because of changes to README.
+exclude = ["README.md"]
+
+[dependencies]
+migration-helpers = { path = "../../../migration-helpers", version = "0.1.0"}
+serde_json = "1.0"

sources/api/migration/migrations/v1.4.0/registry-mirror-representation/src/main.rs

@@ -0,0 +1,133 @@
+#![deny(rust_2018_idioms)]
+
+use migration_helpers::{migrate, Migration, MigrationData, Result};
+use serde_json::{Map, Value};
+use std::collections::HashMap;
+use std::process;
+
+const MIRRORS_SETTING_NAME: &'static str = "settings.container-registry.mirrors";
+const DATASTORE_KEY_SEPARATOR: char = '.';
+
+/// This migration changes the model type of `settings.container-registry.mirrors` from `HashMap<SingleLineString, Vec<Url>>`
+/// to `Vec<RegistryMirrors>` on upgrade and vice-versa on downgrades.
+pub struct ChangeRegistryMirrorsType;
+
+// Snapshot of the `datastore::Key::valid_character` method in Bottlerocket version 1.3.0
+//
+// Determines whether a character is acceptable within a segment of a key name.  This is
+// separate from quoting; if a character isn't valid, it isn't valid quoted, either.
+fn valid_character(c: char) -> bool {
+    match c {
+        'a'..='z' | 'A'..='Z' | '0'..='9' | '_' | '-' | '/' => true,
+        _ => false,
+    }
+}
+
+impl Migration for ChangeRegistryMirrorsType {
+    /// Newer versions store `settings.container-registry.mirrors` as `Vec<RegistryMirrors>`.
+    /// Need to convert from `HashMap<SingleLineString, Vec<Url>>`.
+    fn forward(&mut self, mut input: MigrationData) -> Result<MigrationData> {
+        let mirrors: HashMap<_, _> = input
+            .data
+            .iter()
+            .filter(|&(k, _)| k.starts_with(format!("{}.", MIRRORS_SETTING_NAME).as_str()))
+            .map(|(k, v)| (k.to_owned(), v.to_owned()))
+            .collect();
+        let mut new_mirrors = Vec::new();
+        for (setting, endpoint) in mirrors {
+            // Get the registry name from the settings name. Trim any quotes the settings name might have.
+            let registry = setting
+                .strip_prefix(&format!("{}.", MIRRORS_SETTING_NAME))
+                .unwrap_or_default()
+                .trim_matches('"');
+            let mut registry_mirrors = Map::new();
+            registry_mirrors.insert("registry".to_string(), Value::String(registry.to_string()));
+            registry_mirrors.insert("endpoint".to_string(), endpoint.to_owned());
+            new_mirrors.push(Value::Object(registry_mirrors));
+            if let Some(data) = input.data.remove(&setting) {
+                println!("Removed setting '{}', which was set to '{}'", setting, data);
+            }
+        }
+        let data = Value::Array(new_mirrors);
+        println!(
+            "Creating new setting '{}', which is set to '{}'",
+            MIRRORS_SETTING_NAME, &data
+        );
+        input.data.insert(MIRRORS_SETTING_NAME.to_string(), data);
+        Ok(input)
+    }
+
+    /// Older versions store `settings.container-registry.mirrors` as `HashMap<SingleLineString, Vec<Url>>`.
+    /// Need to convert from `Vec<RegistryMirrors>`.
+    fn backward(&mut self, mut input: MigrationData) -> Result<MigrationData> {
+        if let Some(data) = input.data.get_mut(MIRRORS_SETTING_NAME).cloned() {
+            match data {
+                Value::Array(arr) => {
+                    if let Some(data) = input.data.remove(MIRRORS_SETTING_NAME) {
+                        println!(
+                            "Removed setting '{}', which was set to '{}'",
+                            MIRRORS_SETTING_NAME, data
+                        );
+                    }
+                    for obj in arr {
+                        if let Some(obj) = obj.as_object() {
+                            if let (Some(registry), Some(endpoint)) = (
+                                obj.get("registry").and_then(|s| s.as_str()),
+                                obj.get("endpoint"),
+                            ) {
+                                // Ensure the registry contains valid datastore key characters.
+                                // If we encounter any invalid key characters, we skip writing out
+                                // the setting key to prevent breakage of the datastore.
+                                if registry
+                                    .chars()
+                                    .all(|c| valid_character(c) || c == DATASTORE_KEY_SEPARATOR)
+                                {
+                                    let setting_name =
+                                        format!(r#"{}."{}""#, MIRRORS_SETTING_NAME, registry);
+                                    println!(
+                                        "Creating new setting '{}', which is set to '{}'",
+                                        setting_name, &endpoint
+                                    );
+                                    input.data.insert(setting_name, endpoint.to_owned());
+                                } else {
+                                    eprintln!(
+                                        "Container registry '{}' contains invalid datastore key character(s). Skipping to prevent datastore breakage...",
+                                        registry
+                                    );
+                                }
+                            }
+                        } else {
+                            println!(
+                                "'{}' contains non-JSON Object value: '{}'.",
+                                MIRRORS_SETTING_NAME, obj
+                            );
+                        }
+                    }
+                }
+                _ => {
+                    println!(
+                        "'{}' is not a JSON Array value: '{}'.",
+                        MIRRORS_SETTING_NAME, data
+                    );
+                }
+            }
+        } else {
+            println!("Didn't find setting '{}'", MIRRORS_SETTING_NAME);
+        }
+        Ok(input)
+    }
+}
+
+fn run() -> Result<()> {
+    migrate(ChangeRegistryMirrorsType)
+}
+
+// Returning a Result from main makes it print a Debug representation of the error, but with Snafu
+// we have nice Display representations of the error, so we wrap "main" (run) and print any error.
+// https://github.com/shepmaster/snafu/issues/110
+fn main() {
+    if let Err(e) = run() {
+        eprintln!("{}", e);
+        process::exit(1);
+    }
+}