Bootstrap Companions in Kubernetes Environments

This commit introduces the configuration `bootstrapping.containers`
which provides a way to parse the configuration of application wide
companions because the current available configuration of companions if
quite limiting (Current backends, Docker and Kubernetes, offer way more
options than the PREvant configuration object allows). For example,
PREvant was limited to self-contained applications where each
microservice only relies on interactions via network API calls (REST,
database connections, messaging, etc.) With this commit PREvant is now
able to deploy application companions that are more powerful than the
PREvant configuration in Kubernetes backends.

If `bootstrapping.containers` is defined, PREvant will start one or more
containers on the infrastructure backend that are expected to generate
Kubernetes manifests as output on standard out (stdout) that will be
parsed by PREvant and supported are:

 - roles and role bindings
 - config maps and secrets
 - service accounts
 - persistent volume claims
 - services
 - pods, deployments, stateful sets, and jobs

Then before deploying these manifests PREvant merges all objects with
the objects generated from the HTTP request payload. Thus you can add or
overwrite configurations. For example, you can change the image used or
an environment variable. If you overwrite any configuration the
companion will be turned into an instance (as PREvant did before).

Ingresses won't be deployed if the bootstrap container outputs one of
these. Instead they will be parsed and if they use the ingress class
`nginx` they will be transformed into Traefik ingresses and middlewares
so that the microservices will be available via web interface.

This approach make #143 obsolete and fixes #123 and contributes to #146.

api/Cargo.toml

@@ -26,14 +26,15 @@ futures = { version = "0.3", features = ["compat"] }
 handlebars = "4.5"
 http-api-problem = "0.57"
 jira_query = "1.3"
-k8s-openapi = { version = "0.18", default-features = false, features = ["v1_24"] }
-kube = { version = "0.84", default-features = false, features = ["client", "derive", "rustls-tls"] }
+k8s-openapi = { version = "0.20", default-features = false, features = ["v1_24"] }
+kube = { version = "0.87", default-features = false, features = ["client", "derive", "rustls-tls"] }
 lazy_static = "1.4"
 log = "0.4"
 multimap = "0.9"
 pest = "2.6"
 pest_derive = "2.6"
-regex = "1.9"
+regex = "1.10"
+regex-syntax = "0.8"
 reqwest = { version = "0.11", features = ["json"] }
 rocket = { version = "0.5", features = ["json"] }
 schemars = "0.8"
@@ -45,9 +46,9 @@ serde_json = "1.0"
 serde_regex = "1.1"
 serde_yaml = "0.9"
 tokio = { version = "1.29", features = ["macros", "rt", "rt-multi-thread", "sync", "time"] }
-toml = "0.7"
+toml = "0.8"
 url = { version = "2.4", features = ["serde"] }
-uuid = { version = "1.3", features = ["serde", "v4"] }
+uuid = { version = "1.5", features = ["serde", "v4"] }
 yansi = "0.5"
 
 

api/src/apps/mod.rs

@@ -285,6 +285,12 @@ impl AppsService {
         let deployment_unit = if let Ok(Some(base_traefik_ingress_route)) =
             self.infrastructure.base_traefik_ingress_route().await
         {
+            trace!(
+                "The base URL for {app_name} is: {:?}",
+                base_traefik_ingress_route
+                    .to_url()
+                    .map(|url| url.to_string())
+            );
             deployment_unit_builder
                 .apply_base_traefik_ingress_route(base_traefik_ingress_route)
                 .build()
@@ -511,7 +517,7 @@ mod tests {
         let apps = AppsService::new(config, infrastructure)?;
 
         apps.create_or_update(
-            &AppName::from_str("master").unwrap(),
+            &AppName::master(),
             &AppStatusChangeId::new(),
             None,
             &vec![sc!("service-a"), sc!("service-b")],
@@ -521,7 +527,7 @@ mod tests {
         apps.create_or_update(
             &AppName::from_str("branch").unwrap(),
             &AppStatusChangeId::new(),
-            Some(AppName::from_str("master").unwrap()),
+            Some(AppName::master()),
             &vec![sc!("service-b")],
         )
         .await?;
@@ -563,7 +569,7 @@ mod tests {
         apps.create_or_update(
             &AppName::from_str("branch").unwrap(),
             &AppStatusChangeId::new(),
-            Some(AppName::from_str("master").unwrap()),
+            Some(AppName::master()),
             &vec![sc!("service-a")],
         )
         .await?;
@@ -596,7 +602,7 @@ mod tests {
         let apps = AppsService::new(config, infrastructure)?;
 
         apps.create_or_update(
-            &AppName::from_str("master").unwrap(),
+            &AppName::master(),
             &AppStatusChangeId::new(),
             None,
             &vec![sc!("mariadb")],
@@ -660,7 +666,7 @@ mod tests {
         let infrastructure = Box::new(Dummy::new());
         let apps = AppsService::new(config, infrastructure)?;
 
-        let app_name = AppName::from_str("master").unwrap();
+        let app_name = AppName::master();
 
         apps.create_or_update(
             &app_name,
@@ -857,7 +863,7 @@ Log msg 3 of service-a of app master
 
         let infrastructure = Box::new(Dummy::new());
         let apps = AppsService::new(config, infrastructure)?;
-        let app_name = AppName::from_str("master").unwrap();
+        let app_name = AppName::master();
 
         apps.create_or_update(
             &app_name,
@@ -942,7 +948,7 @@ Log msg 3 of service-a of app master
         let infrastructure = Box::new(Dummy::with_delay(std::time::Duration::from_millis(500)));
         let apps = Arc::new(AppsService::new(config, infrastructure)?);
 
-        let app_name = AppName::from_str("master").unwrap();
+        let app_name = AppName::master();
         apps.create_or_update(
             &app_name,
             &AppStatusChangeId::new(),
@@ -959,7 +965,7 @@ Log msg 3 of service-a of app master
                 .unwrap();
             rt.block_on(apps_clone.delete_app(&app_name, &AppStatusChangeId::new()))
         });
-        let app_name = AppName::from_str("master").unwrap();
+        let app_name = AppName::master();
         let handle2 = std::thread::spawn(move || {
             let rt = runtime::Builder::new_current_thread()
                 .enable_time()
@@ -1055,7 +1061,7 @@ Log msg 3 of service-a of app master
         "#;
 
         let (_temp_js_file, config) = config_with_deployment_hook(script);
-        let app_name = &AppName::from_str("master").unwrap();
+        let app_name = &AppName::master();
         let infrastructure = Box::new(Dummy::new());
         let apps = AppsService::new(config, infrastructure)?;
 
@@ -1087,7 +1093,7 @@ Log msg 3 of service-a of app master
         )));
         let apps = AppsService::new(Config::default(), infrastructure)?;
 
-        let app_name = &AppName::from_str("master").unwrap();
+        let app_name = &AppName::master();
         apps.create_or_update(
             &app_name,
             &AppStatusChangeId::new(),
@@ -1129,7 +1135,7 @@ Log msg 3 of service-a of app master
         let infrastructure = Box::new(Dummy::new());
         let apps = AppsService::new(Config::default(), infrastructure)?;
 
-        let app_name = &AppName::from_str("master").unwrap();
+        let app_name = &AppName::master();
         apps.create_or_update(
             &app_name,
             &AppStatusChangeId::new(),

api/src/apps/routes.rs

@@ -182,7 +182,7 @@ async fn change_status(
 )]
 async fn logs(
     app_name: Result<AppName, AppNameError>,
-    service_name: String,
+    service_name: &str,
     since: Option<String>,
     limit: Option<usize>,
     apps: &State<Arc<Apps>>,
@@ -205,13 +205,13 @@ async fn logs(
     let limit = limit.unwrap_or(20_000);
 
     let log_chunk = apps
-        .get_logs(&app_name, &service_name, &since, limit)
+        .get_logs(&app_name, &service_name.to_string(), &since, limit)
         .await?;
 
     Ok(LogsResponse {
         log_chunk,
         app_name,
-        service_name,
+        service_name: service_name.to_string(),
         limit,
     })
 }

api/src/config/app_selector.rs

@@ -23,16 +23,17 @@
  * THE SOFTWARE.
  * =========================LICENSE_END==================================
  */
+use crate::models::AppName;
 use regex::Regex;
 
 #[derive(Clone)]
 pub(super) struct AppSelector(Regex);
 
 impl AppSelector {
-    pub fn matches(&self, app_name: &str) -> bool {
+    pub fn matches(&self, app_name: &AppName) -> bool {
         match self.0.captures(app_name) {
             None => false,
-            Some(captures) => captures.get(0).map_or("", |m| m.as_str()) == app_name,
+            Some(captures) => captures.get(0).map_or("", |m| m.as_str()) == app_name.as_str(),
         }
     }
 }

api/src/config/companion.rs

@@ -25,11 +25,21 @@
  */
 use crate::config::AppSelector;
 use crate::models::service::ContainerType;
-use crate::models::{Environment, Image, Router, ServiceConfig};
+use crate::models::{AppName, Environment, Image, Router, ServiceConfig};
+use handlebars::Handlebars;
 use secstr::SecUtf8;
 use serde_value::Value;
 use std::collections::BTreeMap;
 use std::path::PathBuf;
+use url::Url;
+
+#[derive(Clone, Default, Deserialize)]
+pub(super) struct Companions {
+    #[serde(default)]
+    bootstrapping: Bootstrapping,
+    #[serde(flatten)]
+    companions: BTreeMap<String, Companion>,
+}
 
 #[derive(Clone, Deserialize)]
 #[serde(rename_all = "camelCase")]
@@ -78,12 +88,52 @@ pub enum DeploymentStrategy {
     RedeployNever,
 }
 
+#[derive(Clone, Default, Deserialize)]
+struct Bootstrapping {
+    containers: Vec<BootstrappingContainer>,
+}
+
+#[derive(Clone, Deserialize)]
+pub struct BootstrappingContainer {
+    image: Image,
+    #[serde(default)]
+    args: Vec<String>,
+}
+
+impl Companions {
+    pub(super) fn companion_configs<P>(
+        &self,
+        app_name: &AppName,
+        predicate: P,
+    ) -> Vec<(ServiceConfig, DeploymentStrategy, StorageStrategy)>
+    where
+        P: Fn(&Companion) -> bool,
+    {
+        self.companions
+            .iter()
+            .filter(|(_, companion)| companion.matches_app_name(app_name))
+            .filter(|(_, companion)| predicate(companion))
+            .map(|(_, companion)| {
+                (
+                    ServiceConfig::from(companion.clone()),
+                    companion.deployment_strategy().clone(),
+                    companion.storage_strategy().clone(),
+                )
+            })
+            .collect()
+    }
+
+    pub(super) fn companion_bootstrapping_containers(&self) -> &Vec<BootstrappingContainer> {
+        &self.bootstrapping.containers
+    }
+}
+
 impl Companion {
     pub fn companion_type(&self) -> &CompanionType {
         &self.companion_type
     }
 
-    pub fn matches_app_name(&self, app_name: &str) -> bool {
+    pub fn matches_app_name(&self, app_name: &AppName) -> bool {
         self.app_selector.matches(app_name)
     }
 
@@ -149,6 +199,42 @@ impl Default for StorageStrategy {
     }
 }
 
+impl BootstrappingContainer {
+    pub fn image(&self) -> &Image {
+        &self.image
+    }
+
+    pub fn templated_args(&self, app_name: &AppName, base_url: &Option<Url>) -> Vec<String> {
+        let handlebars = Handlebars::new();
+
+        #[derive(Serialize)]
+        #[serde(rename_all = "camelCase")]
+        struct AppData<'a> {
+            name: &'a str,
+            #[serde(skip_serializing_if = "Option::is_none")]
+            base_url: &'a Option<Url>,
+        }
+        // TODO: apply same pattern as for companions. {{application.name}}, {{service.…}}…
+        #[derive(Serialize)]
+        struct Data<'a> {
+            application: AppData<'a>,
+        }
+
+        let data = Data {
+            application: AppData {
+                name: &app_name,
+                base_url,
+            },
+        };
+
+        self.args
+            .iter()
+            // TODO: handle result
+            .map(|arg| handlebars.render_template(&arg, &data).unwrap())
+            .collect()
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -160,6 +246,12 @@ mod tests {
         };
     }
 
+    macro_rules! companions_from_str {
+        ( $config_str:expr ) => {
+            toml::de::from_str::<Companions>($config_str).unwrap()
+        };
+    }
+
     #[test]
     fn should_parse_companion_with_required_fields() {
         let companion = companion_from_str!(
@@ -181,4 +273,66 @@ mod tests {
             DeploymentStrategy::RedeployAlways
         );
     }
+
+    #[test]
+    fn should_parse_companion_bootstrap_containers() {
+        let companions = companions_from_str!(
+            r#"
+            [[bootstrapping.containers]]
+            image = "busybox"
+            "#
+        );
+
+        let container = &companions.bootstrapping.containers[0];
+
+        assert_eq!(container.image, Image::from_str("busybox").unwrap());
+        assert_eq!(
+            container.templated_args(&AppName::master(), &None),
+            Vec::<String>::new()
+        );
+    }
+
+    #[test]
+    fn should_parse_companion_bootstrap_containers_and_template_args() {
+        let companions = companions_from_str!(
+            r#"
+            [[bootstrapping.containers]]
+            image = "busybox"
+            args = [ "echo", "Hello {{application.name}}" ]
+            "#
+        );
+
+        let container = &companions.bootstrapping.containers[0];
+
+        assert_eq!(container.image, Image::from_str("busybox").unwrap());
+        assert_eq!(
+            container.templated_args(&AppName::master(), &None),
+            vec![String::from("echo"), String::from("Hello master")]
+        );
+    }
+
+    #[test]
+    fn should_parse_companion_bootstrap_containers_and_template_url_args() {
+        let companions = companions_from_str!(
+            r#"
+            [[bootstrapping.containers]]
+            image = "busybox"
+            args = [ "echo", "Hello {{application.baseUrl}}" ]
+            "#
+        );
+
+        let container = &companions.bootstrapping.containers[0];
+
+        assert_eq!(container.image, Image::from_str("busybox").unwrap());
+        assert_eq!(
+            container.templated_args(
+                &AppName::master(),
+                &Some(Url::parse("http://example.com").unwrap())
+            ),
+            vec![
+                String::from("echo"),
+                String::from("Hello http://example.com/")
+            ]
+        );
+    }
 }