cli: introduce the export_graphql_schema command

Split the command line into subcommands `run` and
`export_graphql_schema`.

.github/workflows/rust.yml

@@ -21,6 +21,11 @@ jobs:
         run: cargo build --verbose --workspace
       - name: Run tests
         run: cargo test --verbose --workspace
+      - name: Generate GraphQL schema
+        run: cargo run -- export_graphql_schema -o generated_schema.graphql
+      - name: Check schema
+        run: diff schema.graphql generated_schema.graphql
+
 
   clippy:
     name: cargo clippy

schema.graphql

@@ -0,0 +1,38 @@
+input EqualityConstraint {
+  field: String!
+  value: String!
+}
+
+type Group {
+  id: String!
+  "The groups to which this user belongs."
+  users: [User!]!
+}
+
+"""
+  A filter for requests, specifying a boolean expression based on field constraints. Only one of
+  the fields can be set at a time.
+"""
+input RequestFilter {
+  any: [RequestFilter!]
+  all: [RequestFilter!]
+  not: RequestFilter
+  eq: EqualityConstraint
+}
+
+type Query {
+  apiVersion: String!
+  user(userId: String!): User!
+  users(filters: RequestFilter): [User!]!
+}
+
+type User {
+  id: String!
+  email: String!
+  "The groups to which this user belongs."
+  groups: [Group!]!
+}
+
+schema {
+  query: Query
+}

src/infra/cli.rs

@@ -4,6 +4,23 @@ use clap::Clap;
 #[derive(Debug, Clap, Clone)]
 #[clap(version = "0.1", author = "The LLDAP team")]
 pub struct CLIOpts {
+    /// Export
+    #[clap(subcommand)]
+    pub command: Command,
+}
+
+#[derive(Debug, Clap, Clone)]
+pub enum Command {
+    /// Export the GraphQL schema to *.graphql.
+    #[clap(name = "export_graphql_schema")]
+    ExportGraphQLSchema(ExportGraphQLSchemaOpts),
+    /// Run the LDAP and GraphQL server.
+    #[clap(name = "run")]
+    Run(RunOpts),
+}
+
+#[derive(Debug, Clap, Clone)]
+pub struct RunOpts {
     /// Change config file name
     #[clap(short, long, default_value = "lldap_config.toml")]
     pub config_file: String,
@@ -21,6 +38,13 @@ pub struct CLIOpts {
     pub verbose: bool,
 }
 
+#[derive(Debug, Clap, Clone)]
+pub struct ExportGraphQLSchemaOpts {
+    /// Output to a file. If not specified, the config is printed to the standard output.
+    #[clap(short, long)]
+    pub output_file: Option<String>,
+}
+
 pub fn init() -> CLIOpts {
     CLIOpts::parse()
 }

src/infra/configuration.rs

@@ -6,7 +6,7 @@ use figment::{
 use lldap_model::opaque::{server::ServerSetup, KeyPair};
 use serde::{Deserialize, Serialize};
 
-use crate::infra::cli::CLIOpts;
+use crate::infra::cli::RunOpts;
 
 #[derive(Clone, Debug, Deserialize, Serialize, derive_builder::Builder)]
 #[builder(
@@ -55,7 +55,7 @@ impl Configuration {
         self.get_server_setup().keypair()
     }
 
-    fn merge_with_cli(mut self: Configuration, cli_opts: CLIOpts) -> Configuration {
+    fn merge_with_cli(mut self: Configuration, cli_opts: RunOpts) -> Configuration {
         if cli_opts.verbose {
             self.verbose = true;
         }
@@ -110,7 +110,7 @@ fn get_server_setup(file_path: &str) -> Result<ServerSetup> {
     }
 }
 
-pub fn init(cli_opts: CLIOpts) -> Result<Configuration> {
+pub fn init(cli_opts: RunOpts) -> Result<Configuration> {
     let config_file = cli_opts.config_file.clone();
 
     let config: Configuration = Figment::from(Serialized::defaults(Configuration::default()))

src/infra/graphql/api.rs

@@ -2,6 +2,7 @@ use crate::{
     domain::handler::BackendHandler,
     infra::{
         auth_service::{check_if_token_is_valid, ValidationResults},
+        cli::ExportGraphQLSchemaOpts,
         tcp_server::AppState,
     },
 };
@@ -34,6 +35,26 @@ fn schema<Handler: BackendHandler + Sync>() -> Schema<Handler> {
     )
 }
 
+pub fn export_schema(opts: ExportGraphQLSchemaOpts) -> anyhow::Result<()> {
+    use crate::domain::sql_backend_handler::SqlBackendHandler;
+    use anyhow::Context;
+    let output = schema::<SqlBackendHandler>().as_schema_language();
+    match opts.output_file {
+        None => println!("{}", output),
+        Some(path) => {
+            use std::fs::File;
+            use std::io::prelude::*;
+            use std::path::Path;
+            let path = Path::new(&path);
+            let mut file =
+                File::create(&path).context(format!("unable to open '{}'", path.display()))?;
+            file.write_all(output.as_bytes())
+                .context(format!("unable to write in '{}'", path.display()))?;
+        }
+    }
+    Ok(())
+}
+
 async fn graphiql_route() -> Result<HttpResponse, Error> {
     graphiql_handler("/api/graphql", None).await
 }

src/main.rs

@@ -6,7 +6,7 @@ use crate::{
         handler::BackendHandler, sql_backend_handler::SqlBackendHandler,
         sql_opaque_handler::register_password, sql_tables::PoolOptions,
     },
-    infra::{configuration::Configuration, db_cleaner::Scheduler},
+    infra::{cli::*, configuration::Configuration, db_cleaner::Scheduler},
 };
 use actix::Actor;
 use anyhow::{anyhow, Result};
@@ -65,14 +65,13 @@ async fn run_server(config: Configuration) -> Result<()> {
     Ok(())
 }
 
-fn main() -> Result<()> {
-    let cli_opts = infra::cli::init();
-    let config = infra::configuration::init(cli_opts.clone())?;
+fn run_server_command(opts: RunOpts) -> Result<()> {
+    let config = infra::configuration::init(opts.clone())?;
     infra::logging::init(config.clone())?;
 
     info!("Starting LLDAP....");
 
-    debug!("CLI: {:#?}", cli_opts);
+    debug!("CLI: {:#?}", opts);
     debug!("Configuration: {:#?}", config);
 
     actix::run(
@@ -82,3 +81,11 @@ fn main() -> Result<()> {
     info!("End.");
     Ok(())
 }
+
+fn main() -> Result<()> {
+    let cli_opts = infra::cli::init();
+    match cli_opts.command {
+        Command::ExportGraphQLSchema(opts) => infra::graphql::api::export_schema(opts),
+        Command::Run(opts) => run_server_command(opts),
+    }
+}