From dc660d21c824baf8cce9e36944e24d1ff2320c41 Mon Sep 17 00:00:00 2001
From: bouzuya <m@bouzuya.net>
Date: Mon, 22 Aug 2022 22:30:17 +0900
Subject: [PATCH] twiq: Add firestore_rest::begin_transaction

---
 twiq/crates/db/src/event_store.rs    |  3 +-
 twiq/crates/db/src/firestore_rest.rs | 73 ++++++++++++++++++++++++++++
 twiq/crates/db/src/lib.rs            | 31 ++++++++++--
 3 files changed, 102 insertions(+), 5 deletions(-)

diff --git a/twiq/crates/db/src/event_store.rs b/twiq/crates/db/src/event_store.rs
index 993a8e83..c51cad3d 100644
--- a/twiq/crates/db/src/event_store.rs
+++ b/twiq/crates/db/src/event_store.rs
@@ -1,12 +1,11 @@
 use std::{collections::HashMap, env, str::FromStr};
 
 use reqwest::Response;
-use serde::__private::doc;
 
 use crate::{
     event::Event,
     event_stream_id::EventStreamId,
-    event_stream_seq::{self, EventStreamSeq},
+    event_stream_seq::EventStreamSeq,
     firestore_rest::{self, Document, Timestamp, Value},
 };
 
diff --git a/twiq/crates/db/src/firestore_rest.rs b/twiq/crates/db/src/firestore_rest.rs
index 5d9f9f66..253f2c68 100644
--- a/twiq/crates/db/src/firestore_rest.rs
+++ b/twiq/crates/db/src/firestore_rest.rs
@@ -147,6 +147,50 @@ pub struct Document {
     pub update_time: Timestamp,
 }
 
+#[derive(Debug, Eq, PartialEq, serde::Deserialize, serde::Serialize)]
+#[serde(rename_all = "camelCase")]
+pub enum TransactionOptions {
+    ReadOnly {
+        read_time: String,
+    },
+    ReadWrite {
+        #[serde(skip_serializing_if = "Option::is_none")]
+        retry_transaction: Option<String>,
+    },
+}
+
+#[derive(Debug, Eq, PartialEq, serde::Deserialize, serde::Serialize)]
+pub struct BeginTransactionRequestBody {
+    pub options: TransactionOptions,
+}
+
+#[derive(Debug, Eq, PartialEq, serde::Deserialize, serde::Serialize)]
+pub struct BeginTransactionResponse {
+    pub transaction: String,
+}
+
+pub async fn begin_transaction(
+    (token, project_id): (&str, &str),
+    database: &str,
+    body: BeginTransactionRequestBody,
+) -> anyhow::Result<Response> {
+    // <https://cloud.google.com/firestore/docs/reference/rest/v1/projects.databases.documents/beginTransaction>
+    let method = Method::POST;
+    let url = format!(
+        "https://firestore.googleapis.com/v1/{}/documents:beginTransaction",
+        database
+    );
+
+    Ok(Client::new()
+        .request(method, url)
+        .header("Authorization", format!("Bearer {}", token))
+        .header("Content-Type", "application/json")
+        .header("X-Goog-User-Project", project_id)
+        .body(serde_json::to_string(&body)?)
+        .send()
+        .await?)
+}
+
 pub async fn create_document(
     (token, project_id): (&str, &str),
     parent: &str,
@@ -397,4 +441,33 @@ mod tests {
         assert!(serde_json::to_string(&document).is_ok());
         Ok(())
     }
+
+    #[test]
+    fn begin_transaction_request_body_test() -> anyhow::Result<()> {
+        assert_eq!(
+            serde_json::to_string(&BeginTransactionRequestBody {
+                options: TransactionOptions::ReadWrite {
+                    retry_transaction: None,
+                },
+            })?,
+            r#"{"options":{"readWrite":{}}}"#
+        );
+        assert_eq!(
+            serde_json::to_string(&BeginTransactionRequestBody {
+                options: TransactionOptions::ReadWrite {
+                    retry_transaction: Some("abc".to_owned()),
+                },
+            })?,
+            r#"{"options":{"readWrite":{"retry_transaction":"abc"}}}"#
+        );
+        assert_eq!(
+            serde_json::to_string(&BeginTransactionRequestBody {
+                options: TransactionOptions::ReadOnly {
+                    read_time: "2000-01-02T03:04:05Z".to_owned()
+                }
+            })?,
+            r#"{"options":{"readOnly":{"read_time":"2000-01-02T03:04:05Z"}}}"#
+        );
+        Ok(())
+    }
 }
diff --git a/twiq/crates/db/src/lib.rs b/twiq/crates/db/src/lib.rs
index d65e999f..8d245148 100644
--- a/twiq/crates/db/src/lib.rs
+++ b/twiq/crates/db/src/lib.rs
@@ -11,7 +11,29 @@ use std::{collections::HashMap, env};
 use anyhow::ensure;
 use reqwest::Response;
 
-use crate::firestore_rest::{Document, Value};
+use crate::firestore_rest::{
+    BeginTransactionRequestBody, BeginTransactionResponse, Document, TransactionOptions, Value,
+};
+
+async fn begin_transaction_example() -> anyhow::Result<BeginTransactionResponse> {
+    let bearer_token = env::var("GOOGLE_BEARER_TOKEN")?;
+    let project_id = env::var("PROJECT_ID")?;
+    let database_id = "(default)";
+    let database = format!("projects/{}/databases/{}", project_id, database_id);
+    let response = firestore_rest::begin_transaction(
+        (&bearer_token, &project_id),
+        &database,
+        BeginTransactionRequestBody {
+            options: TransactionOptions::ReadWrite {
+                retry_transaction: None,
+            },
+        },
+    )
+    .await?;
+    ensure!(response.status() == 200);
+    let response: BeginTransactionResponse = response.json().await?;
+    Ok(response)
+}
 
 // select (one)
 async fn get_example() -> anyhow::Result<Document> {
@@ -106,14 +128,17 @@ mod tests {
     use super::*;
 
     #[tokio::test]
+    #[ignore]
     async fn test() -> anyhow::Result<()> {
+        let response = begin_transaction_example().await?;
+        assert_eq!(serde_json::to_string(&response)?, "");
         // let response = create_document_example().await?;
         // let status = response.status();
         // assert_eq!(status, 200);
 
         // let response = patch_example().await?;
-        let document = get_example().await?;
-        assert_eq!(serde_json::to_string(&document)?, "");
+        // let document = get_example().await?;
+        // assert_eq!(serde_json::to_string(&document)?, "");
         Ok(())
     }
 }