Add a new optional parameter in BigTableConnection constructor for re…

…ading Service Worker JSON. (#63)

* Add new BigTableConnection constructor for reading Service Worker json

* Created new function to allow file path

* Remove simulation from new_with_path function

* Remove whitespace

* Refactor to a single reusable function

* Remove unwanted use crate

* Add a short description to the function

* Add an example on how to use  and shift of emulator logic to new_with_auth_manager

* Remove unwanted use crate

* format code using cargo fmt

bigtable_rs/src/bigtable.rs

@@ -215,6 +215,43 @@ impl BigTableConnection {
         is_read_only: bool,
         channel_size: usize,
         timeout: Option<Duration>,
+    ) -> Result<Self> {
+        let authentication_manager = AuthenticationManager::new().await?;
+        Self::new_with_auth_manager(
+            project_id,
+            instance_name,
+            is_read_only,
+            channel_size,
+            timeout,
+            authentication_manager,
+        )
+        .await
+    }
+    /// Establish a connection to the BigTable instance named `instance_name`.  If read-only access
+    /// is required, the `read_only` flag should be used to reduce the requested OAuth2 scope.
+    ///
+    /// The `authentication_manager` variable will be used to determine the
+    /// program name that contains the BigTable instance in addition to access credentials.
+    ///
+    ///
+    /// `channel_size` defines the number of connections (or channels) established to Bigtable
+    /// service, and the requests are load balanced onto all the channels. You must therefore
+    /// make sure all of these connections are open when a new request is to be sent.
+    /// Idle connections are automatically closed in "a few minutes". Therefore it is important to
+    /// make sure you have a high enough QPS to send at least one request through all the
+    /// connections (in every service host) every minute. If not, you should consider decreasing the
+    /// channel size. If you are not sure what value to pick and your load is low, just start with 1.
+    /// The recommended value could be 2 x the thread count in your tokio environment see info here
+    /// https://docs.rs/tokio/latest/tokio/attr.main.html, but it might be a very different case for
+    /// different applications.
+    ///
+    pub async fn new_with_auth_manager(
+        project_id: &str,
+        instance_name: &str,
+        is_read_only: bool,
+        channel_size: usize,
+        timeout: Option<Duration>,
+        authentication_manager: AuthenticationManager,
     ) -> Result<Self> {
         match std::env::var("BIGTABLE_EMULATOR_HOST") {
             Ok(endpoint) => {
@@ -247,8 +284,6 @@ impl BigTableConnection {
             }
 
             Err(_) => {
-                let authentication_manager = AuthenticationManager::new().await?;
-
                 let table_prefix = format!(
                     "projects/{}/instances/{}/tables/",
                     project_id, instance_name

examples/Cargo.toml

@@ -21,6 +21,10 @@ path = "src/simple_write.rs"
 name = "http_server"
 path = "src/http_server/http_server.rs"
 
+[[bin]]
+name = "custom_path_connection"
+path = "src/custom_path_connection.rs"
+
 [[bin]]
 name = "prefix"
 path = "src/prefix.rs"
@@ -33,3 +37,4 @@ log = "0.4.20"
 warp = "0.3.6"
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
+gcp_auth = "0.9.0"

examples/src/custom_path_connection.rs

@@ -0,0 +1,88 @@
+use bigtable_rs::bigtable;
+use bigtable_rs::google::bigtable::v2::mutation;
+use bigtable_rs::google::bigtable::v2::mutation::SetCell;
+use bigtable_rs::google::bigtable::v2::row_filter::Filter;
+use bigtable_rs::google::bigtable::v2::{
+    MutateRowRequest, Mutation, ReadRowsRequest, RowFilter, RowSet,
+};
+use env_logger;
+use gcp_auth::{AuthenticationManager, CustomServiceAccount};
+use std::error::Error;
+use std::time::Duration;
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn Error>> {
+    env_logger::init();
+
+    let project_id = "project-1";
+    let instance_name = "instance-1";
+    let table_name = "table-1";
+    let channel_size = 4;
+    let timeout = Duration::from_secs(10);
+
+    let key: String = "key3".to_owned();
+
+    let json_path: &str = "path/to/json";
+    // make a bigtable client
+    let connection = bigtable::BigTableConnection::new_with_auth_manager(
+        project_id,
+        instance_name,
+        false,
+        channel_size,
+        Some(timeout),
+        AuthenticationManager::from(CustomServiceAccount::from_file(json_path).unwrap()),
+    )
+    .await?;
+    let mut bigtable = connection.client();
+
+    let request = MutateRowRequest {
+        table_name: bigtable.get_full_table_name(table_name),
+        row_key: key.clone().into_bytes(),
+        mutations: vec![Mutation {
+            mutation: Some(mutation::Mutation::SetCell(SetCell {
+                family_name: "cf1".to_owned(),
+                column_qualifier: "c1".to_owned().into_bytes(),
+                timestamp_micros: -1, // IMPORTANT: Don't leave it empty. Use -1 for current Bigtable server time.
+                value: "a new write value".to_owned().into_bytes(),
+            })),
+        }],
+        ..MutateRowRequest::default()
+    };
+
+    // write to table
+    let _response = bigtable.mutate_row(request).await?;
+
+    // read from table again
+    // prepare a ReadRowsRequest
+    let request = ReadRowsRequest {
+        table_name: bigtable.get_full_table_name(table_name),
+        rows_limit: 10,
+        rows: Some(RowSet {
+            row_keys: vec![key.clone().into_bytes()],
+            row_ranges: vec![],
+        }),
+        filter: Some(RowFilter {
+            filter: Some(Filter::CellsPerColumnLimitFilter(1)),
+        }),
+        ..ReadRowsRequest::default()
+    };
+
+    // calling bigtable API to get results
+    let response = bigtable.read_rows(request).await?;
+
+    // simply print results for example usage
+    response.into_iter().for_each(|(key, data)| {
+        println!("------------\n{}", String::from_utf8(key.clone()).unwrap());
+        data.into_iter().for_each(|row_cell| {
+            println!(
+                "    [{}:{}] \"{}\" @ {}",
+                row_cell.family_name,
+                String::from_utf8(row_cell.qualifier).unwrap(),
+                String::from_utf8(row_cell.value).unwrap(),
+                row_cell.timestamp_micros
+            )
+        })
+    });
+
+    Ok(())
+}