feat: add memory usage module (#403)

Adds a module to display system memory and swap usage.

Cargo.lock

@@ -108,6 +108,11 @@ dependencies = [
  "constant_time_eq 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "byte-unit"
+version = "3.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "c2-chacha"
 version = "0.2.2"
@@ -242,6 +247,11 @@ dependencies = [
  "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "doc-comment"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "either"
 version = "1.5.2"
@@ -727,6 +737,7 @@ version = "0.19.0"
 dependencies = [
  "ansi_term 0.12.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "battery 0.7.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "byte-unit 3.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "chrono 0.4.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "clap 2.33.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "dirs 2.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -738,6 +749,7 @@ dependencies = [
  "pretty_env_logger 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rayon 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.40 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sysinfo 0.9.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "tempfile 3.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "toml 0.5.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicode-segmentation 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -769,6 +781,18 @@ dependencies = [
  "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "sysinfo"
+version = "0.9.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "cfg-if 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "doc-comment 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.62 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rayon 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "tempfile"
 version = "3.1.0"
@@ -959,6 +983,7 @@ dependencies = [
 "checksum battery 0.7.4 (registry+https://github.com/rust-lang/crates.io-index)" = "7a6d6fe5630049e900227cd89afce4c1204b88ec8e61a2581bb96fcce26f047b"
 "checksum bitflags 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3d155346769a6855b86399e9bc3814ab343cd3d62c7e985113d46a0ec3c281fd"
 "checksum blake2-rfc 0.2.18 (registry+https://github.com/rust-lang/crates.io-index)" = "5d6d530bdd2d52966a6d03b7a964add7ae1a288d25214066fd4b600f0f796400"
+"checksum byte-unit 3.0.3 (registry+https://github.com/rust-lang/crates.io-index)" = "6894a79550807490d9f19a138a6da0f8830e70c83e83402dd23f16fd6c479056"
 "checksum c2-chacha 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "7d64d04786e0f528460fc884753cf8dddcc466be308f6026f8e355c41a0e4101"
 "checksum cc 1.0.45 (registry+https://github.com/rust-lang/crates.io-index)" = "4fc9a35e1f4290eb9e5fc54ba6cf40671ed2a2514c3eeb2b2a908dda2ea5a1be"
 "checksum cfg-if 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)" = "11d43355396e872eefb45ce6342e4374ed7bc2b3a502d1b28e36d6e23c05d1f4"
@@ -974,6 +999,7 @@ dependencies = [
 "checksum crossbeam-utils 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)" = "f8306fcef4a7b563b76b7dd949ca48f52bc1141aa067d2ea09565f3e2652aa5c"
 "checksum dirs 2.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "13aea89a5c93364a98e9b37b2fa237effbb694d5cfe01c5b70941f7eb087d5e3"
 "checksum dirs-sys 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)" = "afa0b23de8fd801745c471deffa6e12d248f962c9fd4b4c33787b055599bde7b"
+"checksum doc-comment 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "923dea538cea0aa3025e8685b20d6ee21ef99c4f77e954a30febbaac5ec73a97"
 "checksum either 1.5.2 (registry+https://github.com/rust-lang/crates.io-index)" = "5527cfe0d098f36e3f8839852688e63c8fff1c90b2b405aef730615f9a7bcf7b"
 "checksum env_logger 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)" = "aafcde04e90a5226a6443b7aabdb016ba2f8307c847d524724bd9b346dd1a2d3"
 "checksum failure 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "795bd83d3abeb9220f257e597aa0080a508b27533824adf336529648f6abf7e2"
@@ -1040,6 +1066,7 @@ dependencies = [
 "checksum strsim 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)" = "8ea5119cdb4c55b55d432abb513a0429384878c15dde60cc77b1c99de1a95a6a"
 "checksum syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)" = "a1393e4a97a19c01e900df2aec855a29f71cf02c402e2f443b8d2747c25c5dbe"
 "checksum synstructure 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)" = "73687139bf99285483c96ac0add482c3776528beac1d97d444f6e91f203a2015"
+"checksum sysinfo 0.9.5 (registry+https://github.com/rust-lang/crates.io-index)" = "d5bd3b813d94552a8033c650691645f8dd5a63d614dddd62428a95d3931ef7b6"
 "checksum tempfile 3.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "7a6e24d9338a0a5be79593e2fa15a648add6138caa803e2d5bc782c371732ca9"
 "checksum termcolor 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "4096add70612622289f2fdcdbd5086dc81c1e2675e6ae58d6c4f62a16c6d7f2f"
 "checksum termion 1.5.2 (registry+https://github.com/rust-lang/crates.io-index)" = "dde0593aeb8d47accea5392b39350015b5eccb12c0d98044d856983d89548dea"

Cargo.toml

@@ -42,6 +42,8 @@ unicode-segmentation = "1.3.0"
 gethostname = "0.2.0"
 once_cell = "1.2.0"
 chrono = "0.4"
+sysinfo = "0.9.5"
+byte-unit = "3.0.3"
 
 [dev-dependencies]
 tempfile = "3.1.0"

docs/config/README.md

@@ -97,6 +97,7 @@ prompt_order = [
     "golang",
     "java",
     "nix_shell",
+    "memory_usage",
     "aws",
     "env_var",
     "cmd_duration",
@@ -571,6 +572,36 @@ impure_msg = "impure shell"
 pure_msg = "pure shell"
 ```
 
+## Memory Usage
+
+The `memory_usage` module shows current system memory and swap usage.
+
+By default the swap usage is displayed if the total system swap is non-zero.
+
+### Options
+
+| Variable          | Default                  | Description                                                   |
+| ----------------- | ------------------------ | ------------------------------------------------------------- |
+| `show_percentage` | `false`                  | Display memory usage as a percentage of the available memory. |
+| `show_swap`       | when total swap non-zero | Display swap usage.                                           |
+| `threshold`       | `75`                     | Hide the memory usage unless it exceeds this percentage.      |
+| `symbol`          | `"🐏 "`                  | The symbol used before displaying the memory usage.           |
+| `style`           | `"bold dimmed white"`    | The style for the module.                                     |
+| `disabled`        | `false`                  | Disables the `memory_usage` module.                           |
+
+### Example
+
+```toml
+# ~/.config/starship.toml
+
+[memory_usage]
+show_percentage = true
+show_swap = true
+threshold = -1
+icon = " "
+style = "bold dimmed green"
+```
+
 ## Java
 
 The `java` module shows the currently installed version of Java.

src/module.rs

@@ -21,6 +21,7 @@ pub const ALL_MODULES: &[&str] = &[
     "java",
     "jobs",
     "line_break",
+    "memory_usage",
     "nix_shell",
     "nodejs",
     "package",

src/modules/memory_usage.rs

@@ -0,0 +1,87 @@
+use ansi_term::Color;
+
+use super::{Context, Module};
+use byte_unit::{Byte, ByteUnit};
+use sysinfo::{RefreshKind, SystemExt};
+
+/// Creates a module with system memory usage information
+pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
+    const DEFAULT_THRESHOLD: i64 = 75;
+    const DEFAULT_SHOW_PERCENTAGE: bool = false;
+    const RAM_CHAR: &str = "🐏 ";
+
+    let mut module = context.new_module("memory_usage");
+
+    let module_style = module
+        .config_value_style("style")
+        .unwrap_or_else(|| Color::White.bold().dimmed());
+
+    let system = sysinfo::System::new_with_specifics(RefreshKind::new().with_system());
+
+    let used_memory_kib = system.get_used_memory();
+    let total_memory_kib = system.get_total_memory();
+    let used_swap_kib = system.get_used_swap();
+    let total_swap_kib = system.get_total_swap();
+
+    let percent_mem_used = (used_memory_kib as f64 / total_memory_kib as f64) * 100.;
+    let percent_swap_used = (used_swap_kib as f64 / total_swap_kib as f64) * 100.;
+
+    let threshold = module
+        .config_value_i64("threshold")
+        .unwrap_or(DEFAULT_THRESHOLD);
+
+    if percent_mem_used.round() < threshold as f64 {
+        return None;
+    }
+
+    let show_percentage = module
+        .config_value_bool("show_percentage")
+        .unwrap_or(DEFAULT_SHOW_PERCENTAGE);
+
+    let (display_mem, display_swap) = if show_percentage {
+        (
+            format!("{:.0}%", percent_mem_used),
+            format!("{:.0}%", percent_swap_used),
+        )
+    } else {
+        fn format_kib(n_kib: u64) -> String {
+            let byte = Byte::from_unit(n_kib as f64, ByteUnit::KiB)
+                .unwrap_or_else(|_| Byte::from_bytes(0));
+            let mut display_bytes = byte.get_appropriate_unit(true).format(0);
+            display_bytes.retain(|c| c != ' ');
+            display_bytes
+        }
+        (
+            format!(
+                "{}/{}",
+                format_kib(used_memory_kib),
+                format_kib(total_memory_kib)
+            ),
+            format!(
+                "{}/{}",
+                format_kib(used_swap_kib),
+                format_kib(total_swap_kib)
+            ),
+        )
+    };
+
+    let show_swap = module
+        .config_value_bool("show_swap")
+        .unwrap_or(total_swap_kib != 0);
+
+    module.new_segment("symbol", RAM_CHAR);
+
+    module.set_style(module_style);
+    if show_swap {
+        module.new_segment(
+            "memory_usage",
+            &format!("{} | {}", display_mem, display_swap),
+        );
+    } else {
+        module.new_segment("memory_usage", &display_mem);
+    }
+
+    module.get_prefix().set_value("");
+
+    Some(module)
+}

src/modules/mod.rs

@@ -12,6 +12,7 @@ mod hostname;
 mod java;
 mod jobs;
 mod line_break;
+mod memory_usage;
 mod nix_shell;
 mod nodejs;
 mod package;
@@ -52,6 +53,7 @@ pub fn handle<'a>(module: &str, context: &'a Context) -> Option<Module<'a>> {
         "nix_shell" => nix_shell::module(context),
         "hostname" => hostname::module(context),
         "time" => time::module(context),
+        "memory_usage" => memory_usage::module(context),
 
         _ => {
             eprintln!("Error: Unknown module {}. Use starship module --list to list out all supported modules.", module);

src/print.rs

@@ -26,6 +26,7 @@ const DEFAULT_PROMPT_ORDER: &[&str] = &[
     "golang",
     "java",
     "nix_shell",
+    "memory_usage",
     "aws",
     "env_var",
     "cmd_duration",