Move to single tracing-endpoint option

Kuadrant · Mar 18, 2024 · 0e3f68a · 0e3f68a
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diff --git a/doc/server/configuration.md b/doc/server/configuration.md
@@ -31,10 +31,8 @@ Options:
           Include the Limit Name in prometheus label
   -v...
           Sets the level of verbosity
-      --tracing-host <tracing_host>
-          The host for the tracing service
-      --tracing-port <tracing_port>
-          The port for the tracing service [default: 4317]
+      --tracing-endpoint <tracing_endpoint>
+          The endpoint for the tracing service
       --validate
           Validates the LIMITS_FILE and exits
   -H, --rate-limit-headers <rate_limit_headers>
@@ -47,7 +45,8 @@ Options:
           Print version
 ```
 
-The values used are authoritative over any [environment variables](#configuration-using-environment-variables) independently set.
+The values used are authoritative over any [environment variables](#configuration-using-environment-variables)
+independently set.
 
 ### Limit definitions
 
@@ -101,13 +100,13 @@ variables:
   - user_id
 ```
 
- - `namespace` namespaces the limit, will generally be the domain, [see here](../how-it-works.md)
- - `seconds` is the duration for which the limit applies, in seconds: e.g. `60` is a span of time of one minute
- - `max_value` is the actual limit, e.g. `100` would limit to 100 requests
- - `name` lets the user _optionally_ name the limit
- - `variables` is an array of variables, which once resolved, will be used to qualify counters for the limit,
-   e.g. `api_key` to limit per api keys
- - `conditions` is an array of conditions, which once evaluated will decide whether to apply the limit or not
+- `namespace` namespaces the limit, will generally be the domain, [see here](../how-it-works.md)
+- `seconds` is the duration for which the limit applies, in seconds: e.g. `60` is a span of time of one minute
+- `max_value` is the actual limit, e.g. `100` would limit to 100 requests
+- `name` lets the user _optionally_ name the limit
+- `variables` is an array of variables, which once resolved, will be used to qualify counters for the limit,
+  e.g. `api_key` to limit per api keys
+- `conditions` is an array of conditions, which once evaluated will decide whether to apply the limit or not
 
 #### `condition` syntax
 
@@ -116,9 +115,9 @@ Each `condition` is an expression producing a boolean value (`true` or `false`).
 
 Expressions follow the following syntax: `$IDENTIFIER $OP $STRING_LITERAL`, where:
 
- - `$IDENTIFIER` will be used to resolve the value at evaluation time, e.g. `role`
- - `$OP` is an operator, either `==` or `!=`
- - `$STRING_LITERAL` is a literal string value, `"` or `'` demarcated, e.g. `"admin"`
+- `$IDENTIFIER` will be used to resolve the value at evaluation time, e.g. `role`
+- `$OP` is an operator, either `==` or `!=`
+- `$STRING_LITERAL` is a literal string value, `"` or `'` demarcated, e.g. `"admin"`
 
 So that `role != "admin"` would apply the limit on request from all users, but `admin`'s.
 
@@ -281,7 +280,8 @@ For an in-depth coverage of the different topologies supported and how they affe
 ## Configuration using environment variables
 
 The Limitador server has some options that can be configured with environment variables. These will override the
-_default_ values the server uses. [Any argument](#command-line-configuration) used when starting the server will prevail over the
+_default_ values the server uses. [Any argument](#command-line-configuration) used when starting the server will prevail
+over the
 environment variables.
 
 #### `ENVOY_RLS_HOST`
@@ -290,137 +290,120 @@ environment variables.
 - Optional. Defaults to `"0.0.0.0"`.
 - Format: `string`.
 
-
 #### `ENVOY_RLS_PORT`
 
 - Port where the Envoy RLS server listens.
 - Optional. Defaults to `8081`.
 - Format: `integer`.
 
-
 #### `HTTP_API_HOST`
 
 - Host where the HTTP server listens.
 - Optional. Defaults to `"0.0.0.0"`.
 - Format: `string`.
 
-
 #### `HTTP_API_PORT`
 
 - Port where the HTTP API listens.
 - Optional. Defaults to `8080`.
 - Format: `integer`.
 
-
 #### `LIMITS_FILE`
 
 - YAML file that contains the limits to create when Limitador boots. If the
-limits specified already have counters associated, Limitador will not delete them.
-Changes to the file will be picked up by the running server.
+  limits specified already have counters associated, Limitador will not delete them.
+  Changes to the file will be picked up by the running server.
 - *Required*. No default
 - Format: `string`, file path.
 
-
 #### `LIMIT_NAME_IN_PROMETHEUS_LABELS`
 
 - Enables using limit names as labels in Prometheus metrics. This is disabled by
-default because for a few limits it should be fine, but it could become a
-problem when defining lots of limits. See the caution note in the [Prometheus
-docs](https://prometheus.io/docs/practices/naming/#labels)
+  default because for a few limits it should be fine, but it could become a
+  problem when defining lots of limits. See the caution note in the [Prometheus
+  docs](https://prometheus.io/docs/practices/naming/#labels)
 - Optional. Disabled by default.
 - Format: `bool`, set to `"1"` to enable.
 
-#### `TRACING_HOST`
+#### `TRACING_ENDPOINT`
 
-- Host of the OTLP tracing collector.
+- The endpoint of the OTLP tracing collector (scheme://host:port).
 - Optional. Default to `""` (tracing disabled)
 - Format: `string`
 
-#### `TRACING_PORT`
-
-- Port of the OTLP tracing collector.
-- Optional. Defaults to `4317`.
-- Format: `integer`.
-
 #### `REDIS_LOCAL_CACHE_ENABLED`
 
 - Enables a storage implementation that uses Redis, but also caches some data in
-memory. The idea is to improve throughput and latencies by caching the counters
-in memory to reduce the number of accesses to Redis. To achieve that, this mode
-sacrifices some rate-limit accuracy. This mode does two things:
+  memory. The idea is to improve throughput and latencies by caching the counters
+  in memory to reduce the number of accesses to Redis. To achieve that, this mode
+  sacrifices some rate-limit accuracy. This mode does two things:
     - Batches counter updates. Instead of updating the counters on every
-    request, it updates them in memory and commits them to Redis in batches. The
-    flushing interval can be configured with the
-    [`REDIS_LOCAL_CACHE_FLUSHING_PERIOD_MS`](#redis_local_cache_flushing_period_ms)
-    env. The trade-off is that when running several instances of Limitador,
-    other instances will not become aware of the counter updates until they're
-    committed to Redis.
+      request, it updates them in memory and commits them to Redis in batches. The
+      flushing interval can be configured with the
+      [`REDIS_LOCAL_CACHE_FLUSHING_PERIOD_MS`](#redis_local_cache_flushing_period_ms)
+      env. The trade-off is that when running several instances of Limitador,
+      other instances will not become aware of the counter updates until they're
+      committed to Redis.
     - Caches counters. Instead of fetching the value of a counter every time
-    it's needed, the value is cached for a configurable period. The trade-off is
-    that when running several instances of Limitador, an instance will not
-    become aware of the counter updates other instances do while the value is
-    cached. When a counter is already at 0 (limit exceeded), it's cached until
-    it expires in Redis. In this case, no matter what other instances do, we
-    know that the quota will not be reestablished until the key expires in
-    Redis, so in this case, rate-limit accuracy is not affected. When a counter
-    has still some quota remaining the situation is different, that's why we can
-    tune for how long it will be cached. The formula is as follows:
-    MIN(ttl_in_redis/[`REDIS_LOCAL_CACHE_TTL_RATIO_CACHED_COUNTERS`](#redis_local_cache_ttl_ratio_cached_counters),
-    [`REDIS_LOCAL_CACHE_MAX_TTL_CACHED_COUNTERS_MS`](#redis_local_cache_max_ttl_cached_counters_ms)).
-    For example, let's image that the current TTL (time remaining until the
-    limit resets) in Redis for a counter is 10 seconds, and we set the ratio to
-    2, and the max time for 30s. In this case, the counter will be cached for 5s
-    (min(10/2, 30)). During those 5s, Limitador will not fetch the value of that
-    counter from Redis, so it will answer faster, but it will also miss the
-    updates done by other instances, so it can go over the limits in that 5s
-    interval.
+      it's needed, the value is cached for a configurable period. The trade-off is
+      that when running several instances of Limitador, an instance will not
+      become aware of the counter updates other instances do while the value is
+      cached. When a counter is already at 0 (limit exceeded), it's cached until
+      it expires in Redis. In this case, no matter what other instances do, we
+      know that the quota will not be reestablished until the key expires in
+      Redis, so in this case, rate-limit accuracy is not affected. When a counter
+      has still some quota remaining the situation is different, that's why we can
+      tune for how long it will be cached. The formula is as follows:
+      MIN(ttl_in_redis/[`REDIS_LOCAL_CACHE_TTL_RATIO_CACHED_COUNTERS`](#redis_local_cache_ttl_ratio_cached_counters),
+      [`REDIS_LOCAL_CACHE_MAX_TTL_CACHED_COUNTERS_MS`](#redis_local_cache_max_ttl_cached_counters_ms)).
+      For example, let's image that the current TTL (time remaining until the
+      limit resets) in Redis for a counter is 10 seconds, and we set the ratio to
+      2, and the max time for 30s. In this case, the counter will be cached for 5s
+      (min(10/2, 30)). During those 5s, Limitador will not fetch the value of that
+      counter from Redis, so it will answer faster, but it will also miss the
+      updates done by other instances, so it can go over the limits in that 5s
+      interval.
 - Optional. Disabled by default.
 - Format: set to "1" to enable.
 - Note: "REDIS_URL" needs to be set.
 
-
 #### `REDIS_LOCAL_CACHE_FLUSHING_PERIOD_MS`
 
 - Used to configure the local cache when using Redis. See
-[`REDIS_LOCAL_CACHE_ENABLED`](#redis_local_cache_enabled). This env only applies
-when `"REDIS_LOCAL_CACHE_ENABLED" == 1`.
+  [`REDIS_LOCAL_CACHE_ENABLED`](#redis_local_cache_enabled). This env only applies
+  when `"REDIS_LOCAL_CACHE_ENABLED" == 1`.
 - Optional. Defaults to `1000`.
 - Format: `integer`. Duration in milliseconds.
 
-
 #### `REDIS_LOCAL_CACHE_MAX_TTL_CACHED_COUNTERS_MS`
 
 - Used to configure the local cache when using Redis. See
-[`REDIS_LOCAL_CACHE_ENABLED`](#redis_local_cache_enabled). This env only applies
-when `"REDIS_LOCAL_CACHE_ENABLED" == 1`.
+  [`REDIS_LOCAL_CACHE_ENABLED`](#redis_local_cache_enabled). This env only applies
+  when `"REDIS_LOCAL_CACHE_ENABLED" == 1`.
 - Optional. Defaults to `5000`.
 - Format: `integer`. Duration in milliseconds.
 
-
 #### `REDIS_LOCAL_CACHE_TTL_RATIO_CACHED_COUNTERS`
 
 - Used to configure the local cache when using Redis. See
-[`REDIS_LOCAL_CACHE_ENABLED`](#redis_local_cache_enabled). This env only applies
-when `"REDIS_LOCAL_CACHE_ENABLED" == 1`.
+  [`REDIS_LOCAL_CACHE_ENABLED`](#redis_local_cache_enabled). This env only applies
+  when `"REDIS_LOCAL_CACHE_ENABLED" == 1`.
 - Optional. Defaults to `10`.
 - Format: `integer`.
 
-
 #### `REDIS_URL`
 
 - Redis URL. Required only when you want to use Redis to store the limits.
 - Optional. By default, Limitador stores the limits in memory and does not
-require Redis.
+  require Redis.
 - Format: `string`, URL in the format of `"redis://127.0.0.1:6379"`.
 
-
 #### `RUST_LOG`
 
 - Defines the log level.
 - Optional. Defaults to `"error"`.
 - Format: `enum`: `"debug"`, `"error"`, `"info"`, `"warn"`, or `"trace"`.
 
-
 ### When built with the `infinispan` feature - _experimental_
 
 #### `INFINISPAN_CACHE_NAME`
@@ -431,15 +414,13 @@ require Redis.
 - Optional. By default, Limitador will use a cache called `"limitador"`.
 - Format: `string`.
 
-
 #### `INFINISPAN_COUNTERS_CONSISTENCY`
 
 - Defines the consistency mode for the Infinispan counters created by Limitador.
   This variable applies only when [`INFINISPAN_URL`](#infinispan_url) is set.
 - Optional. Defaults to `"strong"`.
 - Format: `enum`: `"Strong"` or `"Weak"`.
 
-
 #### `INFINISPAN_URL`
 
 - Infinispan URL. Required only when you want to use Infinispan to store the
@@ -448,12 +429,12 @@ require Redis.
   require Infinispan.
 - Format: `URL`, in the format of `http://username:[email protected]:11222`.
 
-
 #### `RATE_LIMIT_HEADERS`
 
 - Enables rate limit response headers. Only supported by the RLS server.
 - Optional. Defaults to `"NONE"`.
 - Must be one of:
-  - `"NONE"` - Does not add any additional headers to the http response.
-  - `"DRAFT_VERSION_03"`.  Adds response headers per https://datatracker.ietf.org/doc/id/draft-polli-ratelimit-headers-03.html
+    - `"NONE"` - Does not add any additional headers to the http response.
+    - `"DRAFT_VERSION_03"`. Adds response headers
+      per https://datatracker.ietf.org/doc/id/draft-polli-ratelimit-headers-03.html
 
diff --git a/limitador-server/src/config.rs b/limitador-server/src/config.rs
@@ -31,8 +31,7 @@ pub struct Configuration {
     http_host: String,
     http_port: u16,
     pub limit_name_in_labels: bool,
-    pub tracing_host: String,
-    tracing_port: u16,
+    pub tracing_endpoint: String,
     pub log_level: Option<LevelFilter>,
     pub rate_limit_headers: RateLimitHeaders,
     pub grpc_reflection_service: bool,
@@ -47,8 +46,7 @@ pub mod env {
         pub static ref ENVOY_RLS_PORT: Option<&'static str> = value_for("ENVOY_RLS_PORT");
         pub static ref HTTP_API_HOST: Option<&'static str> = value_for("HTTP_API_HOST");
         pub static ref HTTP_API_PORT: Option<&'static str> = value_for("HTTP_API_PORT");
-        pub static ref TRACING_HOST: Option<&'static str> = value_for("TRACING_HOST");
-        pub static ref TRACING_PORT: Option<&'static str> = value_for("TRACING_PORT");
+        pub static ref TRACING_ENDPOINT: Option<&'static str> = value_for("TRACING_ENDPOINT");
         pub static ref DISK_PATH: Option<&'static str> = value_for("DISK_PATH");
         pub static ref DISK_OPTIMIZE: Option<&'static str> = value_for("DISK_OPTIMIZE");
         pub static ref REDIS_URL: Option<&'static str> = value_for("REDIS_URL");
@@ -76,7 +74,6 @@ pub mod env {
 impl Configuration {
     pub const DEFAULT_RLS_PORT: &'static str = "8081";
     pub const DEFAULT_HTTP_PORT: &'static str = "8080";
-    pub const DEFAULT_TRACING_PORT: &'static str = "4317";
     pub const DEFAULT_IP_BIND: &'static str = "0.0.0.0";
 
     #[allow(clippy::too_many_arguments)]
@@ -88,8 +85,7 @@ impl Configuration {
         http_host: String,
         http_port: u16,
         limit_name_in_labels: bool,
-        tracing_host: String,
-        tracing_port: u16,
+        tracing_endpoint: String,
         rate_limit_headers: RateLimitHeaders,
         grpc_reflection_service: bool,
     ) -> Self {
@@ -101,8 +97,7 @@ impl Configuration {
             http_host,
             http_port,
             limit_name_in_labels,
-            tracing_host,
-            tracing_port,
+            tracing_endpoint,
             log_level: None,
             rate_limit_headers,
             grpc_reflection_service,
@@ -116,10 +111,6 @@ impl Configuration {
     pub fn http_address(&self) -> String {
         format!("{}:{}", self.http_host, self.http_port)
     }
-
-    pub fn tracing_address(&self) -> String {
-        format!("{}:{}", self.tracing_host, self.tracing_port)
-    }
 }
 
 #[cfg(test)]
@@ -135,8 +126,7 @@ impl Default for Configuration {
             http_host: "".to_string(),
             http_port: 0,
             limit_name_in_labels: false,
-            tracing_host: "".to_string(),
-            tracing_port: 0,
+            tracing_endpoint: "".to_string(),
             log_level: None,
             rate_limit_headers: RateLimitHeaders::None,
             grpc_reflection_service: false,