STACKITCIN-299 Add support for derivedFields to Grafana TF module

grafana/Untitled111.md

@@ -1 +0,0 @@
-

grafana/datasource/datasource.tf

@@ -1,9 +1,13 @@
+# main.tf
+
+# Step 1: Create all Grafana data sources with their basic configuration.
+# This resource establishes the fundamental properties of each data source.
 resource "grafana_data_source" "this" {
   for_each = var.datasources
 
-  name       = each.key
+  name     = each.key
-  type       = each.value.type
+  type     = each.value.type
-  url        = var.datasource_urls[each.value.url_key]
+  url      = var.datasource_urls[each.value.url_key]
   is_default = coalesce(each.value.is_default, false)
 
   basic_auth_enabled  = true
@@ -13,5 +17,61 @@ resource "grafana_data_source" "this" {
     basicAuthPassword = var.datasource_passwords[each.value.pass_key]
   })
 
+  # Encodes initial, non-dependent JSON data.
+  # Configurations that depend on other datasource UIDs will be handled separately.
   json_data_encoded = each.value.json_data != null ? jsonencode(each.value.json_data) : null
 }
+
+# Step 2: Apply Loki-specific 'derivedFields' configuration.
+# This resource targets Loki data sources that need to link to another data source (like Tempo).
+# It runs after the initial data sources are created to resolve the UIDs.
+resource "grafana_data_source_config" "loki_derived_fields" {
+  # Filter for datasources that are of type 'loki' and have 'derived_fields' defined.
+  for_each = {
+    for k, v in var.datasources : k => v
+    if v.type == "loki" && v.derived_fields != null
+  }
+
+  # The UID of the Loki data source to configure.
+  uid = grafana_data_source.this[each.key].uid
+
+  # Construct the json_data with the derivedFields.
+  json_data_encoded = jsonencode({
+    derivedFields = [
+      for field in each.value.derived_fields : {
+        # The UID of the target data source (e.g., Tempo).
+        datasourceUid = grafana_data_source.this[field.target_datasource_name].uid
+        matcherRegex  = field.matcher_regex
+        name          = field.name
+        url           = field.url
+      }
+    ]
+  })
+}
+
+# Step 3: Apply Tempo-specific 'tracesToLogsV2' configuration.
+# This resource targets Tempo data sources that need to link back to a logging data source (like Loki).
+resource "grafana_data_source_config" "tempo_traces_to_logs" {
+  # Filter for datasources that are of type 'tempo' and have 'traces_to_logs' defined.
+  for_each = {
+    for k, v in var.datasources : k => v
+    if v.type == "tempo" && v.traces_to_logs != null
+  }
+
+  # The UID of the Tempo data source to configure.
+  uid = grafana_data_source.this[each.key].uid
+
+  # Construct the json_data with the tracesToLogsV2 settings.
+  json_data_encoded = jsonencode({
+    tracesToLogsV2 = {
+      # The UID of the target data source (e.g., Loki).
+      datasourceUid      = grafana_data_source.this[each.value.traces_to_logs.target_datasource_name].uid
+      query              = each.value.traces_to_logs.query
+      customQuery        = coalesce(each.value.traces_to_logs.custom_query, true)
+      filterBySpanID     = coalesce(each.value.traces_to_logs.filter_by_span_id, false)
+      filterByTraceID    = coalesce(each.value.traces_to_logs.filter_by_trace_id, false)
+      spanStartTimeShift = each.value.traces_to_logs.span_start_time_shift
+      spanEndTimeShift   = each.value.traces_to_logs.span_end_time_shift
+    }
+  })
+}

grafana/datasource/variables.tf

@@ -1,17 +1,38 @@
+# variables.tf
+
 # Define datasources (non-sensitive metadata only)
 variable "datasources" {
   description = <<EOT
 Map of datasources to create. Keys are datasource names.
-Each datasource specifies type (prometheus/loki), keys to lookup URL/user/password,
+Each datasource specifies type (prometheus/loki/tempo), keys to lookup URL/user/password,
-and optional is_default (true/false).
+and optional configurations for linking data sources.
 EOT
   type = map(object({
-    type       = string           # e.g., prometheus, loki
+    type       = string           # e.g., prometheus, loki, tempo
     url_key    = string           # key for URL lookup in datasource_urls map
     user_key   = string           # key for username lookup in datasource_users map
     pass_key   = string           # key for password lookup in datasource_passwords map
     is_default = optional(bool)   # true if this datasource should be Grafana default
-    json_data  = optional(map(any))
+    json_data  = optional(map(any)) # Initial, non-dependent JSON data
+
+    # Optional: For Loki, to link to a tracing datasource like Tempo.
+    derived_fields = optional(list(object({
+      target_datasource_name = string # The name of the target datasource (e.g., "tempo-main")
+      matcher_regex          = string # Regex to find the trace ID in logs.
+      name                   = string # Name for the derived field (e.g., "traceID")
+      url                    = string # URL template, e.g., "$${__value.raw}"
+    })))
+
+    # Optional: For Tempo, to link to a logging datasource like Loki.
+    traces_to_logs = optional(object({
+      target_datasource_name = string # The name of the target datasource (e.g., "loki-main")
+      query                  = string # The query to run in the target datasource.
+      custom_query           = optional(bool)
+      filter_by_span_id      = optional(bool)
+      filter_by_trace_id     = optional(bool)
+      span_start_time_shift  = optional(string)
+      span_end_time_shift    = optional(string)
+    }))
   }))
 }