Add http_headers and http_path_prefix provider configuration options for HTTP proxy support

[cjoy]

Added two new provider configuration options to support HTTP proxy scenarios where custom headers or URL path rewriting are required:

• http_headers - A map of custom HTTP headers added to all API requests (marked as sensitive)
• http_path_prefix - A path prefix prepended to all API request URLs

Changes:

• Core Implementation (internal/providers/client/databricks_client.go):

  • Added HTTPConfig struct to hold custom headers and path prefix
  • Added httpTransportWrapper implementing http.RoundTripper that injects headers and prepends path prefix
  • Modified PrepareDatabricksClient to accept optional *HTTPConfig and configure HTTP transport

• SDKv2 Provider (internal/providers/sdkv2/sdkv2.go):

  • Added http_headers schema field (TypeMap, optional, sensitive)
  • Added http_path_prefix schema field (TypeString, optional)
  • Updated ConfigureDatabricksClient to read and pass HTTP config

• Plugin Framework Provider (internal/providers/pluginfw/pluginfw.go):

  • Added http_headers schema field (MapAttribute with StringType)
  • Added http_path_prefix schema field (StringAttribute)
  • Updated configureDatabricksClient to read and pass HTTP config

• Unit Tests:

  • internal/providers/client/databricks_client_test.go: Tests for httpTransportWrapper RoundTrip behavior
  • internal/providers/sdkv2/sdkv2_test.go: Schema validation and configuration tests

Implementation Details:

• Uses Go SDK's HTTPTransport field to inject a custom http.RoundTripper
• Headers are set on each request via req.Header.Set()
• Path prefix is prepended to req.URL.Path (trailing slashes are trimmed)
• Both SDKv2 and Plugin Framework providers share the same underlying client configuration
• http_headers is marked as sensitive to avoid logging credentials

Example Usage:

provider "databricks" {
  host  = "https://proxy.example.com"
  token = "your-token"

  http_headers = {
    "X-Custom-Auth" = "auth-value"
  }

  http_path_prefix = "/proxy"
}

Tests

• make test runs locally (2615 tests pass)
• relevant change in docs/ folder
• unit tests for HTTP transport wrapper and schema
• using Go SDK (config.HTTPTransport)
• using TF Plugin Framework
• has entry in NEXT_CHANGELOG.md file

[alexott]

IMHO, it should be done in Go SDK and only then exposed to TF

[cjoy]

IMHO, it should be done in Go SDK and only then exposed to TF

@alexott Fair point. I've raised a PR here: databricks/databricks-sdk-go#1340

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Trigger:
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Inputs:

• PR number: 5232
• Commit SHA: 51b81181319d99e26edfc8ffb758f5aba38b4fd6

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