Class: Parse::Embeddings::LocalHTTP

Inherits:
Provider
  • Object
show all
Defined in:
lib/parse/embeddings/local_http.rb

Overview

Generic OpenAI-compatible local embedding provider. Talks to any server that exposes POST <base_url>/embeddings with the OpenAI request/response shape — covers Ollama (/v1), LM Studio (/v1), vLLM, llama.cpp's server, and any reverse-proxy that translates to a local model runner.

== SSRF gate

The base_url is resolved at construction time and the resolved addresses are checked against File::BLOCKED_CIDRS (loopback, RFC1918, link-local, cloud-metadata, CGNAT, IPv6 ULA, …). When ANY resolved address falls in a private/internal range, the constructor refuses unless the caller opts in via allow_private_endpoint: true.

The opt-in is a deliberate, audit-able gate — Parse::Embeddings registration is configuration code, not user input, so opting in to "yes, this base_url really is my Ollama on localhost" is a one-line decision by the operator at boot time. A Kernel#warn fires when the opt-in is taken so the choice shows up in operator logs / bundle exec rake about output.

http:// base URLs are accepted with allow_private_endpoint: true (the typical local-runner deployment), and refused otherwise unless the caller also passes allow_insecure_base_url: true (escape hatch for self-signed internal HTTPS proxies fronted by http://).

== Why no fixed model whitelist

Ollama, LM Studio, and vLLM all serve operator-chosen models — we cannot enumerate "supported" models the way OpenAI can. The constructor instead takes the dimensions: explicitly, and the provider's Provider#validate_response! (inherited) enforces that every returned vector matches that width. Mis-specified dimensions surface as InvalidResponseError on the first embed call.

== Security

  • Configure-time SSRF gate (above).
  • The Faraday connection refuses proxy: unless the caller opts in via allow_faraday_proxy: true. Env-proxy autodiscovery is suppressed by default — same model as OpenAI.
  • #inspect (inherited from Provider) never surfaces @api_key.

Examples:

Ollama on the same host

Parse::Embeddings.register(:ollama,
  Parse::Embeddings::LocalHTTP.new(
    base_url: "http://localhost:11434/v1",
    model: "nomic-embed-text",
    dimensions: 768,
    allow_private_endpoint: true,
  ))

public OpenAI-compatible proxy (e.g. internal gateway on a public DNS name)

Parse::Embeddings.register(:gateway,
  Parse::Embeddings::LocalHTTP.new(
    base_url: "https://embeddings.example.com/v1",
    api_key:  ENV.fetch("GATEWAY_API_KEY"),
    model:    "bge-small-en-v1.5",
    dimensions: 384,
  ))

Defined Under Namespace

Classes: AuthenticationError, BadRequestError, RateLimitError, TransientError

Constant Summary collapse

DEFAULT_TIMEOUT = 
30
DEFAULT_OPEN_TIMEOUT = 
5
DEFAULT_MAX_RETRIES = 
3
DEFAULT_BATCH_SIZE = 
32
MAX_RESPONSE_BYTES = 
16 * 1024 * 1024

Constants inherited from Provider

Provider::AS_NOTIFICATION_NAME

Instance Method Summary collapse

Methods inherited from Provider

#embed_image, #embed_text_batched, #inspect, #instrument_embed, #max_input_tokens, #modalities, #validate_response!

Constructor Details

#initialize(base_url:, model:, dimensions:, api_key: nil, normalize: false, timeout: DEFAULT_TIMEOUT, open_timeout: DEFAULT_OPEN_TIMEOUT, max_retries: DEFAULT_MAX_RETRIES, embed_batch_size: DEFAULT_BATCH_SIZE, allow_private_endpoint: false, allow_insecure_base_url: false, allow_faraday_proxy: false, connection: nil) ⇒ LocalHTTP

Returns a new instance of LocalHTTP.

Parameters:

  • base_url (String) —

    required. Must be http(s):// with a host.

  • model (String) —

    required. Identifier the local server expects in the model request field. Persisted to embedding_meta.

  • dimensions (Integer) —

    required. Width of vectors the local model produces. Enforced by Provider#validate_response!.

  • api_key (String, nil) (defaults to: nil) —

    optional. When present, sent as Authorization: Bearer …. Local runners typically accept any value or no header.

  • normalize (Boolean) (defaults to: false) —

    whether the local model returns unit-normalized vectors. Defaults to false (Ollama and most local models do NOT normalize; bge-* and OpenAI do). Affects similarity metric selection downstream.

  • timeout (Integer) (defaults to: DEFAULT_TIMEOUT) —

    read timeout, seconds.

  • open_timeout (Integer) (defaults to: DEFAULT_OPEN_TIMEOUT) —

    connect timeout, seconds.

  • max_retries (Integer) (defaults to: DEFAULT_MAX_RETRIES) —

    retry attempts on 429/5xx/timeouts.

  • embed_batch_size (Integer) (defaults to: DEFAULT_BATCH_SIZE) —

    inputs per request.

  • allow_private_endpoint (Boolean) (defaults to: false) —

    required when base_url resolves to a private/internal/loopback address. Defaults false; opting in emits a one-time warning per provider instance.

  • allow_insecure_base_url (Boolean) (defaults to: false) —

    permit http:// for PUBLIC base URLs. Defaults false. Independent of allow_private_endpoint (which already implies http:// is fine for the local case).

  • allow_faraday_proxy (Boolean) (defaults to: false) —

    opt in to proxy / env-proxy autodiscovery. Defaults false.

  • connection (Faraday::Connection, nil) (defaults to: nil) —

    injection seam.



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# File 'lib/parse/embeddings/local_http.rb', line 114

def initialize(
  base_url:,
  model:,
  dimensions:,
  api_key: nil,
  normalize: false,
  timeout: DEFAULT_TIMEOUT,
  open_timeout: DEFAULT_OPEN_TIMEOUT,
  max_retries: DEFAULT_MAX_RETRIES,
  embed_batch_size: DEFAULT_BATCH_SIZE,
  allow_private_endpoint: false,
  allow_insecure_base_url: false,
  allow_faraday_proxy: false,
  connection: nil
)
  validate_model!(model)
  validate_dimensions!(dimensions)
  validate_optional_api_key!(api_key)
  unless [true, false].include?(normalize)
    raise ArgumentError,
          "Parse::Embeddings::LocalHTTP: normalize must be true or false (got #{normalize.inspect})."
  end
  validate_positive_integer!(:timeout, timeout)
  validate_positive_integer!(:open_timeout, open_timeout)
  validate_non_negative_integer!(:max_retries, max_retries)
  validate_positive_integer!(:embed_batch_size, embed_batch_size)

  sanitized_base_url, resolved_addrs, is_private =
    validate_base_url_and_gate_ssrf!(base_url,
                                     allow_private_endpoint: allow_private_endpoint,
                                     allow_insecure_base_url: allow_insecure_base_url)
  if is_private
    # Audit log. Emits once per instance — Kernel#warn so it lands
    # on stderr and any logger that captures it. Operators running
    # a hardened environment can grep this to confirm every
    # private-endpoint opt-in was intentional.
    warn "Parse::Embeddings::LocalHTTP: allow_private_endpoint=true for #{sanitized_base_url} — " \
         "resolved to private address(es) #{resolved_addrs.map(&:to_s).inspect}."
  end

  @base_url = sanitized_base_url
  @model = model
  @dimensions = dimensions
  @api_key = api_key
  @normalize = normalize
  @timeout = timeout
  @open_timeout = open_timeout
  @max_retries = max_retries
  @embed_batch_size = embed_batch_size
  @allow_faraday_proxy = allow_faraday_proxy
  @connection = connection || build_connection
end

Instance Method Details

#backoff_seconds(attempt) ⇒ Object (protected) 



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# File 'lib/parse/embeddings/local_http.rb', line 355

def backoff_seconds(attempt)
  [0.5 * (2**(attempt - 1)), 30.0].min
end

#build_connection ⇒ Object (protected) 



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# File 'lib/parse/embeddings/local_http.rb', line 234

def build_connection
  headers = {
    "Content-Type" => "application/json",
    "Accept" => "application/json",
    "User-Agent" => "parse-stack-embeddings/#{user_agent_version}",
  }
  headers["Authorization"] = "Bearer #{@api_key}" if @api_key

  faraday_opts = { url: @base_url, headers: headers }
  faraday_opts[:proxy] = nil unless @allow_faraday_proxy

  conn = Faraday.new(**faraday_opts) do |f|
    f.options.timeout = @timeout
    f.options.open_timeout = @open_timeout
    f.adapter Faraday.default_adapter
  end
  conn.proxy = nil if !@allow_faraday_proxy && conn.respond_to?(:proxy=)
  conn
end

#dimensions ⇒ Object 



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# File 'lib/parse/embeddings/local_http.rb', line 167

def dimensions
  @dimensions
end

#embed_batch_size ⇒ Object 



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# File 'lib/parse/embeddings/local_http.rb', line 175

def embed_batch_size
  @embed_batch_size
end

#embed_text(strings, input_type: :search_document) ⇒ Array<Array<Float>>

Returns vectors aligned 1:1 with strings.

Parameters:

  • strings (Array<String>) —

    inputs.

  • input_type (Symbol) (defaults to: :search_document) —

    accepted for forward compatibility, ignored at the wire level.

Returns:

  • (Array<Array<Float>>) —

    vectors aligned 1:1 with strings.



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# File 'lib/parse/embeddings/local_http.rb', line 196

def embed_text(strings, input_type: :search_document)
  unless strings.is_a?(Array)
    raise ArgumentError,
          "Parse::Embeddings::LocalHTTP#embed_text expects Array<String> (got #{strings.class})."
  end
  return [] if strings.empty?
  strings.each_with_index do |s, i|
    unless s.is_a?(String)
      raise ArgumentError,
            "Parse::Embeddings::LocalHTTP#embed_text strings[#{i}] is not a String (#{s.class})."
    end
    if s.empty?
      raise ArgumentError,
            "Parse::Embeddings::LocalHTTP#embed_text strings[#{i}] is empty; local runners typically reject empty inputs."
    end
  end

  body = { input: strings, model: @model }

  instrument_embed(strings.length, input_type) do |emit_payload|
    payload = post_embeddings(body)
    # Local runners may or may not include `usage`. When present,
    # forward total_tokens to the AS::N payload.
    if payload.is_a?(Hash) && payload["usage"].is_a?(Hash)
      tt = payload["usage"]["total_tokens"]
      emit_payload[:total_tokens] = tt if tt.is_a?(Integer) && tt >= 0
    end
    vectors = extract_vectors!(payload, strings.length)
    validate_response!(strings.length, vectors)
  end
end

#extract_vectors!(payload, input_count) ⇒ Object (protected)

Accept the OpenAI-compatible shape. Some local runners omit index or return data in request order without it; tolerate both forms by falling back to positional alignment when the field is missing across the entire response.



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# File 'lib/parse/embeddings/local_http.rb', line 315

def extract_vectors!(payload, input_count)
  unless payload.is_a?(Hash)
    raise InvalidResponseError,
          "Parse::Embeddings::LocalHTTP: response body is not a JSON object."
  end
  data = payload["data"]
  unless data.is_a?(Array)
    raise InvalidResponseError,
          "Parse::Embeddings::LocalHTTP: response.data is not an Array."
  end
  if data.length != input_count
    raise InvalidResponseError,
          "Parse::Embeddings::LocalHTTP: response.data.length #{data.length} != input count #{input_count}."
  end
  all_have_index = data.all? { |e| e.is_a?(Hash) && e["index"].is_a?(Integer) }
  if all_have_index
    sorted = data.map do |entry|
      idx = entry["index"]
      unless idx >= 0 && idx < input_count
        raise InvalidResponseError,
              "Parse::Embeddings::LocalHTTP: response.data entry index #{idx} out of range."
      end
      [idx, entry["embedding"]]
    end
    if sorted.map(&:first).uniq.length != sorted.length
      raise InvalidResponseError,
            "Parse::Embeddings::LocalHTTP: duplicate index in response.data."
    end
    sorted.sort_by(&:first).map(&:last)
  else
    data.each_with_index.map do |entry, i|
      unless entry.is_a?(Hash)
        raise InvalidResponseError,
              "Parse::Embeddings::LocalHTTP: response.data[#{i}] is not a JSON object."
      end
      entry["embedding"]
    end
  end
end

#inspect_attrs ⇒ Object 



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# File 'lib/parse/embeddings/local_http.rb', line 228

def inspect_attrs
  super.merge(base: safe_base_host, retries: @max_retries)
end

#model_name ⇒ Object 



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# File 'lib/parse/embeddings/local_http.rb', line 171

def model_name
  @model
end

#normalize? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/parse/embeddings/local_http.rb', line 179

def normalize?
  @normalize
end

#parse_json_body!(body) ⇒ Object (protected) 



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# File 'lib/parse/embeddings/local_http.rb', line 298

def parse_json_body!(body)
  s = body.to_s
  if s.bytesize > MAX_RESPONSE_BYTES
    raise InvalidResponseError,
          "Parse::Embeddings::LocalHTTP: response body exceeds #{MAX_RESPONSE_BYTES} bytes " \
          "(#{s.bytesize}). Refusing to parse."
  end
  JSON.parse(s, max_nesting: 32)
rescue JSON::ParserError => e
  raise InvalidResponseError,
        "Parse::Embeddings::LocalHTTP: response is not valid JSON (#{e.message})."
end

#post_embeddings(body) ⇒ Object (protected) 



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# File 'lib/parse/embeddings/local_http.rb', line 254

def post_embeddings(body)
  attempts = 0
  loop do
    attempts += 1
    begin
      response = @connection.post("embeddings") do |req|
        req.body = body.to_json
      end
    rescue Faraday::TimeoutError, Faraday::ConnectionFailed => e
      if attempts > @max_retries
        raise TransientError, "Parse::Embeddings::LocalHTTP: #{e.class} after #{attempts} attempt(s)."
      end
      sleep(backoff_seconds(attempts))
      next
    end

    status = response.status
    return parse_json_body!(response.body) if status >= 200 && status < 300

    if status == 401
      raise AuthenticationError,
            "Parse::Embeddings::LocalHTTP: 401 Unauthorized — check api_key."
    end
    if status == 429
      if attempts > @max_retries
        raise RateLimitError,
              "Parse::Embeddings::LocalHTTP: 429 rate limited after #{attempts} attempt(s)."
      end
      sleep(retry_after_seconds(response) || backoff_seconds(attempts))
      next
    end
    if status >= 500
      if attempts > @max_retries
        raise TransientError,
              "Parse::Embeddings::LocalHTTP: #{status} after #{attempts} attempt(s)."
      end
      sleep(backoff_seconds(attempts))
      next
    end
    raise BadRequestError,
          "Parse::Embeddings::LocalHTTP: #{status} from POST /embeddings."
  end
end

#retry_after_seconds(response) ⇒ Object (protected) 



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# File 'lib/parse/embeddings/local_http.rb', line 359

def retry_after_seconds(response)
  ra = response.respond_to?(:headers) ? response.headers["retry-after"] || response.headers["Retry-After"] : nil
  return nil unless ra
  v = ra.to_f
  v.positive? ? [v, 60.0].min : nil
end

#supports_input_type? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/parse/embeddings/local_http.rb', line 183

def supports_input_type?
  # The OpenAI-compatible local runners do not asymmetrize. Some
  # models (bge-*) have a documented query prefix, but the local
  # server itself doesn't expose `input_type:` — callers wrap the
  # query text instead. We accept the kwarg for cache-key stability
  # but drop it at the wire level.
  false
end