# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright contributors to the vLLM project

import hashlib
from functools import cached_property
from typing import Any, Literal, cast

from pydantic.dataclasses import dataclass

from vllm import version
from vllm.config.utils import config

DetailedTraceModules = Literal["model", "worker", "all"]


@config
@dataclass
class ObservabilityConfig:
    """Configuration for observability - metrics and tracing."""

    show_hidden_metrics_for_version: str | None = None
    """Enable deprecated Prometheus metrics that have been hidden since the
    specified version. For example, if a previously deprecated metric has been
    hidden since the v0.7.0 release, you use
    `--show-hidden-metrics-for-version=0.7` as a temporary escape hatch while
    you migrate to new metrics. The metric is likely to be removed completely
    in an upcoming release."""

    @cached_property
    def show_hidden_metrics(self) -> bool:
        """Check if the hidden metrics should be shown."""
        if self.show_hidden_metrics_for_version is None:
            return False
        return version._prev_minor_version_was(self.show_hidden_metrics_for_version)

    otlp_traces_endpoint: str | None = None
    """Target URL to which OpenTelemetry traces will be sent."""

    collect_detailed_traces: list[DetailedTraceModules] | None = None
    """It makes sense to set this only if `--otlp-traces-endpoint` is set. If
    set, it will collect detailed traces for the specified modules. This
    involves use of possibly costly and or blocking operations and hence might
    have a performance impact.

    Note that collecting detailed timing information for each request can be
    expensive."""

    @cached_property
    def collect_model_forward_time(self) -> bool:
        """Whether to collect model forward time for the request."""
        return self.collect_detailed_traces is not None and (
            "model" in self.collect_detailed_traces
            or "all" in self.collect_detailed_traces
        )

    @cached_property
    def collect_model_execute_time(self) -> bool:
        """Whether to collect model execute time for the request."""
        return self.collect_detailed_traces is not None and (
            "worker" in self.collect_detailed_traces
            or "all" in self.collect_detailed_traces
        )

    def compute_hash(self) -> str:
        """
        WARNING: Whenever a new field is added to this config,
        ensure that it is included in the factors list if
        it affects the computation graph.

        Provide a hash that uniquely identifies all the configs
        that affect the structure of the computation
        graph from input ids/embeddings to the final hidden states,
        excluding anything before input ids/embeddings and after
        the final hidden states.
        """
        # no factors to consider.
        # this config will not affect the computation graph.
        factors: list[Any] = []
        hash_str = hashlib.md5(str(factors).encode(), usedforsecurity=False).hexdigest()
        return hash_str

    def __post_init__(self):
        if (
            self.collect_detailed_traces is not None
            and len(self.collect_detailed_traces) == 1
            and "," in self.collect_detailed_traces[0]
        ):
            self._parse_collect_detailed_traces()

        from vllm.tracing import is_otel_available, otel_import_error_traceback

        if not is_otel_available() and self.otlp_traces_endpoint is not None:
            raise ValueError(
                "OpenTelemetry is not available. Unable to configure "
                "'otlp_traces_endpoint'. Ensure OpenTelemetry packages are "
                f"installed. Original error:\n{otel_import_error_traceback}"
            )

    def _parse_collect_detailed_traces(self):
        assert isinstance(self.collect_detailed_traces, list)
        self.collect_detailed_traces = cast(
            list[DetailedTraceModules], self.collect_detailed_traces[0].split(",")
        )
