Environment variable reference#

conda-presto reads these settings when its configuration module is imported. The scope column identifies the operations affected by each setting.

Solve settings#

These settings affect conda presto and HTTP operations. Ordinary solves use inline specs or non-workspace input files. Workspace solves compose requirements from manifest environments and targets.

Variable	Default	Scope	Purpose
`CONDA_PRESTO_CHANNELS`	`conda-forge`	Ordinary CLI and HTTP	HTTP fallback when no request or input file supplies channels. CLI fallback when conda’s effective channels are empty or only `defaults` and no file supplies channels. Also used for server startup warmup. Workspace channels come from the manifest.
`CONDA_PRESTO_WORKERS`	`min(4, cpu_count)`	Ordinary multi-platform solves	Process-pool size for platforms within one request. Workspace targets run sequentially.
`CONDA_PRESTO_MAX_INDEX_CACHE_ENTRIES`	`128`	Ordinary solve processes	Maximum retained rattler indexes in Presto’s direct solver path. Set to `0` to disable index retention.
`CONDA_PRESTO_GLIBC_VERSION`	`2.17`	Linux targets	Default virtual `__glibc` version.
`CONDA_PRESTO_LINUX_VERSION`	`5.15`	Linux targets	Default virtual `__linux` version.
`CONDA_PRESTO_OSX_VERSION`	`11.0`	macOS targets	Default virtual `__osx` version.
`CONDA_PRESTO_WIN_VERSION`	`0`	Windows targets	Default virtual `__win` version.

Ordinary CLI and HTTP solves apply these target-model defaults for each requested Linux, macOS, or Windows target, including conda’s startup subdir. The resulting effective records can also include other virtual-package plugin detections or overrides, such as CUDA or architecture records. The public result-cache identity captures those effective records per requested platform.

Workspace solves and lock updates apply manifest system requirements over these OS-version defaults. For overridable virtual-package plugins, they replace ambient CONDA_OVERRIDE_* values and suppress host detections for undeclared requirements. Workspace cache identity records the effective virtual packages for each selected logical target.

HTTP server settings#

Variable	Default	Purpose
`CONDA_PRESTO_PLATFORMS`	`linux-64,osx-arm64,osx-64`	Platforms whose configured channels are warmed before readiness. This is not the default platform list for a request.
`CONDA_PRESTO_ALLOWED_CHANNELS`	value of `CONDA_PRESTO_CHANNELS`	Accepted HTTP request channels after exact resolved-URL comparison. `*` permits HTTP and HTTPS channels but not local file URLs.
`CONDA_PRESTO_CONCURRENCY`	`4`	Maximum simultaneous foreground solve requests. Docker sets `1`.
`CONDA_PRESTO_MAX_BODY_BYTES`	`1048576`	Maximum HTTP request body. Excess returns HTTP 413.
`CONDA_PRESTO_MAX_SPECS`	`200`	Maximum specs in one request.
`CONDA_PRESTO_MAX_CHANNELS`	`8`	Maximum channels in one request.
`CONDA_PRESTO_MAX_PLATFORMS`	`8`	Maximum platforms in an ordinary request, or selected environment/target pairs in a workspace request.
`CONDA_PRESTO_SOLVE_TIMEOUT_S`	`60`	Deadline for HTTP solves and CLI `--update`, including its input parsing and worker startup. Non-abandoned HTTP cache-state inspection can extend observed request duration.
`CONDA_PRESTO_PARSE_TIMEOUT_S`	`10`	Input-parse timeout for HTTP uploads and CLI `--parse`, `--export`, `--validate` and `--update`. CLI updates also remain subject to their shared solve deadline.
`CONDA_PRESTO_HOST`	`127.0.0.1`	Default for the `--host` server flag. The Docker command fixes `0.0.0.0`.
`CONDA_PRESTO_PORT`	`8000`	Default for the `--port` server flag. The Docker health check follows this setting.
`CONDA_PRESTO_PERSISTENT_WORKER`	`false`	Route HTTP solves through one worker that retains loaded repodata and indexes. Set by Docker.
`CONDA_PRESTO_RATE_LIMIT`	`300`	Requests per minute per client IP. Set to `0` to disable.
`CONDA_PRESTO_CORS_ORIGINS`	unset	Comma-separated browser origins. CORS middleware is absent when unset.
`CONDA_PRESTO_LOG_LEVEL`	`INFO`	Application logger level: `DEBUG`, `INFO`, `WARNING`, or `ERROR`.

Request-cap violations return HTTP 400 unless the body limit applies.

Result cache settings#

These settings apply to HTTP applications. One-shot CLI output does not use the HTTP result cache.

Variable	Default	Purpose
`CONDA_PRESTO_RESULT_CACHE_SIZE`	`256`	In-process entry limit for resolve responses.
`CONDA_PRESTO_RESULT_CACHE_MAX_MEMORY_MB`	`64`	Encoded payload limit in MiB. Set to `0` to remove the byte cap.
`CONDA_PRESTO_RESULT_CACHE_BACKEND`	automatic	`memory`, `file`, or `redis`.
`CONDA_PRESTO_RESULT_CACHE_DIR`	unset	Directory required by the file backend. Selecting no backend but setting this value selects file storage.
`CONDA_PRESTO_RESULT_CACHE_REDIS_URL`	unset	Redis URL. Selecting Redis without a URL uses `redis://localhost:6379/0`. Setting this value selects Redis when no backend is explicit.
`CONDA_PRESTO_RESULT_CACHE_REDIS_NAMESPACE`	`conda-presto`	Redis key namespace.

Negative entry or memory limits are rejected. File storage without a directory and unknown backend names are also rejected. See Cache reference for key and retention behavior.

Sigstore settings#

Variable	Default	Purpose
`CONDA_PRESTO_SIGSTORE_SIGNING_ENABLED`	`false`	Enable signing service-produced artifacts with noninteractive credentials and a configured trust choice.
`CONDA_PRESTO_SIGSTORE_ALLOW_PUBLIC_SIGNING`	`false`	Explicitly permit use of the public signing service.
`CONDA_PRESTO_SIGSTORE_TRUST_CONFIG`	unset	Path to an operator-provided Sigstore `ClientTrustConfig` JSON file. Signing requires both its trusted root and signing configuration. A path alone does not enable signing.
`CONDA_PRESTO_SIGSTORE_OFFLINE`	`false`	Select offline verification using the configured trust material.

Standard installations include SBOM generation, signing and verification support. Signing is disabled by default. Capability discovery reports configuration and provider availability, not a guarantee that signing credentials are currently usable. See Configuration for the conda-sigstore requirements and Sign and verify a retained output for supported unattended credentials and request examples.

Pixi activation settings#

The repository’s Pixi environments set these conda variables for solve-only workloads:

Variable	Value	Effect
`CONDA_SOLVER`	`rattler`	Select rattler in conda context before conda-presto applies its direct-engine requirement.
`CONDA_CHANNEL_PRIORITY`	`strict`	Prefer higher-priority channels.
`CONDA_NO_LOCK`	`true`	Disable conda filesystem locking in the shared Pixi activation. The Docker server overrides this to `false`.
`CONDA_UNSATISFIABLE_HINTS`	`false`	Disable conda’s additional unsatisfiable hint generation.
`CONDA_NUMBER_CHANNEL_NOTICES`	`0`	Suppress channel notices.
`CONDA_AGGRESSIVE_UPDATE_PACKAGES`	empty	Disable forced aggressive updates.
`CONDA_LOCAL_REPODATA_TTL`	`300`	Reuse local repodata under conda’s effective cache policy.
`CONDA_JSON`	`true`	Suppress progress-oriented conda output.

The Docker server applies CONDA_NO_LOCK=false after its Pixi shell hook because persistent workers share conda’s package cache.