Configuration
Just like any other Akka module, Akka HTTP is configured via Typesafe Config. Usually this means that you provide an application.conf which contains all the application-specific settings that differ from the default ones provided by the reference configuration files from the individual Akka modules.
These are the relevant default configuration values for the Akka HTTP modules.
- akka-http-core
-
source
######################################## # akka-http-core Reference Config File # ######################################## # This is the reference config file that contains all the default settings. # Make your edits/overrides in your application.conf. # Akka HTTP version, checked against the runtime version of Akka HTTP. # Loaded from generated conf file. include "akka-http-version" akka.http { server { # The default value of the `Server` header to produce if no # explicit `Server`-header was included in a response. # If this value is the empty string and no header was included in # the request, no `Server` header will be rendered at all. server-header = akka-http/${akka.http.version} # "PREVIEW" features that are not yet fully production ready. # These flags can change or be removed between patch releases. preview { # Deprecated, use 'akka.http.server.enable-http2' instead enable-http2 = off } # If this setting is enabled `Http().newServerAt(...).bind` and `bindSync` # will be enabled to use HTTP/2. # # `Http().newServerAt(...).bindFlow` and `connectionSource()` are not supported. # # Default is false enable-http2 = false # The time after which an idle connection will be automatically closed. # Set to `infinite` to completely disable idle connection timeouts. idle-timeout = 60 s # Defines the default time period within which the application has to # produce an HttpResponse for any given HttpRequest it received. # The timeout begins to run when the *end* of the request has been # received, so even potentially long uploads can have a short timeout. # Set to `infinite` to completely disable request timeout checking. # # Make sure this timeout is smaller than the idle-timeout, otherwise, # the idle-timeout will kick in first and reset the TCP connection # without a response. # # If this setting is not `off` the HTTP server layer attaches a # `Timeout-Access` header to the request, which enables programmatic # customization of the timeout period and timeout response for each # request individually. request-timeout = 20 s # The time period within which the TCP binding process must be completed. bind-timeout = 1s # Default port to bind HTTP server to when no port was explicitly given. default-http-port = 80 # Default port to bind HTTPS server to when no port was explicitly given. default-https-port = 443 # The time period the HTTP server implementation will keep a connection open after # all data has been delivered to the network layer. This setting is similar to the SO_LINGER socket option # but does not only include the OS-level socket but also covers the Akka IO / Akka Streams network stack. # The setting is an extra precaution that prevents clients from keeping open a connection that is # already considered completed from the server side. # # If the network level buffers (including the Akka Stream / Akka IO networking stack buffers) # contains more data than can be transferred to the client in the given time when the server-side considers # to be finished with this connection, the client may encounter a connection reset. # # Set to 'infinite' to disable automatic connection closure (which will risk to leak connections). linger-timeout = 1 min # The maximum number of concurrently accepted connections when binding a server using # `Http().newServerAt().bindXYZ()` methods. # # This setting doesn't apply to the `Http().bind` method which will still # deliver an unlimited backpressured stream of incoming connections. # # Note, that this setting limits the number of the connections on a best-effort basis. # It does *not* strictly guarantee that the number of established TCP connections will never # exceed the limit (but it will be approximately correct) because connection termination happens # asynchronously. It also does *not* guarantee that the number of concurrently active handler # flow materializations will never exceed the limit for the reason that it is impossible to reliably # detect when a materialization has ended. max-connections = 1024 # The maximum number of requests that are accepted (and dispatched to # the application) on one single connection before the first request # has to be completed. # Incoming requests that would cause the pipelining limit to be exceeded # are not read from the connections socket so as to build up "back-pressure" # to the client via TCP flow control. # A setting of 1 disables HTTP pipelining, since only one request per # connection can be "open" (i.e. being processed by the application) at any # time. Set to higher values to enable HTTP pipelining. # This value must be > 0 and <= 1024. pipelining-limit = 1 # Enables/disables the addition of a `Remote-Address` header # holding the clients (remote) IP address. # Deprecated since 10.2.0: please use `remote-address-attribute` instead. remote-address-header = off # Enables/disables the addition of a remote-address attribute in HttpRequest # holding the clients (remote) IP address. This is preferred over `remote-address-header` # because it cannot be confused with a real header. remote-address-attribute = off # Enables/disables the addition of a `Raw-Request-URI` header holding the # original raw request URI as the client has sent it. raw-request-uri-header = off # Enables/disables automatic handling of HEAD requests. # If this setting is enabled the server dispatches HEAD requests as GET # requests to the application and automatically strips off all message # bodies from outgoing responses. # Note that, even when this setting is off the server will never send # out message bodies on responses to HEAD requests. transparent-head-requests = off # Enables/disables the returning of more detailed error messages to # the client in the error response. # Should be disabled for browser-facing APIs due to the risk of XSS attacks # and (probably) enabled for internal or non-browser APIs. # Note that akka-http will always produce log messages containing the full # error details. verbose-error-messages = off # The initial size of the buffer to render the response headers in. # Can be used for fine-tuning response rendering performance but probably # doesn't have to be fiddled with in most applications. response-header-size-hint = 512 # The requested maximum length of the queue of incoming connections. # If the server is busy and the backlog is full the OS will start dropping # SYN-packets and connection attempts may fail. Note, that the backlog # size is usually only a maximum size hint for the OS and the OS can # restrict the number further based on global limits. backlog = 100 # If this setting is empty the server only accepts requests that carry a # non-empty `Host` header. Otherwise it responds with `400 Bad Request`. # Set to a non-empty value to be used in lieu of a missing or empty `Host` # header to make the server accept such requests. # Note that the server will never accept HTTP/1.1 request without a `Host` # header, i.e. this setting only affects HTTP/1.1 requests with an empty # `Host` header as well as HTTP/1.0 requests. # Examples: `www.spray.io` or `example.com:8080` default-host-header = "" # Socket options to set for the listening socket. If a setting is left # undefined, it will use whatever the default on the system is. socket-options { so-receive-buffer-size = undefined so-send-buffer-size = undefined so-reuse-address = undefined so-traffic-class = undefined tcp-keep-alive = undefined tcp-oob-inline = undefined tcp-no-delay = undefined } # When graceful termination is enabled and used invoked with a deadline, # after the deadline passes pending requests will be replied to with a "terminating" http response, # instead of delivering those requests to the user-handler. # This response is configurable here using configuration, or via code in case more a sophisticated (e.g. with response entity) # response is needed. # termination-deadline-exceeded-response { # Status code of the "terminating" response to be automatically sent to pending requests once the termination deadline is exceeded. status = 503 # ServiceUnavailable } # Modify to tweak parsing settings on the server-side only. parsing { # no overrides by default, see `akka.http.parsing` for default values # Server-specific parsing settings: # Default maximum content length which should not be exceeded by incoming request entities. # Can be changed at runtime (to a higher or lower value) via the `HttpEntity::withSizeLimit` method. # Note that it is not necessarily a problem to set this to a high value as all stream operations # are always properly backpressured. # Nevertheless you might want to apply some limit in order to prevent a single client from consuming # an excessive amount of server resources. # # Set to `infinite` to completely disable entity length checks. (Even then you can still apply one # programmatically via `withSizeLimit`.) max-content-length = 8m # When a request is so malformed we cannot create a RequestContext out of it, # the regular exception handling does not apply, and a default error handling # is applied that only has access to the parse error and not the actual request. # To customize this error response, set error-handler to the FQCN of an # implementation of akka.http.ParsingErrorHandler error-handler = "akka.http.DefaultParsingErrorHandler$" } # Enables/disables the logging of unencrypted HTTP traffic to and from the HTTP # server for debugging reasons. # # Note: Use with care. Logging of unencrypted data traffic may expose secret data. # # Incoming and outgoing traffic will be logged in hexdump format. To enable logging, # specify the number of bytes to log per chunk of data (the actual chunking depends # on implementation details and networking conditions and should be treated as # arbitrary). # # For logging on the client side, see akka.http.client.log-unencrypted-network-bytes. # # `off` : no log messages are produced # Int : determines how many bytes should be logged per data chunk log-unencrypted-network-bytes = off # Cancellation in the HTTP streams is delayed by this duration to prevent race conditions between cancellation # and stream completion / failure. In most cases, the value chosen here should make no difference because # HTTP streams are loops where completion and failures should propagate immediately and make the handling of # cancellations redundant. # # In most cases, there should be no reason to change this setting. # # Set to 0 to disable the delay. stream-cancellation-delay = 100 millis http2 { # The maximum number of request per connection concurrently dispatched to the request handler. # This limit is enforced as soon as the connection between the peers is established. Enforcing # the limit even before the SETTINGS/SETTINGS_ACK exchange has completed, means # that we will refuse extra streams/requests that were sent by the client right after # the connection was established but before it received our SETTINGS. max-concurrent-streams = 256 # The maximum number of bytes to receive from a request entity in a single chunk. # # The reasoning to limit that amount (instead of delivering all buffered data for a stream) is that # the amount of data in the internal buffers will drive backpressure and flow control on the HTTP/2 level. Bigger # chunks would mean that the user-level entity reader will have to buffer all that data if it cannot read it in one # go. The implementation would not be able to backpressure further data in that case because it does not know about # this user-level buffer. request-entity-chunk-size = 65536 b # The number of request data bytes the HTTP/2 implementation is allowed to buffer internally per connection. Free # space in this buffer is communicated to the peer using HTTP/2 flow-control messages to backpressure data if it # isn't read fast enough. # # When there is no backpressure, this amount will limit the amount of in-flight data. It might need to be increased # for high bandwidth-delay-product connections. # # There is a relation between the `incoming-connection-level-buffer-size` and the `incoming-stream-level-buffer-size`: # If incoming-connection-level-buffer-size < incoming-stream-level-buffer-size * number_of_streams, then # head-of-line blocking is possible between different streams on the same connection. incoming-connection-level-buffer-size = 10 MB # The number of request data bytes the HTTP/2 implementation is allowed to buffer internally per stream. Free space # in this buffer is communicated to the peer using HTTP/2 flow-control messages to backpressure data if it isn't # read fast enough. # # When there is no backpressure, this amount will limit the amount of in-flight data per stream. It might need to # be increased for high bandwidth-delay-product connections. incoming-stream-level-buffer-size = 512kB # For incoming requests, the infrastructure collects at least the given number of bytes before dispatching a HttpRequest. # If all request data is received before or when the threshold is reached, the entity data is dispatched as a strict entity # which allows more efficient processing of the request data without involving streams. # # If the given value is 0, the request is immediately dispatched and always carries a stream of data. # You can use value `1` to create a strict entity if the request contains at most a single data frame, and a streamed # entity otherwise. # # If `min-collect-strict-entity-size > 0` and a request is cancelled (RST_STREAM) before enough data has been collected and the request # is dispatched, then the request is silently discarded. # # To avoid flow control dead-locks, the value must be both smaller or equal than `incoming-stream-level-buffer-size` # and `incoming-connection-level-buffer-size / max-concurrent-streams`. # # Note, that if enabled, requests that expect data (endStream = false on HEADERS) but never received a DATA frame will never be # dispatched. In a regular HTTP context, this is uncommon. It would require that a client would expect data from the server first # before sending any own data. min-collect-strict-entity-size = 0 # The maximum number of outgoing control frames to buffer when the peer does not read from its TCP connection before # backpressuring incoming frames. # # On a healthy HTTP/2 connection this setting should have little effect because control frames are given priority over # data frames and should not be buffered for a long time. # # The limit is necessary to prevent a malicious peer to solicit buffering of outgoing control frames (e.g. by sending PINGs) # without ever reading frames ultimately leading to an out of memory situation. With the limit in place, the implementation # stops reading incoming frames when the number of outgoing control frames has reached the given amount. This way an attacker # isn't able to communicate any further without first freeing space in the TCP window, draining the buffered control frames. # # See CVE-2019-9512 for an example of such an attack. # # Note that only control frames are affected because data frames, in contrast, are covered by the HTTP/2 flow control. outgoing-control-frame-buffer-size = 1024 # Enable verbose debug logging for all ingoing and outgoing frames log-frames = false # When there is no data transmitted in either direction, but there are active streams, send a HTTP/2 ping frame with this initial # delay and subsequent interval to make sure the connection is kept alive, 0s disables sending ping frames. ping-interval = 0s # Fail the connection if a sent ping is not acknowledged within this timeout. # When zero the ping-interval is used, if set the value must be evenly divisible by less than or equal to the ping-interval. ping-timeout = 0s # Limit the number of RSTs a client is allowed to do on one connection, per interval # Protects against rapid reset attacks. If a connection goes over the limit, it is closed with HTTP/2 protocol error ENHANCE_YOUR_CALM max-resets = 400 max-resets-interval = 10s } websocket { # Maximum allowable time between two consecutive elements being received from client. # If no data is received within receive-idle-timeout, the server message handler flow is failed with akka.stream.StreamIdleTimeoutException. # Can be configured together with akka.http.client.server.websocket.periodic-keep-alive-max-idle to catch unexpected # client disconnections (if client supports pong replies) receive-idle-timeout = infinite # Maximum allowable time between two consecutive elements being send to client. # If no data is sent within send-idle-timeout, server message handler flow is failed with akka.stream.StreamIdleTimeoutException. send-idle-timeout = infinite # periodic keep alive may be implemented using by sending Ping frames # upon which the other side is expected to reply with a Pong frame, # or by sending a Pong frame, which serves as unidirectional heartbeat. # Valid values: # ping - default, for bi-directional ping/pong keep-alive heartbeating # pong - for uni-directional pong keep-alive heartbeating # # It is also possible to provide a payload for each heartbeat message, # this setting can be configured programatically by modifying the websocket settings. # See: https://doc.akka.io/docs/akka-http/current/server-side/websocket-support.html periodic-keep-alive-mode = ping # Interval for sending periodic keep-alives # The frame sent will be the one configured in akka.http.server.websocket.periodic-keep-alive-mode # `infinite` by default, or a duration that is the max idle interval after which an keep-alive frame should be sent # The value `infinite` means that *no* keep-alive heartbeat will be sent, as: "the allowed idle time is infinite" periodic-keep-alive-max-idle = infinite # Enable verbose debug logging for all ingoing and outgoing frames log-frames = false } } #client-settings client { # The default value of the `User-Agent` header to produce if no # explicit `User-Agent`-header was included in a request. # If this value is the empty string and no header was included in # the request, no `User-Agent` header will be rendered at all. user-agent-header = akka-http/${akka.http.version} # The time period within which the TCP connecting process must be completed. connecting-timeout = 10s # The time after which an idle connection will be automatically closed. # Set to `infinite` to completely disable idle timeouts. idle-timeout = 60 s # The initial size of the buffer to render the request headers in. # Can be used for fine-tuning request rendering performance but probably # doesn't have to be fiddled with in most applications. request-header-size-hint = 512 # Socket options to set for the listening socket. If a setting is left # undefined, it will use whatever the default on the system is. socket-options { so-receive-buffer-size = undefined so-send-buffer-size = undefined so-reuse-address = undefined so-traffic-class = undefined tcp-keep-alive = undefined tcp-oob-inline = undefined tcp-no-delay = undefined } # Client https proxy options. When using ClientTransport.httpsProxy() with or without credentials, # host/port must be either passed explicitly or set here. If a host is not set, the proxy will not be used. proxy { https { host = "" port = 443 } } # Modify to tweak parsing settings on the client-side only. parsing { # no overrides by default, see `akka.http.parsing` for default values # Default maximum content length which should not be exceeded by incoming response entities. # Can be changed at runtime (to a higher or lower value) via the `HttpEntity::withSizeLimit` method. # Note that it is not necessarily a problem to set this to a high value as all stream operations # are always properly backpressured. # # On the client-side, this limit is disabled by default because a client controls the requests it runs. # # Set to `infinite` to completely disable entity length checks. (Even then you can still apply one # programmatically via `withSizeLimit`.) max-content-length = infinite } # Enables/disables the logging of unencrypted HTTP traffic to and from the HTTP # client for debugging reasons. # # Note: Use with care. Logging of unencrypted data traffic may expose secret data. # # Incoming and outgoing traffic will be logged in hexdump format. To enable logging, # specify the number of bytes to log per chunk of data (the actual chunking depends # on implementation details and networking conditions and should be treated as # arbitrary). # # For logging on the server side, see akka.http.server.log-unencrypted-network-bytes. # # `off` : no log messages are produced # Int : determines how many bytes should be logged per data chunk log-unencrypted-network-bytes = off #client-settings // FIXME: unify with server-side part (by importing or similar to parsing) http2 { # The maximum number of request per connection concurrently dispatched to the request handler. # This limit is enforced as soon as the connection between the peers is established. Enforcing # the limit even before the SETTINGS/SETTINGS_ACK exchange has completed, means # that we will refuse extra streams/push promises that were sent by the client right after # the connection was established but before it received our SETTINGS. max-concurrent-streams = 256 # The maximum number of bytes to receive from a request entity in a single chunk. # # The reasoning to limit that amount (instead of delivering all buffered data for a stream) is that # the amount of data in the internal buffers will drive backpressure and flow control on the HTTP/2 level. Bigger # chunks would mean that the user-level entity reader will have to buffer all that data if it cannot read it in one # go. The implementation would not be able to backpressure further data in that case because it does not know about # this user-level buffer. request-entity-chunk-size = 65536 b # The number of request data bytes the HTTP/2 implementation is allowed to buffer internally per connection. Free # space in this buffer is communicated to the peer using HTTP/2 flow-control messages to backpressure data if it # isn't read fast enough. # # When there is no backpressure, this amount will limit the amount of in-flight data. It might need to be increased # for high bandwidth-delay-product connections. # # There is a relation between the `incoming-connection-level-buffer-size` and the `incoming-stream-level-buffer-size`: # If incoming-connection-level-buffer-size < incoming-stream-level-buffer-size * number_of_streams, then # head-of-line blocking is possible between different streams on the same connection. incoming-connection-level-buffer-size = 10 MB # The number of request data bytes the HTTP/2 implementation is allowed to buffer internally per stream. Free space # in this buffer is communicated to the peer using HTTP/2 flow-control messages to backpressure data if it isn't # read fast enough. # # When there is no backpressure, this amount will limit the amount of in-flight data per stream. It might need to # be increased for high bandwidth-delay-product connections. incoming-stream-level-buffer-size = 512kB # The maximum number of outgoing control frames to buffer when the peer does not read from its TCP connection before # backpressuring incoming frames. # # On a healthy HTTP/2 connection this setting should have little effect because control frames are given priority over # data frames and should not be buffered for a long time. # # The limit is necessary to prevent a malicious peer to solicit buffering of outgoing control frames (e.g. by sending PINGs) # without ever reading frames ultimately leading to an out of memory situation. With the limit in place, the implementation # stops reading incoming frames when the number of outgoing control frames has reached the given amount. This way an attacker # isn't able to communicate any further without first freeing space in the TCP window, draining the buffered control frames. # # See CVE-2019-9512 for an example of such an attack. # # Note that only control frames are affected because data frames, in contrast, are covered by the HTTP/2 flow control. outgoing-control-frame-buffer-size = 1024 # Enable verbose debug logging for all ingoing and outgoing frames log-frames = false # When there is no data transmitted in either direction, but there are active streams, send a HTTP/2 ping frame with this initial # delay and subsequent interval to make sure the connection is kept alive, 0s disables sending ping frames. ping-interval = 0s # Fail the connection if a sent ping is not acknowledged within this timeout. # When zero the ping-interval is used, if set the value must be evenly divisible by less than or equal to the ping-interval. ping-timeout = 0s # The maximum number of times a connections is attempted # before giving up and returning an error. # Set to zero to retry indefinitely. max-persistent-attempts = 0 # Starting backoff before reconnecting when a persistent HTTP/2 client connection fails # see `akka.http.host-connection-pool.base-connection-backoff` for details on the backoff mechanism. base-connection-backoff = ${akka.http.host-connection-pool.base-connection-backoff} # Max backoff between reconnect attempts when a persistent HTTP/2 client connection fails # see `akka.http.host-connection-pool.max-connection-backoff` for details on the backoff mechanism. max-connection-backoff = ${akka.http.host-connection-pool.max-connection-backoff} # When gracefully closing the HTTP/2 client, await at most `completion-timeout` for in-flight # requests to complete. completion-timeout = 3s } #client-settings websocket { # Maximum allowable time between two consecutive elements being received from server. # If no data is received within receive-idle-timeout, the client flow is failed with akka.stream.StreamIdleTimeoutException. # Can be configured together with akka.http.client.client.websocket.periodic-keep-alive-max-idle to catch unexpected # network disconnections (if server supports pong replies) receive-idle-timeout = infinite # Maximum allowable time between two consecutive elements being send to server. # If no data is sent within send-idle-timeout, the client flow is failed with akka.stream.StreamIdleTimeoutException. send-idle-timeout = infinite # periodic keep alive may be implemented using by sending Ping frames # upon which the other side is expected to reply with a Pong frame, # or by sending a Pong frame, which serves as unidirectional heartbeat. # Valid values: # ping - default, for bi-directional ping/pong keep-alive heartbeating # pong - for uni-directional pong keep-alive heartbeating # # See https://tools.ietf.org/html/rfc6455#section-5.5.2 # and https://tools.ietf.org/html/rfc6455#section-5.5.3 for more information periodic-keep-alive-mode = ping # Interval for sending periodic keep-alives # The frame sent will be the one configured in akka.http.server.websocket.periodic-keep-alive-mode # `infinite` by default, or a duration that is the max idle interval after which an keep-alive frame should be sent periodic-keep-alive-max-idle = infinite # Enable verbose debug logging for all ingoing and outgoing frames log-frames = false } # Cancellation in the HTTP streams is delayed by this duration to prevent race conditions between cancellation # and stream completion / failure. In most cases, the value chosen here should make no difference because # HTTP streams are loops where completion and failures should propagate immediately and make the handling of # cancellations redundant. # # In most cases, there should be no reason to change this setting. # # Set to 0 to disable the delay. stream-cancellation-delay = 100 millis } #client-settings #pool-settings host-connection-pool { # The maximum number of parallel connections that a connection pool to a # single host endpoint is allowed to establish. Must be greater than zero. max-connections = 4 # The minimum number of parallel connections that a pool should keep alive ("hot"). # If the number of connections is falling below the given threshold, new ones are being spawned. # You can use this setting to build a hot pool of "always on" connections. # Default is 0, meaning there might be no active connection at given moment. # Keep in mind that `min-connections` should be smaller than `max-connections` or equal min-connections = 0 # The maximum number of times failed requests are attempted again, # (if the request can be safely retried) before giving up and returning an error. # Set to zero to completely disable request retries. max-retries = 5 # The maximum number of open requests accepted into the pool across all # materializations of any of its client flows. # Protects against (accidentally) overloading a single pool with too many client flow materializations. # Note that with N concurrent materializations the max number of open request in the pool # will never exceed N * max-connections * pipelining-limit. # Must be a power of 2 and > 0! max-open-requests = 32 # The maximum duration for a connection to be kept alive # This amount gets modified by a 10 percent fuzzyness to avoid the simultanous reconnections # defaults to 'infinite' # Note that this is only implemented in the new host connection pool max-connection-lifetime = infinite # Client-side pipelining is not currently supported. See https://github.com/akka/akka-http/issues/32 pipelining-limit = 1 # The minimum duration to backoff new connection attempts after the previous connection attempt failed. # # The pool uses an exponential randomized backoff scheme. After the first failure, the next attempt will only be # tried after a random duration between the base connection backoff and twice the base connection backoff. If that # attempt fails as well, the next attempt will be delayed by twice that amount. The total delay is capped using the # `max-connection-backoff` setting. # # The backoff applies for the complete pool. I.e. after one failed connection attempt, further connection attempts # to that host will backoff for all connections of the pool. After the service recovered, connections will come out # of backoff one by one due to the random extra backoff time. This is to avoid overloading just recently recovered # services with new connections ("thundering herd"). # # Example: base-connection-backoff = 100ms, max-connection-backoff = 10 seconds # - After 1st failure, backoff somewhere between 100ms and 200ms # - After 2nd, between 200ms and 400ms # - After 3rd, between 200ms and 400ms # - After 4th, between 400ms and 800ms # - After 5th, between 800ms and 1600ms # - After 6th, between 1600ms and 3200ms # - After 7th, between 3200ms and 6400ms # - After 8th, between 5000ms and 10 seconds (max capped by max-connection-backoff, min by half of that) # - After 9th, etc., stays between 5000ms and 10 seconds # # This setting only applies to the new pool implementation and is ignored for the legacy one. base-connection-backoff = 100ms # Maximum backoff duration between failed connection attempts. For more information see the above comment for the # `base-connection-backoff` setting. # # This setting only applies to the new pool implementation and is ignored for the legacy one. max-connection-backoff = 2 min # The time after which an idle connection pool (without pending requests) # will automatically terminate itself. Set to `infinite` to completely disable idle timeouts. idle-timeout = 30 s # HTTP connections are commonly used for multiple requests, that is, they are kept alive between requests. The # `akka.http.host-connection-pool.keep-alive-timeout` setting configures how long a pool keeps a connection alive between # requests before it closes the connection (and eventually reestablishes it). # # A common scenario where this setting is useful is to prevent a race-condition inherent in HTTP: in most cases, a server # or reverse-proxy closes a persistent (kept-alive) connection after some time. HTTP does not define a protocol between # client and server to negotiate a graceful teardown of an idle persistent connection. Therefore, it can happen that a server decides to # close a connection at the same time that a client decides to send a new request. In that case, the request will fail to be processed, # but the client cannot determine for which reason the server closed the connection and whether the request was (partly) processed or not. # Such a condition can be observed when a request fails with an `UnexpectedConnectionClosureException` or a `StreamTcpException` stating # "Connection reset by peer". # # To prevent this from happening, you can set the timeout to a lower value than the server-side keep-alive timeout # (which you either have to know or find out experimentally). # # Set to `infinite` to allow the connection to remain open indefinitely (or be closed by the more general `idle-timeout`). keep-alive-timeout = infinite # The pool implementation will fail a connection early and clear the slot if a response entity was not # subscribed during the given time period after the response was dispatched. In busy systems the timeout might be # too tight if a response is not picked up quick enough after it was dispatched by the pool. response-entity-subscription-timeout = 1.second # Modify this section to tweak client settings only for host connection pools APIs like `Http().superPool` or # `Http().singleRequest`. client = { # no overrides by default, see `akka.http.client` for default values } #per-host-overrides # Allows overriding settings per host. The setting must be a list in which each entry # is an object with a `host-pattern` entry that specifies for which hosts the overrides # should take effect. All other entries have the same syntax as entries in the # `host-connection-pool` section. # # The `host-pattern` can have these forms: # * `regex:<pattern>`: the host name is matched against the regular expression pattern # * `glob:<glob-pattern>` or just `<glob-pattern>`: the host is matched against the given # pattern. In the pattern the wildcard `*` stands for zero or more characters and `?` # for any single character # # In both cases, a pattern that matches `*.` at the beginning, i.e. every subdomain, # is expanded to also cover the domain itself (without the leading dot). # # If patterns from multiple entries in the list are matched, only settings from the # first entry found are applied. # # Example: # # per-host-override = [ # { # host-pattern = "doc.akka.io" # # Use the same entries as in the `host-connection-pool` section # max-connections = 10 # }, # { # # `*.akka.io` matches all subdomains like `repo.akka.io` but also `akka.io` itself. # # `doc.akka.io` is already covered by a previous entry, so these settings here # # will not apply to `doc.akka.io`. # host-pattern = "*.akka.io" # max-connections = 11 # } # ] per-host-override = [] #per-host-overrides } #pool-settings # Modify to tweak default parsing settings. # # IMPORTANT: # Please note that this sections settings can be overridden by the corresponding settings in: # `akka.http.server.parsing`, `akka.http.client.parsing` or `akka.http.host-connection-pool.client.parsing`. parsing { # The limits for the various parts of the HTTP message parser. max-uri-length = 2k max-method-length = 16 max-response-reason-length = 64 max-header-name-length = 64 max-header-value-length = 8k max-header-count = 64 max-chunk-ext-length = 256 max-chunk-size = 1m # HTTP comments (as e.g. prominently used in User-Agent headers) can be nested. To avoid too deep nesting # and the associated parsing and storage cost, the depth of nested comments is limited to the given value. max-comment-parsing-depth = 5 # The maximum number of bytes to allow when reading the entire entity into memory with `toStrict` # (which is used by the `toStrictEntity` and `extractStrictEntity` directives) max-to-strict-bytes = 8m # Sets the strictness mode for parsing request target URIs. # The following values are defined: # # `strict`: RFC3986-compliant URIs are required, # a 400 response is triggered on violations # # `relaxed`: all visible 7-Bit ASCII chars are allowed # uri-parsing-mode = strict # Sets the parsing mode for parsing cookies. # The following value are defined: # # `rfc6265`: Only RFC6265-compliant cookies are parsed. Surrounding double-quotes are accepted and # automatically removed. Non-compliant cookies are silently discarded. # `raw`: Raw parsing allows any non-control character but ';' to appear in a cookie value. There's no further # post-processing applied, so that the resulting value string may contain any number of whitespace, unicode, # double quotes, or '=' characters at any position. # The rules for parsing the cookie name are the same ones from RFC 6265. # cookie-parsing-mode = rfc6265 # Enables/disables the logging of warning messages in case an incoming # message (request or response) contains an HTTP header which cannot be # parsed into its high-level model class due to incompatible syntax. # Note that, independently of this settings, akka-http will accept messages # with such headers as long as the message as a whole would still be legal # under the HTTP specification even without this header. # If a header cannot be parsed into a high-level model instance it will be # provided as a `RawHeader`. # If logging is enabled it is performed with the configured # `error-logging-verbosity`. illegal-header-warnings = on # Sets the list of headers for which illegal values will *not* cause warning logs to be emitted; # # Adding a header name to this setting list disables the logging of warning messages in case an incoming　message # contains an HTTP header which cannot be　parsed into its high-level model class due to incompatible syntax. ignore-illegal-header-for = [] # Parse headers into typed model classes in the Akka Http core layer. # # If set to `off`, only essential headers will be parsed into their model classes. All other ones will be provided # as instances of `RawHeader`. Currently, `Connection`, `Host`, and `Expect` headers will still be provided in their # typed model. The full list of headers still provided as modeled instances can be found in the source code of # `akka.http.impl.engine.parsing.HttpHeaderParser.alwaysParsedHeaders`. Note that (regardless of this setting) # some headers like `Content-Type` are treated specially and will never be provided in the list of headers. modeled-header-parsing = on # Configures the verbosity with which message (request or response) parsing # errors are written to the application log. # # Supported settings: # `off` : no log messages are produced # `simple`: a condensed single-line message is logged # `full` : the full error details (potentially spanning several lines) are logged error-logging-verbosity = full # Configures the processing mode when encountering illegal characters in # header name of response. # # Supported mode: # `error` : default mode, reject the request # `warn` : ignore the illegal characters in response header value and log a warning message # `ignore` : just ignore the illegal characters in response header value illegal-response-header-name-processing-mode = error # Configures the processing mode when encountering illegal characters in # header value of response. # # Supported mode: # `error` : default mode, throw an ParsingException and terminate the processing # `warn` : ignore the illegal characters in response header value and log a warning message # `ignore` : just ignore the illegal characters in response header value illegal-response-header-value-processing-mode = error # Configures the processing mode when encountering conflicting `Content-Type` headers. # # Supported mode: # `error` : default mode, throw an ParsingException and terminate the processing # `first` : use the value of the first `Content-Type` header and add all subsequent `Content-Type` headers to the headers list # `last` : use the value of the last `Content-Type` header and add all preceding `Content-Type` headers to the headers list # `no-content-type` : use `ContentTypes.NoContentType` and add all `Content-Type` headers to the headers list conflicting-content-type-header-processing-mode = error # limits for the number of different values per header type that the # header cache will hold header-cache { default = 12 Content-MD5 = 0 Date = 0 If-Match = 0 If-Modified-Since = 0 If-None-Match = 0 If-Range = 0 If-Unmodified-Since = 0 User-Agent = 32 } # Enables/disables inclusion of an Tls-Session-Info header in parsed # messages over Tls transports (i.e., HttpRequest on server side and # HttpResponse on client side). tls-session-info-header = off # Enables/disables inclusion of an SslSession attribute in parsed # messages over Tls transports (i.e., HttpRequest on server side and # HttpResponse on client side). ssl-session-attribute = off } } - akka-http
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################################### # akka-http Reference Config File # ################################### # This is the reference config file that contains all the default settings. # Make your edits/overrides in your application.conf. akka.http { routing { # Enables/disables the returning of more detailed error messages to the # client in the error response # Should be disabled for browser-facing APIs due to the risk of XSS attacks # and (probably) enabled for internal or non-browser APIs # (Note that akka-http will always produce log messages containing the full error details) verbose-error-messages = off # Enables/disables ETag and `If-Modified-Since` support for FileAndResourceDirectives file-get-conditional = on # Enables/disables the rendering of the "rendered by" footer in directory listings render-vanity-footer = yes # The maximum size between two requested ranges. Ranges with less space in between will be coalesced. # # When multiple ranges are requested, a server may coalesce any of the ranges that overlap or that are separated # by a gap that is smaller than the overhead of sending multiple parts, regardless of the order in which the # corresponding byte-range-spec appeared in the received Range header field. Since the typical overhead between # parts of a multipart/byteranges payload is around 80 bytes, depending on the selected representation's # media type and the chosen boundary parameter length, it can be less efficient to transfer many small # disjoint parts than it is to transfer the entire selected representation. range-coalescing-threshold = 80 # The maximum number of allowed ranges per request. # Requests with more ranges will be rejected due to DOS suspicion. range-count-limit = 16 # The maximum number of bytes per ByteString a decoding directive will produce # for an entity data stream. decode-max-bytes-per-chunk = 1m # Maximum content length after applying a decoding directive. When the directive # decompresses, for example, an entity compressed with gzip, the resulting stream can be much # larger than the max-content-length. Like with max-content-length, this is not necessarilly a # problem when consuming the entity in a streaming fashion, but does risk high memory use # when the entity is made strict or marshalled into an in-memory object. # This limit (like max-content-length) can be overridden on a case-by-case basis using the # withSizeLimit directive. decode-max-size = 8m } # server-sent events sse { # The maximum size for parsing server-sent events. max-event-size = 8192 # The maximum size for parsing lines of a server-sent event. max-line-size = 4096 # Empty events are used by the akka-http SSE infrastructure for heartbeats. Received heartbeats are ignored by default # and not delivered in the user stream. # # This setting can be enabled to pass those empty events to the application for explicit handling. emit-empty-events = off } # Configuration for the cors directive, does not apply unless the directive is used #cors cors { # Allow generic requests, that are outside the scope of the specification, for example lacking # an `Origin` header to pass through the directive. # # When false strict CORS filtering is applied and any invalid request will be rejected. allow-generic-http-requests = on # If enabled, the header `Access-Control-Allow-Credentials` # is included in the response, indicating that the actual request can include user credentials. # Examples of user credentials are: cookies, HTTP authentication or client-side certificates. allow-credentials = on # List of origins that the CORS filter must allow. # # Can also be set to a single `*` to allow access to the resource from any origin. # # Controls the content of the `Access-Control-Allow-Origin` response header: if parameter is `*` and # credentials are not allowed, a `*` is returned in `Access-Control-Allow-Origin`. Otherwise, the origins given in the # `Origin` request header are echoed. # # Hostname starting with `*.` will match any sub-domain. The scheme and the port are always strictly matched. # # The actual or preflight request is rejected if any of the origins from the request is not allowed.. allowed-origins = ["*"] # Set of request headers that are allowed when making an actual request. # # Controls the content of the `Access-Control-Allow-Headers` header in a preflight response: If set to a single `*`, # the headers from `Access-Control-Request-Headers` are echoed. Otherwise specified list of header names is returned # as part of the header. allowed-headers = ["*"] # List of methods allowed when making an actual request. The listed headers are returned as part of the # `Access-Control-Allow-Methods` preflight response header. # # The preflight request will be rejected if the `Access-Control-Request-Method` header's method is not part of the # list. allowed-methods = ["GET", "POST", "HEAD", "OPTIONS"] # Set of headers (other than simple response headers) that browsers are allowed to access. If not empty, the listed # headers are returned as part of the `Access-Control-Expose-Headers` header in responses. exposed-headers = [] # The time the browser is allowed to cache the results of a preflight request. This value is # returned as part of the `Access-Control-Max-Age` preflight response header. If `scala.concurrent.duration.Duration.Zero`, # the header is not added to the preflight response. max-age = 1800 seconds } #cors } - akka-http-caching
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########################################### # akka-http-caching Reference Config File # ########################################### # This is the reference config file that contains all the default settings. # Make your edits/overrides in your application.conf. akka.http.caching { # Default configuration values for LfuCache lfu-cache { # Maximum number of entries the cache may store. # After the maximum capacity is reached the cache evicts entries that are # less likely to be used again. For example, the cache may evict an entry # because it hasn't been used recently or very often. max-capacity = 512 # Minimum total size for the internal data structures. initial-capacity = 16 # Upper limit to the time period an entry is allowed to remain in the cache. # Set to 'infinite' to disable eviction based on time of write (create or update). time-to-live = infinite # Maximum time period an entry is allowed to remain in the cache after last access. # Access time is reset by all cache read and write operations. # Set to 'infinite' to disable time-based expiration. time-to-idle = infinite } }
The other Akka HTTP modules do not offer any configuration via Typesafe Config.