Mongo proxy

• MongoDB architecture overview

• v2 API reference

• This filter should be configured with the name envoy.mongo_proxy.

Fault injection

The Mongo proxy filter supports fault injection. See the v2 API reference for how to configure.

Statistics

Every configured MongoDB proxy filter has statistics rooted at mongo.. with the following statistics:

Scatter gets

Envoy defines a scatter get as any query that does not use an _id field as a query parameter. Envoy looks in both the top level document as well as within a $query field for _id.

Multi gets

Envoy defines a multi get as any query that does use an _id field as a query parameter, but where _id is not a scalar value (i.e., a document or an array). Envoy looks in both the top level document as well as within a $query field for _id.

$comment parsing

If a query has a top level $comment field (typically in addition to a $query field), Envoy will parse it as JSON and look for the following structure:

{
  "callingFunction": "..."
}

callingFunction

(required, string) the function that made the query. If available, the function will be used in callsite query statistics.

Per command statistics

The MongoDB filter will gather statistics for commands in the mongo..cmd.. namespace.

Per collection query statistics

The MongoDB filter will gather statistics for queries in the mongo..collection..query. namespace.

Per collection and callsite query statistics

If the application provides the calling function in the $comment field, Envoy will generate per callsite statistics. These statistics match the per collection statistics but are found in the mongo..collection..callsite..query. namespace.

Runtime

The Mongo proxy filter supports the following runtime settings:

mongo.connection_logging_enabled

% of connections that will have logging enabled. Defaults to 100. This allows only a % of connections to have logging, but for all messages on those connections to be logged.

mongo.proxy_enabled

% of connections that will have the proxy enabled at all. Defaults to 100.

mongo.logging_enabled

% of messages that will be logged. Defaults to 100. If less than 100, queries may be logged without replies, etc.

mongo.mongo.drain_close_enabled

% of connections that will be drain closed if the server is draining and would otherwise attempt a drain close. Defaults to 100.

mongo.fault.fixed_delay.percent

Probability of an eligible MongoDB operation to be affected by the injected fault when there is no active fault. Defaults to the percentage specified in the config.

mongo.fault.fixed_delay.duration_ms

The delay duration in milliseconds. Defaults to the duration_ms specified in the config.

Access log format

The access log format is not customizable and has the following layout:

{"time": "...", "message": "...", "upstream_host": "..."}

time

System time that complete message was parsed, including milliseconds.

message

Textual expansion of the message. Whether the message is fully expanded depends on the context. Sometimes summary data is presented to avoid extremely large log sizes.

upstream_host

The upstream host that the connection is proxying to, if available. This is populated if the filter is used along with the TCP proxy filter.

Dynamic Metadata

The Mongo filter emits the following dynamic metadata when enabled via the configuration. This dynamic metadata is available as key-value pairs where the key represents the database and the collection being accessed, and the value is a list of operations performed on the collection.