Documentation
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Overview ¶
Package config reads oplogtoredis configuration values from environment variables. The documentation for this package also documents all of the configuration options that are available to configure oplogtoredis.
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func BufferSize ¶
func BufferSize() int
BufferSize is the size of the internal buffers that hold oplog messages while they're being processed. It is set via the environment variable `OTR_BUFFER_SIZE` and defaults to 10,000.
func HTTPServerAddr ¶
func HTTPServerAddr() string
HTTPServerAddr the address we bind our HTTP server to. The HTTP server exposes a health-checking endpoint on `/healthz` and Prometheus metrics on `/metrics`. It is set via the environment variable `OTR_HTTP_SERVER_ADDR` and defaults to `0.0.0.0:9000`
func MaxCatchUp ¶
MaxCatchUp is the maximum length of time for which we process old oplog entries. When starting up, if the timestamp of the last entry processes is more than MaxCatchUp ago, we don't try to catch up and just start processing the oplog from the end. If it's less than MaxCatchUp, we process oplog entries starting from the timestamp. This allows us to catch up if oplogtoredis exists and then starts back up. It is set via the environment variable `OTR_MAX_CATCH_UP` and defaults to 60s.
func MongoURL ¶
func MongoURL() string
MongoURL is the Mongo URL configuration. Is is required, and is set via the environment variable `OTR_MONGO_URL`.
func ParseEnv ¶
func ParseEnv() error
ParseEnv parses the current environment variables and updates the stored configuration. It is *not* threadsafe, and should just be called once at the start of the program.
func RedisDedupeExpiration ¶
RedisDedupeExpiration controls the expiration of the Redis keys that are used to ensure we process oplog entries at most once. Every time we publish an oplog entry to Redis, we write its unique timestamp as a Redis expiring key, and check for the existence of that key before doing the actual publish. This allows us to both run multiple copies of oplogtoredis (only one will get to write the key and send the message, the other one will see the key exists and skip publishing), and also ensures that on restart we don't re-publish entries from in between the last time the latest-processed-timestamp was updated in Redis and whne the process existed. It is set via the environment variable `OTR_REDIS_DEDUPE_EXPIRATION` and defaults to 120s.
func RedisMetadataPrefix ¶
func RedisMetadataPrefix() string
RedisMetadataPrefix controls the prefix for keys used to store oplogtoredis metadata (such as the timestamp of the last oplog entry processed). If you're running multiple instances of oplogtoredis for the same MongoDB (for high availability), you should use the same RedisMetadataPrefix for both. If you're running multiple instances for different MongoDBs (because you're using many MongoDB instances with a shared Redis instace, for example), you should have different RedisMetadataPrefixes for each.
This *does not* affect the channel names used to publish oplog entries. The channel names are always `<db-name>.<collection-name>“ and `<db-name>.<collection-name>::<document-id>`.`
It is set via the environment variable `OTR_REDIS_METADATA_PREFIX` and defaults to "oplogtoredis::".
func RedisURL ¶
func RedisURL() string
RedisURL is the Redis URL configuration. It is required, and is set via the environment variable `OTR_REDIS_URL`.
func TimestampFlushInterval ¶
TimestampFlushInterval is how frequently to flush the timestamp of the last processed message to Redis. When we start up, we start tailing the oplog from where we left off (as indicated by this timestamp). It is set via the environment variable `OTR_TIMESTAMP_FLUSH_INTERVAL and defaults to 1s.
Types ¶
This section is empty.
Source Files