env: Decrease default GRAPH_MAX_IPFS_FILE_BYTES (#4669)

Author: leoyvens

docs/environment-variables.md

@@ -70,7 +70,8 @@ those.
 
 - `GRAPH_IPFS_TIMEOUT`: timeout for IPFS, which includes requests for manifest files
   and from mappings (in seconds, default is 60).
-- `GRAPH_MAX_IPFS_FILE_BYTES`: maximum size for a file that can be retrieved (in bytes, default is 256 MiB).
+- `GRAPH_MAX_IPFS_FILE_BYTES`: maximum size for a file that can be retrieved by an `ipfs cat` call.
+  This affects both subgraph definition files and `file/ipfs` data sources. In bytes, default is 25 MiB.
 - `GRAPH_MAX_IPFS_MAP_FILE_SIZE`: maximum size of files that can be processed
   with `ipfs.map`. When a file is processed through `ipfs.map`, the entities
   generated from that are kept in memory until the entire file is done

graph/src/env/mappings.rs

@@ -46,7 +46,7 @@ pub struct EnvVarsMapping {
     /// Sets the `ipfs.cat` file size limit.
     ///
     /// Set by the environment variable `GRAPH_MAX_IPFS_FILE_BYTES` (expressed in
-    /// bytes). Defaults to 256 MiB.
+    /// bytes). Defaults to 25 MiB.
     pub max_ipfs_file_bytes: usize,
 
     /// Limits per second requests to IPFS for file data sources.
@@ -110,7 +110,7 @@ pub struct InnerMappingHandlers {
     #[envconfig(from = "GRAPH_MAX_IPFS_MAP_FILE_SIZE", default = "")]
     max_ipfs_map_file_size: WithDefaultUsize<usize, { 256 * 1024 * 1024 }>,
     #[envconfig(from = "GRAPH_MAX_IPFS_FILE_BYTES", default = "")]
-    max_ipfs_file_bytes: WithDefaultUsize<usize, { 256 * 1024 * 1024 }>,
+    max_ipfs_file_bytes: WithDefaultUsize<usize, { 25 * 1024 * 1024 }>,
     #[envconfig(from = "GRAPH_IPFS_REQUEST_LIMIT", default = "100")]
     ipfs_request_limit: u16,
     #[envconfig(from = "GRAPH_ALLOW_NON_DETERMINISTIC_IPFS", default = "false")]