graph: Add an environment variable for a file-based IPFS cache

Author: lutter

graph/src/env/mappings.rs

@@ -1,4 +1,5 @@
 use std::fmt;
+use std::path::PathBuf;
 
 use super::*;
 
@@ -58,6 +59,9 @@ pub struct EnvVarsMapping {
     /// Set by the environment variable `GRAPH_IPFS_MAX_ATTEMPTS`. Defaults to 100000.
     pub ipfs_max_attempts: usize,
 
+    /// Set by the flag `GRAPH_IPFS_CACHE_LOCATION`.
+    pub ipfs_cache_location: Option<PathBuf>,
+
     /// Set by the flag `GRAPH_ALLOW_NON_DETERMINISTIC_IPFS`. Off by
     /// default.
     pub allow_non_deterministic_ipfs: bool,
@@ -86,6 +90,12 @@ impl TryFrom<InnerMappingHandlers> for EnvVarsMapping {
     type Error = anyhow::Error;
 
     fn try_from(x: InnerMappingHandlers) -> Result<Self, Self::Error> {
+        let ipfs_cache_location = x
+            .ipfs_cache_location
+            .map(PathBuf::from)
+            .map(validate_ipfs_cache_location)
+            .transpose()?;
+
         let vars = Self {
             entity_cache_dead_weight: x.entity_cache_dead_weight.0,
             entity_cache_size: x.entity_cache_size_in_kb * 1000,
@@ -101,6 +111,7 @@ impl TryFrom<InnerMappingHandlers> for EnvVarsMapping {
             max_ipfs_file_bytes: x.max_ipfs_file_bytes.0,
             ipfs_request_limit: x.ipfs_request_limit,
             ipfs_max_attempts: x.ipfs_max_attempts,
+            ipfs_cache_location: ipfs_cache_location,
             allow_non_deterministic_ipfs: x.allow_non_deterministic_ipfs.0,
             disable_declared_calls: x.disable_declared_calls.0,
             store_errors_are_nondeterministic: x.store_errors_are_nondeterministic.0,
@@ -137,10 +148,36 @@ pub struct InnerMappingHandlers {
     ipfs_request_limit: u16,
     #[envconfig(from = "GRAPH_IPFS_MAX_ATTEMPTS", default = "100000")]
     ipfs_max_attempts: usize,
+    #[envconfig(from = "GRAPH_IPFS_CACHE_LOCATION")]
+    ipfs_cache_location: Option<String>,
     #[envconfig(from = "GRAPH_ALLOW_NON_DETERMINISTIC_IPFS", default = "false")]
     allow_non_deterministic_ipfs: EnvVarBoolean,
     #[envconfig(from = "GRAPH_DISABLE_DECLARED_CALLS", default = "false")]
     disable_declared_calls: EnvVarBoolean,
     #[envconfig(from = "GRAPH_STORE_ERRORS_ARE_NON_DETERMINISTIC", default = "false")]
     store_errors_are_nondeterministic: EnvVarBoolean,
 }
+
+fn validate_ipfs_cache_location(path: PathBuf) -> Result<PathBuf, anyhow::Error> {
+    let path = path.canonicalize()?;
+    if !path.is_absolute() {
+        return Err(anyhow::anyhow!(
+            "GRAPH_IPFS_CACHE_LOCATION must be an absolute path: {}",
+            path.display()
+        ));
+    }
+    if !path.is_dir() {
+        return Err(anyhow::anyhow!(
+            "GRAPH_IPFS_CACHE_LOCATION must be a directory: {}",
+            path.display()
+        ));
+    }
+    let metadata = path.metadata()?;
+    if metadata.permissions().readonly() {
+        return Err(anyhow::anyhow!(
+            "GRAPH_IPFS_CACHE_LOCATION must be a writable directory: {}",
+            path.display()
+        ));
+    }
+    Ok(path)
+}